MMS Clinical Integration Student Questions Exam 8
A patient comes into the ER complaining of abdominal pain and stool that could be perceived as rice water like. After a conversation with the patient you discover they just came back from vacation and ate prominently seafood throughout their trip. What infection do you suspect this patient is suffering from? A. Shigella B. Salmonella C. Vibrio Cholerae D. Enterotoxigenic Escherichia coli E. Shiga toxin- producing E. coli
C. This patient is suffering from Vibrio cholerae. Although abdominal pain is seen is most enteric infections, the rice watery stool alongside the consumption of seafood are buzz words to demonstrate its association with vibrio
A patient, 25-year-old male, comes into see the physician complaining of abdominal pain, diarrhea, nausea, and fatigue. The physician takes a history and finds out that the patient had been on a fishing trip along a lake with a friend a few days ago. The patient discloses that for the duration of the trip he and his friend ate the fish they caught and cooked them over the fire. The friend that travelled with the patient is not experiencing any symptoms. The doctor has a CBC done and finds that the patient has an MCV of 98 fL (normal = 80-95 fL) and reticulocyte count of 0.3% (normal = 0.5-2%). What organism is most likely responsible and what would be expected to be observed in the stool sample? A. Diphyllobothrium latum, proglottids/eggs in stool B. Ascaris lumbriocoides, eggs in stool C. Giardia intestinalis, cysts in stool D. Enterobius vermicularis, eggs from the Scotch tape test E. Necator duodenale, eggs in fecal smear
A (Answer found on page 795-798) - Three clues are within the stem of the question. First, the patient admits to cooking and consuming fish while on a camping trip with a friend. The patient was not able to confirm if the fish was cooked thoroughly. Second, the friend consumed the same food, but is asymptomatic. D. latum does not always cause symptoms, with most cases being asymptomatic. Third, based on the CBC results included in the question, the patient is suffering from megaloblastic anemia brought on by B12 deficiency due to the tapeworm competing the body for the dietary vitamin.
A 77 year old patient presents to the emergency department with worsening diarrhea and abdominal discomfort for the past few days. The patients describes the diarrhea as watery with little to no blood. A physical examination reveals the patient has a fever of 102 degrees. The patient states that they are currently on antibiotics for a respiratory infection. A stool sample is taken, and a test confirms the presence of a toxin that can cause pseudomembranous colitis. What organism is most likely causing this patients diarrhea and abdominal discomfort? A. Clostridium difficile B. Vibrio cholerae C. Salmonella D. E. coli
A - C.diff is a very common antibiotic associated colitis. The patient states that they are currently on an antibiotic for a respiratory illness. The patient also shows very common symptoms of C.diff. Also, it is the stated that a toxin was detected in the stool sample that can cause pseudomembranous colitis meaning it must be C.diff because none of the other bacteria options cause pseudomembranous colitis.
A 41-year-old male presents to his primary care's office complaining of lumps around his genitalia and inguinal area. The patient is an expat having just returned to the U.S after living in Vietnam for 17 years; says he developed a low grade fever the week he returned, and started noticing painless lumps and nodules two weeks after. The patient has no significant medical history and has been healthy otherwise. Upon taking sexual history the physician learns that the patient has not been sexually active for 6-8 weeks now. During the physical exam the physician notices a small, beefy penile ulcer resembling syphilitic lesions. Which organism and virulence factor is the primary cause of the patient's symptoms? A. granulomatis, capsule. B. ozaenae, toxin coregulated pilus. C. oxytoca, polar flagella. D. gonorrheae, hemolysins. E. pneumoniae, protein capsule. F. ducreyi, fimbriae.
A - Klebsiella granulomatis, an encapsulated gram negative bacillus, is the causative agent of granuloma inguinale - a granulomatous disease affecting the genitalia and inguinal area. Small and beefy ulcers are characteristic symptoms of this disease, more commonly known as donovanosis. Other clues that point to K. granulomatis include the timeline - subcutaneous nodules appear on the genitalia or in the inguinal area after a prolonged incubation of weeks to months (took about 6-8 weeks for the nodule to appear for our patient.) The nodules subsequently break down, revealing one or more painless granulomatous lesions that can extend and coalesce into ulcers resembling syphilitic lesions. Lastly, Donovanosis or granuloma inguinale is rare in the United States but is endemic in parts of Papua New Guinea, the Caribbean, South America, India, southern Africa, Australia, and Vietnam - which has been the residence of our patient for 17 years.
What primarily controls the regulation of attachment, engulfment, and replication on the Salmonella bacterial chromosome? A. Pathogenicity island I and II B. Colonization factor C. LEE pathogenicity island D. Plasminogen activator (pla) protease gene E. pInv genes
A - Pathogenicity island I encodes salmonella-secreted invasion proteins (Ssps) and a type III secretion system that injects the proteins into the host cell. Pathogenicity island II contains genes that allow the bacteria to evade the host's immune response and encodes a second type III secretion system for this function.
A 50-year-old male presents to the emergency department with a fever, abdominal cramping, and mucous diarrhea that is progressively getting worse. He recalls that he attended a birthday picnic yesterday and the weather was very warm. He states that he didn't feel like eating much but did end up eating an egg salad sandwich. Which of the following pathogens is the most likely reason for his diarrhea? A. Salmonella enteritidis B. Salmonella typhi C. Shigella dysenteriae D. Enterotoxigenic Escherichia coli E. Vibrio cholerae
A - Salmonella enteritidis' (nontyphoid salmonella) main mode of transmission is through ingesting contaminated food or water. In this case, it was the egg salad sandwich the patient ate at the outdoor picnic. He also mentions that the temperature was warm, indicating that the sandwiches could not have been refrigerated or kept cool. Symptoms associated with S. enteritidis are fever (usually resolves in 2 days), abdominal cramping, and mucous diarrhea (+/- blood).
A 50 year old patient was treated for H. pylori 7 months ago. When screening the patient's serum what antibodies are most likely still present? A) IgA and IgG B) IgG and IgM C) IgM and IgA D) IgD and IgM E) IgA and IgD
A - Serology is an important screening test for diagnosis of H. pylori. Although IgM disappears rapidly, IgA and IgG antibodies can persist for months to years. Because the antibody titers persist for months to years, this test should not be used to discriminate between past and current infection.
A 20-year-old male comes to the traveler's clinic complaining of profound weakness, dehydration, no fever, and severe diarrhea of about two days duration. He has just returned from Nepal where he worked for one month in a refugee camp. While traveling on the plane he developed abdominal bloating, vomiting, intestinal gurgling followed by two loose bowel movements, and abrupt onset of watery diarrhea occurring hourly. What is the mechanism of transmission of this curved, gram-negative rod bacterium? A. Ingestion of contaminated food and water B. Ingestion of shellfish and seawater C. Ingestion of milk D. Ingestion of uncooked chicken E. Ingestion of uncooked hamburgers
A - The gram-negative curved rod shaped bacteria are Vibrio species. Specifically, the bacterium is Vibrio cholerae due to symptoms of the patient's abrupt onset of diarrhea, vomiting, dehydration, and no fever. This bacterium's primary mechanism of transmission is due to the ingestion of contaminated food and water. The symptoms of this patient and shape should have led you to the correct answer.
A person previously exposed to rats develops a high fever, malaise, and painful bubo around their armpits and groin. They go to their doctor and are diagnosed with bubonic plaque. What gene is responsible for this organism's ability to degrade fibrin clots and spread rapidly? A. pla B. fl C. YopH D. YopE E. YopJ/P
A -Plasminogen activator (pla) protease gene is a virulence factor present in Yersinia pestis which encodes coagulase and fibrinolysin. These enzymes degrade fibrin clots and increase transmissibility of Y. pestis.
Which of the following bacterial infections produces an excess secretion of acid in the stomach? A. Helicobacter pylori B. Campylobacter jejuni C. Clostridium perfringens D. Clostridium difficile E. Vibrio cholerae
A- A bacterial infection that causes excess secretion of acid in the stomach is helicobacter pylori due to its ability to invade the mucosal barrier and release ammonium to stimulate hydrochloric acid secretion.
A patient comes into the emergency department complaining of nausea, vomiting, and fullness after eating. After some testing, the attending physician diagnosed her with chronic gastritis. The physician informs the patient that they may develop pernicious anemia as a side effect because of failure of red blood cell maturation in the absence of vitamin B12. Knowing this information, what cells are being disrupted and what gland of the stomach are they located in? A. Parietal cells located in the oxyntic glands B. Chief cells located in the oxyntic glands C. Parietal cells located in the pyloric glands D. Gastrin cells located in the oxyntic glands E. Gastrin cells located in the pyloric glands
A. (answer found on pages 811-813) - Parietal cells located in the oxyntic glands. Intrinsic factor, which is essential for vitamin B12 absorption in the ileum, is secreted by parietal cells. When the acid-producing parietal cells of the stomach are destroyed, which frequently occurs in patients with chronic gastritis, pernicious anemia may develop as a result of decreased intrinsic factor.
What are the two most important functions of bile? A. Digestion and absorption of fat; excretion of bilirubin out of blood B. Digestion of proteins; excretion of amino acid out of blood C. Absorption of amino acids; excretion of bilirubin out of blood D. Digestion of carbohydrates; Absorption of glucose E. Digestion of proteins; excretion of heme out of blood
A. (answer found on pages 817-819) - Bile salts within bile play two important roles in the digestive tract. First, they aid in the emulsification of large fat particles, lowering the surface tension of the fat particles. This causes the fat globules to break down into smaller pieces. Second, by forming lipid complexes known as micelles, they aid in the absorption of fatty acids, monoglycerides, cholesterol, and other lipids from the intestinal tract. Bile is also involved in the excretion of waste products from the blood, including bilirubin and excess cholesterol.
A 30 year old female presents to the clinic with diarrhea, bloating, fatigue, and weight loss. She has been experiencing these symptoms ever since she has increased her gluten intake. Her physician thinks she may be presenting symptoms of celiac disease, which is an autoimmune disease that damages the lining of the small intestine. What is in the lining of the small intestine and what is its significance? A. Villi; increases the surface area of the absorptive mucosa B. Amylase; digestion of the starches C. Bile salts; digestion of fats D. Secretin; increases bile secretion E. CCK; increases digestive enzymes by acinar cells
A. (page 827) - Villi are found in the lining of the small intestine and their function is to increase the surface area of intestine to allow for absorption of nutrients. People with celiac disease eat gluten and this damages the villi leading to malabsorption.
A 30-year-old female patient with a medical history of occult colon cancer and diabetes presents to the emergency room with a severe case of myonecrosis that began 2 days ago with no known recent trauma. Patient is admitted into the hospital and expires later that night. Which of the following bacterial species are most likely the result of her symptoms. A. Clostridium septicum B. Clostridium botulinum C. Clostridium tetani D. Clostridium difficile E. Clostridium tertium
A. Clostridium septicum is the correct answer as is seen by three main clues. First clue is that the myonecrotic infection is atraumatic, a unique characteristic for C. septicum. The second clue is that the patient has a hx of occult colon cancer and diabetes, both of which are commonly seen with patient's who develop myonecrotic infections from C. septicum. The last clue is the quick expiration (death) of the patient after onset of symptoms, with most patient's expiring 1 to 2 days after initial presentation which is referred to as a "fulminant course"
Tom, a 22-year-old male presents to the clinic with explosive watery diarrhea and abdominal cramps for 2 days. He states that he came back from a trip to Mexico 4 days ago and remembers eating questionable food from a buffet. He was diagnosed with Traveler's Diarrhea. What's the most common cause of Traveler's Diarrhea? A. ETEC B. EPEC C. EHEC D. C. difficile E. STEC
A. ETEC is the most common cause for Traveler's Diarrhea. It causes abrupt explosive watery diarrhea, abdominal cramps, fever, and nausea/vomiting. The incubation period is 24-72 hours.
A 26-year-old male presents to the emergency department with complaints of abdominal cramps and watery diarrhea but no fever, nausea, or vomiting. Last night he ingested leftover turkey with gravy, with clinical symptoms manifesting within 8 hours. The physician suspects food poisoning and laboratory results indicate gram positive, rod shaped and spore forming bacterium. Which of the following would be the most appropriate clinical intervention? A. Oral rehydration B. Antibiotic therapy C. Vaccination D. Metronidazole E. Surgical debridement
A. Given the morphology and clinical symptoms, this is a case of clostridial food poisoning. This is managed by oral rehydration and in severe cases intravenous fluids and electrolytes.
Feeling hungry and not wanting to make a trip to Walgreens in the snow, Michael decided to reheat 5 day salmon he had sitting in the fridge. In the time it was sitting in the fridge, a colony of Enterotoxigenic E. Coli (ETEC) began growing, and the microwave destroyed the heat-labile toxin produced by this bacteria. By what mechanism does the heat-stable toxin from ETEC cause diarrhea? A. Increase in cGMP B. Increase in cAMP C. Invasion of intestinal cells D. Neutralization of gastric acid E. Inactivation of eukaryotic ribosome
A. Increase in cGMP is the correct answer because the heat-stable toxins of E. Coli (ETEC) acts by activating guanylate cyclase to produce cyclic guanosine monophosphate (cGMP) intracellularly which causes an increase in Cl- secretion and an increase in fluid secretion, leading to diarrhea.
While on a cruise a 26 year old patient presents to the physician, presenting with diarrhea, vomiting, headache, mild fever and stomach cramps. The patient shares that she was playing with her toddler nephews when she noticed one of them pooped in the pool, so she grabbed it and disposed of it quickly. Approximately 15 hours later she began experiencing symptoms. After diagnosis from the physician, the patient is healthy within 3 days. What virus does the physician suspect the patient is suffering from? A. Norovirus B. Salmonella C. Giardia Lamblia D. Rotavirus E. Poxvirus
A. Norovirus is known to present on cruise ships within 12-72 hours. It is transmitted when fecal matter/vomit from an infected person enters another's mouth, when touching contaminated surfaces, shaking hands, or providing care, thus highly contagious. Key symptoms are diarrhea, vomiting, and fever. The patient was in contact with feces and all of the particles may not have been removed from her hands, so when she next touched her face she would have infected herself.
A 4-month-old infant ingested some honey while her unemployed mother neglected her to shoot a TikTok video. The infant began suffering some strange symptoms the next few days and was rushed to the emergency room. Which symptom does the infant most likely present with? A. Flaccid Paralysis B. Necrotizing Fasciitis C. Anemia D. Gout E. Depression
A. because the infant ingested honey and Clostridium botulinum colonized the GI tract causing flaccid paralysis. Infant botulism is the most common form of botulism in the USA.
Which of the following pathogenic Escherichia coli produce Shiga-like toxins and cause clinical symptoms similar to those resulting from S. dysenteriae infection. A. Enteropathogenic E. coli B. Enterohemorrhagic E. coli C. Enterotoxigenic E. coli D. Enteroaggregative E. coli E. Enteroinvasive E. coli
B (Answer found on page 792) - Both O157:H7 and non-O157:H7 serotypes produce the Shiga-like toxin
A group of students goes to a seafood restaurant to celebrate after a big midterm exam. The group enjoys a variety of shellfish and other local delicacies. The next morning, they head home but on the way several of them begin to feel a really urgent need for a rest area. Within the next hour, everyone is enjoying an explosive watery diarrhea, vomiting, nausea, abdominal cramps, and headaches. Once they got back home, they were still feeling intense symptoms, so they decided to go for a checkup. Vitals were normal and no one had fever. Which of the following diseases does this resemble? A. Vibrio cholera B. Vibrio parahaemolyticus disease C. Aeromans wound infection D. Vibrio vulnificus E. Aeromonas veronii
B - After eating a few oysters, many ill individuals had explosive watery diarrhea, reported abdominal cramping, chills, myalgias, headache, and vomiting, with symptoms lasting a median of 5 days. This outbreak illustrates the role of contaminated shellfish in V. parahaemolyticus disease and the clinical symptoms typically observed.
A 68 year old male presents to the emergency department with persistent nausea, vomiting, and the feeling of fullness. He describes that he has had similar episodes of symptoms in years past, but that they are becoming worse and more frequent. Lab diagnostics reveal that his infection is caused by an urease producing bacteria that is transmitted via the fecal-oral route. Which disease complication is the physician most worried about in this patient? A. Scarlet fever B. Gastric adenocarcinoma C. Guillain-Barre syndrome D. Reactive arthritis E. Pseudomembranous colitis
B - Gastric adenocarcinoma is a possible complication of Helobacter pylori infections. The fecal-oral transmission, urease positive, and symptoms are all highly indicative of a Helobacter species. B is the only complication out of the options that describes a complication of a helicobacter infection.
A researcher creates a targeted loss-of-function mutation in the Vibrio cholerae zot (zonula occludens toxin) gene. Due to this mutation, what will the bacteria no longer be able to do? A. Adhere to the intestinal mucosal cells B. Increase intestinal permeability C. Induce hypersecretion of electrolytes and water D. Bind to bacteriophage E. Avoid phagocytosis
B - The loss-of-function mutation in the zot gene prevents the bacteria from disrupting the tight junctions (zonula occludens) in the intestinal epithelium. Since the bacteria are no longer able to disrupt the tight junctions, intestinal permeability cannot be increased.
A 27-year-old woman presents to the urgent care with abdominal pain and bloating over the last month. She also complains of intermittent, copious, non-bloody diarrhea over the same time. Last month, she first noticed a small rash on her leg, and then developed a cough that has since improved but has not completely resolved. She has no sick contacts and has not left the country recently. Physical examination is notable for a small pink streak on her right leg. Serum laboratory studies are pending. Examination of her stool reveals the causative organism. This organism is most likely transmitted to the human host through which of the following routes? A. Inhalation B. Penetration of skin C. Animal bite D. Insect bite E. Sexual contact
B - This patient presenting with both pulmonary and abdominal symptoms after a rash is most likely infected with roundworms, Strongyloides; which is transmitted through penetration of the skin. They migrate through the lungs, where they induce inflammatory infiltrates, and then reside in the intestine while maturing into adult worms.
Chaise comes into the clinic complaining of an abrupt onset of watery diarrhea that resembles rice water, vomiting, and abdominal pain. He recently went to Haiti after their earthquake, to help those affected by the disaster. A gram stain is done, and it is found that the causative agent is a gram negative, comma shaped bacteria. Which of the following is the primary way to transmit this disease? A. Sexual Intercourse B. Drinking contaminated water C. Sharing a towel D. Puncture wound
B is the correct answer because Chaise has been infected with Vibrio Cholera. Watery diarrhea that resembles rice water is a buzz word for Cholera. Cholera has a negative gram stain and has a comma shape. It is transmitted fecal- oral and is commonly seen in areas that have recently suffered a natural disaster.
A 70 year old man presents to the emergency room with severe upper abdominal pain that radiates to his back, nausea, and vomiting. His medical history includes hyperlipidemia and hypertriglyceridemia. He drinks 13 beers daily. Which of the following is the most likely cause of his symptoms? A. Sprue B. Pancreatitis C. Gastritis D. Enteritis E. Ulcerative colitis
B- A common cause of pancreatitis is drinking excess alcohol. Drinking excess alcohol can cause enzymes to digest the pancreas. This digestion can destroy the ability of the pancreas to secrete digestive enzymes, which interferes with fat digestion.
A 26 year old patient presents to the emergency room with extreme gastrointestinal discomfort. After several exams, it is determined that the patient is suffering from gastric atrophy and the pH of their stomach after maximum stimulation remains above 6.5 due to a complete lack of HCl secretion in the stomach. What condition would be included in the patient's diagnosis? A. Lactose Intolerance B. Achlorhydria C. Sickle Cell Anemia D. Peptic Ulcer caused by H. pylori infection E. Megaesophagus
B- Achlorhydria is a condition caused by the failure of the stomach to release HCl. A patient is diagnosed with this condition when the pH of their stomach does not fall below 6.5 after maximum stimulation.
A 52 year-old male present to the emergency room vomiting blood, dark tarry stools, and burning stomach pains. Through culturing, it is determined that the patient has peptic ulcers caused by H. pylori. Of the potential virulence factors listed below, which is the most crucial for initial colonization in the host? A. Capsule B. Neutralization of gastric acids with the ammonia produced by bacterial urease activity. C. Secretion of vacuolating cytotoxin A (VacA) D. Surface adhesion proteins E. Cytotoxin-associated gene (cagA)
B- If the bacteria cannot neutralize the acid in the host's stomach, it will not be able to survive. Therefore, in order to colonize the host, it must be able to survive the stomach, which it does by neutralizing gastric acid through ammonia.
A patient presents with bloody diarrhea, lesions, hemolytic uremic syndrome, and ischemic colitis. The patient is a cow farmer. Their diet includes frequent beef consumption with meat being prepared in many ways. They state that those who he supplied the beef to, are also experiencing similar symptoms. Which toxin is causing the lesions that may also resemble the lesions produced by a different bacterial infection? A. Heat-stable toxin B. Shiga-like toxin C. Shigella D. EHEC E. Cholera toxin
B- Shiga-like toxin. This question is describing a patent with Enterohemorrhagic E. Coli, or EHEC. EHEC is often caused by consumption of contaminated beef. The Shiga-like toxins are responsible for the lesions and similar presentation of symptoms to S. dysenteriae. These stereotypes, O157:H7 and non O157:H7, bloody diarrhea, hemolytic-uremic syndrome, and ischemic colitis.
A 24 year old female has an excessively extended duodenum that triggers her to vomit. What action will not occur during the preparation of the vomiting act? A. Raising of the hyoid bone B. Descending of the soft palate to open posterior nares C. A deep breath D. Downward contraction of the diaphragm E. Closure of the glottis
B- The soft palate is lifted to close the posterior nares; not descended to open them
A 52-year-old female presents to the ER with upper abdominal pain as well as an abrupt onset fever. The physician diagnoses the patient with acute pancreatitis based on these symptoms. What is most likely the primary factor for this patient's condition? A. Inhibition of enterokinase B. Trypsin inhibitor is overwhelmed C. Decreased activation of pancreatic enzymes D. Trypsin inhibitor is working normally E. Increased pancreatic secretion
B. (answer found on page 815) - Trypsin inhibitor is released from the pancreas at the same time as other digestive enzymes being secreted. The purpose of this inhibitor is to prevent premature activation of trypsin in the pancreas. In this patient's condition, the pancreas is likely damaged and causes blockage of secretion. This prevents the appropriate regulation of digestive enzymes due to trypsin inhibitors being overwhelmed and allows for enzymes to digest the pancreas, giving rise to acute pancreatitis.
A 64-year-old male comes to the emergency room presenting with peptic ulcers. He has a history of being very excitable, and his sympathetic nervous system is likely being stimulated often. What function in the duodenum of this patient is being inhibited which would protect against these ulcers? A. Water and electrolyte secretion of Brunner's glands B. Mucus secretion of Brunner's glands C. Mucus secretion of crypts of Lieberkühn D. Mucus secretion of goblet cells E. Mucus secretion of enterocytes
B. (answer found on page 820) - Brunner's glands are located in the wall of the first few centimeters of the duodenum. They secrete large amounts of alkaline mucus to protect the duodenal wall from digestion by the highly acidic gastric juice emptying from the stomach. Brunner's glands are inhibited by sympathetic stimulation, which can leave the duodenal bulb unprotected and cause this area of the gastrointestinal tract to be a common site for peptic ulcers.
A 31 year old male presents to his urologist with infertility. His urologist determines that the patient is lacking expression of the transporter responsible for supplying his spermatozoa with fructose. He explains to the patient that this transporter is also found on the apical membrane of his intestinal epithelial cells where it is responsible for facilitating the absorption of fructose. Which of the following transporters does this describe? A. SGLT1 B. GLUT5 C. SGLT2 D. GLUT1 E. GLUT2
B. (page 830) - GLUT5 is the transporter responsible for facilitating the diffusion of fructose. GLUT5 is found on the apical membrane of epithelial cells in the intestines. It is also found in the testis (because fructose is an essential nutrient required for spermatozoa), kidneys, brain, skeletal muscle and white adipose tissue.
After a strenuous kickboxing workout, a medical student goes back to her apartment to make scrambled eggs for breakfast. Most of this protein will be digested in the upper small intestine by pancreatic proteolytic enzymes, which include all of the following EXCEPT: A. Trypsin B. Pepsin C. Carboxypolypeptidase D. Elastase E. Chymotrypsin
B. (pages 824-825) - Pepsin is a proteolytic enzyme secreted by the stomach (NOT the pancreas). While pepsin initiates protein digestion, it usually provides only 10-20% of total protein digestion. Pepsin is most active at acidic pH (2.0-3.0).
Sodium plays an important role in helping to absorb carbohydrates and amino acids within the small intestine. Which ion utilizes the positive electrical gradient created by sodium to passively exit the intestinal epithelium through the basolateral membrane for absorption? A. Hydrogen B. Chloride C. Bicarbonate D. Potassium E. Iron
B. (pages 828-829) - Chloride ion absorption mainly occurs via diffusion within the intestinal epithelium. The negatively charged Chloride ions are able to travel passively through Chloride channels on the basolateral membrane of the epithelial cell during absorption because it is being dragged by the positive electrical charges of sodium.
In celebration of a successful rocket launch, Elon ate his favorite fried rice dish (with lots of vegetables and bean sprouts) that has been left out, unrefrigerated, overnight. 5 hours after eating, he experienced vomiting and diarrhea, but did not have a fever. If it was determined that these symptoms were caused by ingestion of a preformed toxin, which bacterial strain is most likely the culprit? A. Giardia lamblia B. Campylobacter jejuni C. Bacillus cereus D. Vibrio cholerae E. Cryptosporidium parvum
B. B. cereus is the only bacteria in these answer choices that has an incubation time of 1 to 6 hours, that is a toxin producing bacteria in contaminated fried rice, vegetables, or sprouts.
A 38-year-old male with a medical history of type II diabetes presents to the emergency department with high grade fever and abdominal pain. He states that he fell while gardening four days ago. Physical examination reveals the presence of a painful blister on his right foot. A sample was taken from the blister, stained and cultured on blood agar. Gram-positive rods were observed as well as anaerobic sporulated Gram-positive bacillus. Which of the following is the most likely cause of infection? A. Necrotizing Fasciitis B. Clostridium tertium C. Localized tetanus D. Clostridium sordellii E. Clostridium perfringens
B. Clostridium tertium: An opportunistic infection associated with traumatic wound infections in which correct identification can be made once spores are observed and determined to grow better anaerobically.
A 26-year-old male is taken to the emergency department because he has been experiencing profuse sweating, drooling and facial spasms. Upon examination, the patient informs the physician that he was recently in a bicycle accident that left him with a wound on his arm, which he never sought treatment for. There was no evidence of other wounds on the patient. Which of the following is the patient most likely suffering from? A. Localized tetanus B. Generalized tetanus C. Cephalic tetanus D. Neonatal tetanus E. Wound botulism
B. Generalized tetanus has the involvement of the masseter muscles no matter where the primary site of infection occurs. This patient is suffering from Lockjaw based on his symptoms, which is the most presenting sign of generalized tetanus.
A 45-year-old male presents to the ER with severe rapid onset of pain in his left leg. Physical examination reveals a laceration to the lower leg that is dark red and purple in color. The patient states the laceration occurred 3 days prior while he was digging up ground for a new pool he is installing. Lab tests show this is a gram positive, spore forming rod. If this patient did not come in for any medical intervention, what other symptoms could present in the following days? A. Nothing, the wound would have self-resolved in the following week. B. This could lead to muscle necrosis, renal failure, shock, and death without medical intervention C. This could lead to a pseudomembranous colitis with profuse diarrhea, abdominal pain, and fever. D. This could lead to bilateral flaccid paralysis that is ascending from the laceration. E. This could lead to spastic paralysis, lock jaw, and trouble breathing.
B. The question stem indicates that the patient is in the early stages of gas gangrene caused by Clostridium perfringens. The lab tests show the bacterium is a gram-positive rod that is spore forming, which can narrow it down to Clostridium or Bacillus. The patient's symptoms are severe rapid onset of pain, and dark red/purple color surrounding the laceration. The patient's history indicates the laceration occurred while outside moving soil to provide a wound entry for the C. perfringens.
A 27-year-old male, day care worker presents to his PCP with chief complaint of diarrhea, fever, and abdominal pain that started about 4 days ago, but decided to come in once he saw blood in the diarrhea. After taking stool sample cultures, the PCP diagnoses him with a gram negative, hydrogen sulfide negative, facultative anaerobe. What treatment plan is most likely prescribed for this patient to shorten the clinical course? A. Ibuprofen B. IV fluid only C. Antibiotic treatment D. Antidiarrheal medication E. Pepto Bismol
C (Answer found on page 790) - The gram negative, hydrogen sulfide negative, facultative anaerobe is Shigella. Antibiotic treatment will shorten the clinical course and the duration of bacterial shedding in stools
A patient presents to the emergency department with complaints of abdominal pain, nausea, vomiting and abdominal tenderness on palpation. The patient is found to have Yersinia enterocolitica. Which of the following is least associated with the infection caused by this organism? A. Pork B. Raw milk C. Summer months/weather D. Winter months/weather E. Contaminated water
C (Answer found on page 792) - Yersinia infections are most commonly associated with pork, raw milk, contaminated water, and are seen more during the winter.
A 24-year-old female patient complains of intermittent diarrhea that started approximately one month ago; she states that the diarrhea has been happening ever since she went on a Caribbean cruise and has persisted since. The patient has also undergone a kidney transplant a few years ago due to an autoimmune condition and has been on an immunosuppressant ever since. Which of the following is true with regards to the most likely causative agent? A. It contains a thick peptidoglycan wall B. It has a very high infective dose at around 105 particles C. It has a single-stranded RNA genome D. It contains NSP4 proteins that destroy mature enterocytes E. It is readily destroyed at freezing temperature
C (Answer found on page 794) - The patient most likely contracted norovirus (single-stranded (+) sense RNA genome) from her cruise; and since she is on an immunosuppressant, the virus failed to clear and now she is suffering from chronic diarrhea
A 25-year-old female presents to her physician with complaints of on-going diarrhea. She tells the physician that the diarrhea has lasted for 3 days, upon her return home from her honeymoon, where she ate a lot of shellfish. A stool sample was collected and processed for examination. Assessment of the stool sample showed the presence of a gram-negative curved rod, that is a fermentative, facultative anaerobe, that requires salt to grow. Also present was the Kanagawa hemolysin. Which of the following is most likely responsible for the patient's diarrhea? A. Vibrio cholerae B. Vibrio vulnificus C. Vibrio parahaemolyticus D. Aeromonas caviae E. Aeromonas hydrophila
C - Bacteria of the Vibrio family are fermentative, facultative anaerobes, and require salt to grow. Since they require salt to grow, they are often associated with shellfish that live in saltwater. These factors are mentioned in the question, which allows the correct answer to be narrowed down to a bacteria of the Vibrio spp. Also in the question, it is stated that the Kanagawa hemolysin is present, which is a specific virulence factor for pathogenic strains of Vibrio parahaemolyticus, making C the correct answer choice.
A 27-year-old male infected with HIV presents to the Emergency Department with diarrhea. He is diagnosed with a type of E. coli. This type of E. coli contains adherence of brick-like rods to the epithelium surface and a mucus biofilm that inhibits the absorption of fluids. What type of E. coli was the patient diagnosed with? A. Enterotoxigenic (ETEC) B. Enteroinvasive (EIEC) C. Enteroaggregative (EAEC) D. Enterohemorrhagic (EHEC) E. Enteropathogenic (EPEC)
C - EAEC produces an adherence of rods in brick-like aggregates (autoagglutinations) and the mucus biofilm causes diarrhea by inhibiting fluid absorption.
A 24 y.o. Patient presents to the ED with symptoms of septic shock. Samples were taken, and pathology confirms that the etiology of the suspected septic shock is due to LPS. Lipopolysaccharides (LPS) are composed of, and found in? A. N-acetyl-glucosamine, N-acetyl-muramic acid: Gram negative bacteria B. Lipid A, Core polysaccharide, O polysaccharide: Gram positive bacteria C. Lipid A, Core polysaccharide, O polysaccharide: Gram negative bacteria D. N-acetyl-glucosamine, N-acetyl-muramic acid: Gram positive bacteria E. N-acetyl-glucosamine, N-acetyl-muramic acid: Acid fast staining bacteria
C - LPS is composed of Lipid A, Core polysaccharide, O polysaccharide, and found in gram negative bacteria. This endotoxin, when released by cell lysis, can cause septic shock with sufficient quantity.
A 27 year old female presents to the ER after cutting herself and being unable to stop the bleeding. Upon questioning, she also reports complaints of fatigue, weight loss, generalized weakness, lethargy, and pale and foul-smelling stools for the past two weeks, and that she had returned from visiting family in the Caribbean three weeks ago. What is the most likely cause of her symptoms? A. Consuming wheat and rye flour B. Excess secretion of acid and pepsin by the gastric mucosa C. Infectious agents D. Damage to cerebral nerves E. Sigmoid colon spasms
C- Given the patient's symptoms, especially those of being unable to control her bleeding and pale, foul-smelling stools, it is likely that she may be suffering from sprue. Her bleeding problems can be attributed to malabsorption of Vitamin K, and the quality of her stools can be explained by impaired fat absorption (the description of her stool matches that of fatty stools). Her other symptoms could be explained by protein, carbohydrate, folate, and Vitamin B12 malabsorption. These symptoms are all indicative of sprue. Given her travel history to the Caribbean, it is more likely that she has Tropical Sprue rather than Nontropical Sprue (celiac disease). It is believed that unidentified infectious agents cause inflammation in the intestinal mucosa for patients with tropical sprue.
A 28 year-old patient presents to her physician complaining of being unable to pass stool for the past several days and feels constipated. Her physician reveals that her patient has a deficiency of ganglion cells in the myenteric plexus in a segment of the sigmoid colon. Which of the following disorders of the large intestine is most likely evident? A. Ulcerative Colitis B. Enteritis C. Megacolon (Hirschsprung's Disease) D. Psychogenic Diarrhea E. Pancreatitis
C- Megacolon (Hirschsprung's Disease) - Megacolon, also known as Hirschsprung's Disease, is caused by a deficiency of ganglion cells in the myenteric plexus in a segment of the sigmoid colon. As a result, neither defecation reflexes nor strong peristaltic motility can occur in this area of the large intestine, which causes the constipation.
A 7-year-old child is brought to the pediatric office by his mother with a chief complaint of hypersalivation. A drug that affects salivary flow is administered. The goal of the drug is to decrease salivary flow. Which of the following changes in salivary ion secretions would this drug most likely trigger? A. B. C. D. E.
C. (answer found on pages 809-810) - Salivary secretions occur in the salivary ducts, where in normal conditions Na+ is actively reabsorbed and K+ is actively secreted in exchange for Na+. This creates a negative electrical gradient, and Cl- is passively reabsorbed while HCO3- is secreted by the ductal epithelium and into the lumen. Since the administered drug decreases salivary flow rate, saliva spends more time in the salivary ducts and undergoes increased ductal modifications. More Na+ and Cl- would undergo reabsorption therefore decreased levels will be present in the saliva. Conversely, more K+ and HCO3- would undergo secretion therefore increased levels will be present in the saliva.
Which of the following is consumed by humans but not hydrolyzed by the enzymes of the human digestive tract? A. Sucrose B. Starch C. Cellulose D. Lactose E. Maltose
C. (pages 823-824) - Cellulose, the human diet can contain a large amount of cellulose, which is a carbohydrate but the enzymes capable of hydrolyzing cellulose are not secreted in the human digestive tract.
A 72-year-old heart transplant patient has been in the hospital for several weeks and is currently taking clindamycin along with several immunosuppressants. During rounds, his nurse reports that the patient now has a fever, elevated WBC count, and frequent watery bowel movements. The doctor discontinues the clindamycin and orders a stool sample be sent to the lab for enzyme immunoassay, nucleic acid amplification test, and glutamate dehydrogenase test. What is the likely causative bacterial agent? A. Vibrio cholerae B. Rotavirus C. Clostridium difficile D. Norovirus E. Giardia lamblia
C. C. difficile is the correct answer because it causes fever, elevated white blood cell count, and frequent watery bowel movements especially in patients who are hospitalized, immunosuppressed (recent heart transplant), older than 65, and on antibiotics. Additionally, the doctor discontinued the antibiotic and ordered lab tests (enzyme immunoassay, nucleic acid amplification test, glutamate dehydrogenase tests) that can specifically test for C. diff. toxin.
A 65-year-old patient presents to his primary care physician with a chief complaint of severe diarrhea and abdominal cramping that started 2 days ago and is not resolving. Patient's PCP learns that the patient was prescribed Clindamycin 7 days ago after visiting the ER for a bacterial infection. Colonoscopy reveals the patient has pseudomembranous colitis. Which of the following toxins is responsible for the patient's severe diarrhea? A. Beta Toxin B. Epsilon Toxin C. Enterotoxin (Toxin A) D. Cholera Toxin E. Tetanospasmin
C. Clues in the question stem point to Clostridium difficile, which produces enterotoxin (toxin A) and cytotoxin (toxin B). One major symptom is antibiotic associated diarrhea that starts 5 to 10 days after starting a broad-spectrum antibiotic (in this case Clindamycin). Pseudomembranous colitis is also a characteristic sign of C. difficile. Enterotoxin (Toxin A) disrupts the tight junctions in cells, increasing permeability of the intestinal wall, which causes diarrhea and inflammation
A 4 year-old patient presents to the emergency department with bloody diarrhea and rectal bleeding. Upon further examination, his temperature was 102.4° F , and the patient also complained of abdominal cramping and flank pain. The mother of the patient is worried that her son is not urinating enough, and states that there blood is present in his urine. The physician collects a stool sample as he is concerned that this may be a bacterial infection due to the patient's recent history of possible exposure to contaminated food or water. The sample was found to be positive for S. dysenteriae type 1 shigellosis. What major complication is this child presenting with? A. Kidney Stones B. Toxic Shock Syndrome C. Hemolytic-Uremic Syndrome D. Listeriosis E. Reactive Arthritis
C. Complications of S. dysenteriae type 1 shigellosis include Hemolytic-uremic syndrome (HUS). The presentation of flank pain, oliguria, and hematuria are all indications that there is a kidney problem with this patient and potentially resulting in kidney failure. Hemolytic-uremic syndrome presents in patients mainly < 5 years of age.
While doing rounds on nightshift, a GI resident reads a new patient's medical history that states he has not had a regular bowel movement in the past 3 days and is experiencing severe abdominal distention and pain. The medical history states that he was recently treated for a Vibrio infection 4 days ago and given Azithromycin while at a different hospital. After an abdominal exam and sigmoidoscopy, the resident suspects toxic megacolon. What would most likely be the cause of the patient's megacolon? A. Microvillus inclusion disease B. Whipple disease C. Trichuris trichiura infection D. Pseudomembranous colitis E. Cryptosporidium infection F. Intestinal obstruction
D (Answer found on page 793) - the delayed bowel movement causing a backup of fecal matter in the colon is indicative of pseudomembranous colitis. The patient has also recently had a Vibrio infection and was treated with Azithromycin which can kill other normal flora bacteria thus allowing C. difficile to populate the colon. This will cause erosion of microvilli leading to "volcano" eruptions of leukocytes into the fecal matter. On sigmoidoscopy, the resident would be able to see yellow/white lesions on the colon lumen.
A 32-year-old immigrant from southeastern Asia complains of intermittent abdominal cramps. He has had multiple respiratory infections over the last two years as well as a persistent, chronic cough. Laboratory results are as follows: Complete Blood Count Hemoglobin 13.0 g/dL Leukocytes 6,800 cells/uL Neutrophils 56% Eosinophils 14% Lymphocytes 26% Monocytes 4% Which of the following findings in this patient would be most suggestive of a Strongyloides infection? A. Parasite eggs in the stool B. Perianal egg deposition C. Proglottids in the stool D. Noninfectious larvae in the stool E. Trophozoites and cysts in the stool
D (Answer found on page 796) - Strongyloides is a roundworm disease that is transmitted by infectious larvae found in soil contaminated with human feces. On contact, the larvae penetrate the skin and migrate hematogenously to the lungs. There they enter the alveoli and travel up the bronchial tree to the pharynx, where they are swallowed. When the larvae reach the intestine, they develop into adults that lay eggs within the intestinal mucosa. These hatch into noninfectious larvae that migrate into the intestinal lumen to be excreted in the stool.
A 68- year old woman presents to the emergency department with complaints of bloody diarrhea with severe pain in the abdomen and stomach area. Her medical history was not unusual and she has not undergone regular health checkups. She reports that she enjoys seafood and typically has sushi at least once a week. When asked about recent travel, she reports going canoeing on Lake Erie a few days prior. Microscopic findings show gram negative straight bacilli. Further tests were conducted and it was discovered that the bacteria does not grow on TCBS (thiosulfate- citrate-bile salts-sucrose) agar. What genus does this bacteria belong to? A. Vibrio B. Clostridium C. Listeria D. Aeromonas E. Lactobacillus
D - Aeromonas is a genus of gram negative, straight bacilli bacteria. It is ubiquitous in fresh and brackish water. This genus of bacteria does not grow TCBS agar. Aeromonas infection can present as dysenteric diarrhea characterized by severe abdominal pain and blood with leukocytes in the stools. The morphology, symptoms, and inability to grow on TCBS makes Aeromonas the correct answer.
A 36-year-old male has been seen by his GI physician for a routine appointment. He often has bloody diarrhea, fever, and stomach cramps. He is diagnosed with gastroenteritis as a result of contracting Campylobacter jejuni infection by consuming undercooked seafood at a summer family reunion party. He is treated with fluid and electrolyte replacement therapy, but his body doesn't seem to respond well. The Gastroenterologist must advise the patient to immediately start taking which of the following for his rising gastroenteritis severity? A. Omeprazole B. Ciprofloxacin C. Levofloxacin D. Azithromycin E. Metronidazole
D - Campylobacter jejuni gastroenteritis is typically a self-limited infection managed by the replacement of lost fluids and electrolytes. Antibiotic therapy may be used in patients with severe infection or septicemia. However, not all antibiotics are effective enough to fight against the infection as C. jejuni is known to display resistance to a few antibiotics. Currently, Azithromycin or Erythromycin are the first antibiotics of choice for the treatment of severe gastroenteritis.
Which of the following statements is not true regarding laboratory diagnosis of enterobacteria infection? A. Nucleic Acid Amplification Tests allow for simultaneous identification of multiple species. B. Most species of enterobacteria can be identified by characteristic mass spectrometry of their protein profiles. C. Use of differential agars help differentiate between lactose fermenting and lactose non-fermenting enterobacteria. D. Warm Enrichment' is a common culturing technique for certain species such as Y. enterocolitica. E. Serologic testing is useful in identifying certain species such as E. coli 0157.
D - Cold enrichment, not warm enrichment is a common culturing technique for species such as Y. enterocolitica, as this species prefers cooler temperatures for growth. This also helps during culturing in killing other organisms who cannot grow in lower temperatures and maintaining sample purity.
A 24-year-old male patient with β-thalassemia calls into the clinic where he regularly goes for transfusions stating he has come down with a stomach bug and does not feel well enough to come in for his next appointment. When he fails to show up for the scheduled follow-up, the clinic learns he has been hospitalized with sepsis and is on the verge of death. Which of the following pathogens is the most likely cause of his "stomach bug"? A. Vibrio cholera B. Salmonella enterica typhi C. Enterohemorrhagic Escherichia choli (EHEC) D. Yersinia enterocolitica E. Shigella dysenteriae
D - In Yersinia infection, non-heme iron enhances virulence and increases systemic dissemination. In patients with chronic anemia or hemochromatosis, the presence of non-heme iron increases the risk of sepsis and death due to infection. In this patient, the frequent transfusions likely results in secondary hemochromatosis, allowing for the progression of infection to an extreme.
A 4 y/o female is brought to the emergency room by her mother, complains of watery diarrhea that started 2 days after they took a trip to the apple orchard, where they consumed cider donuts and apple cider juice. The mother notes that the symptoms started off as a watery diarrhea and then progressed into grossly bloody diarrhea 2 days later. She also notes that the child experienced emesis but denies any fever. Which virulence factor associated with E. coli is responsible for causing the above symptoms? A. Sta toxin B. HlyA C. Entero-aggregative heat-stable toxin D. Stx2 E. LT-I
D - Most infections associated with STEC (which produce Stx1 and Stx2 toxins) are attributed to the consumption of cider made from apples contaminated with feces from cattle, among other foods. This strain can lead to watery diarrhea that progresses into grossly bloody diarrhea and vomiting without presence of fever.
Which of the following viruses is known to selectively infect and destroy mature enterocytes in the small intestine with a very specific compensatory immature epithelial cells of the villus surface? A. Retrovirus B. Norovirus C. Adenovirus D. Rotavirus E. Rhinovirus
D - Rotavirus selectively infects and destroys small intestine enterocytes which leads to the repopulation of the villus surface by immature epithelial cells.
A 26 year old male was seen in a hospital in Haiti 3 days after an earthquake. The natural disaster severely damaged the water supply and sanitation of waste removal systems. The patient complains of malaise, fatigue, and severe watery diarrhea. Which of the following virulence factors least likely contributes to the actions of the most likely causative pathogen? A. Zonula occludens toxin B. Accessory cholera enterotoxin C. TCP D. TDH E. Chemotaxis proteins
D - TDH or thermostable direct hemolysin is an adhesin produced by V. parahaemolyticus. This bacteria does not cause the illness cholera, the disease being referenced in the question.
The microbe responsible for being the most common cause of bacterial diarrhea in the United States can be transmitted via all of the following except? A) Milk B) Fecal-oral C) Person-to-person D) Rodents E) Cattle
D - The microbe being discussed here is associated species of Campylobacter. There is no mention in the textbook that this microbe is transmitted through rodents. (See Table 28.2)
A 27 year old female presents to the emergency room with chills, fever, and vaginal bleeding 48 hours after a spontaneous abortion. Upon analysis the patient was determined to have a septic abortion from an infection that was introduced into the uterus, as well as underlying HIV. A blood analysis was performed and high levels of S protein were detected. Which strain(s) of Campylobacter species is this patient most likely suffering septicemia from? A. C. jejuni B. C. coli C. C. upsaliensis/ C. jejuni D. C. fetus E. C. jejuni /C.coli
D - This question is testing on the pathogenesis of Campylobacter species, specifically C. fetus. C.fetus disease nearly always occurs in patients with underlying immunocompromising conditions such as HIV. The ultimate manifestations of C.fetus include systemic infections such as bactermia, septic thrombophelbitis, arthritis, septic abortion, and meningitis. C. fetus is the only member of the Campylobacter family to be covered with a heat stable capsule-like protein (S-protein) that enables it to be resistant to complement and antibody-mediated serum killing.
Which of these organisms causes a disease state when there is consumption of freshly contaminated water, and in extreme cases can cause rapidly fatal diarrhea? A. Vibrio parahaemolyticus B. Aeromonas hydrophila C. Aeromonas caviae D. Vibrio cholerae E. Vibrio vulnificus
D - Vibrio cholerae is the microbe of all of the rest of the choices that matches the description.
A patient has been diagnosed with gastroenteritis. The organism that she is infected by is a gram-negative, comma shaped rod. This species causes vascular infections like bacteremia, arthritis, septic abortion and its common hosts are cattle and sheep. It is resistant to complement-and antibody-mediated serum killing. What is the specific campylobacter species being described above? A. C. jejuni B. C. coli C. C. upsaliensis D. C. fetus E. S. protein
D- C.fetus. C.fetus causes vascular infections like septicemia, septic thrombophlebitis, meningoencephalitis and gastroenteritis because it has the propensity to spread from the GI tract to the blood and distal foci. C.fetus is resistant to complement and antibody mediated serum killing because it is covered with a heat stable capsule like protein called S. protein. This protein prevents C3b from binding to the bacteria and subsequent complement-mediated killing in serum.
Why is it advised to abstain from consuming food or drink prior to being placed under deep anesthesia? A. The possibility of developing muscle dystrophy. B. Achalasia could occur. C. Could lead to a damaged protective gastric mucosal barrier. D. The reflex mechanism of swallowing becomes blocked. E. The esophagus becomes spastically contracted and leads to complications
D- During deep anesthesia gastric material can move from the stomach to the pharynx. Given anesthesia's role in blocking the reflex mechanism of swallowing, the vomited material can be sucked into the trachea leading to aspiration.
Which of the following is true regarding autonomic stimulation of alimentary (GI) tract glandular secretion? A. Parasympathetic stimulation of the alimentary tract inhibits glandular secretion. B. Sympathetic stimulation of the alimentary tract always promotes glandular secretion. C. Autonomic stimulation always stimulates alimentary tract secretion. D. Parasympathetic stimulation of the alimentary tract promotes glandular secretion. E. Sympathetic stimulation of the alimentary tract only occurs when parasympathetic stimulation is absent.
D. (answer found on page 808) - Parasympathetic stimulation "almost invariably" increases the rate of alimentary tract glandular secretion.
The hormone released by S cells in the mucosa of the duodenum and jejunum stimulates copious secretion of what substance? A. Pancreatic enzymes B. Bile C. Glucagon D. Bicarbonate ions E. Insulin
D. (answer found on pages 816-817) - The S cells in the mucosa of the duodenum and jejunum contain the inactive form of secretin, prosecretin, which is released and activated into secretin when stomach chyme dips below a pH of 4.5 to 5.0. Secretin stimulates copious secretion of bicarbonate ions, which neutralize acidic stomach chyme.
A 34-year-old woman presents to the clinic after reporting having fatty stools, indigestion, and cramps for about a week. The physician believes there may be a disruption in the production of enzymes needed to digest triglycerides causing malabsorption. Which of the following enzymes is the most important enzyme for digestion of triglycerides? A. Lingual lipase B. Bile C. Enteric lipase D. Pancreatic lipase E. Elastase
D. (page 826) - Pancreatic lipase is the most important enzyme for digestion of the triglycerides. It is present in such enormous quantities in the pancreatic juice that it can digest all triglycerides it can reach within 1 minute. It splits the triglycerides into free fatty acids and 2-monoglycerides.
A scientist is creating a new drug that inhibits the ileum and large intestines from secreting bicarbonate (HCO3-) and absorbing chloride ions (Cl-). If successful what would this drug most likely interfere with? A. The effects of aldosterone. B. The absorption of nutrients through SGLT1 and GLUT2 co-transporters. C. The digestion of fats through emulsification. D. The neutralization of acid products formed by bacteria. E. The function of Kerckring folds.
D. (pages 828-829) - The epithelial cells on the surfaces of the villi in the ileum, as well as on all surfaces of the large intestine, have a special capability of secreting HCO3− in exchange for absorption of chloride ions. This capability is important because it provides alkaline HCO3− that neutralizes acid products formed by bacteria in the large intestine.
A 69 year-old male patient presents to the Emergency Room with nausea, vomiting, bouts of severe abdominal pain and very frequent episodes of watery diarrhea. Patient reports that he has experienced 11 episodes of diarrhea within the past 5 hours and goes on to confirm that there was no blood in his stool. Through further history and physical examination, the ER physician is correct in deducing the diarrhea and secondary symptoms are viral in origin and starts the patient on IV fluids. Which IV fluid did the physician order for the patient? A. Pure Water B. D5W C. Half Normal Saline D. Lactated Ringer's Solution E. ⅔ D5W, ⅓ Normal Saline
D. Lactated Ringer's Solution is the only answer because the composition of fluid and electrolyte loss from the massive diarrhea consisting of 11 episodes is similar to the composition/electrolytes of the Lactated Ringer's Solution, making it the best option to assist in achieving normal fluid balance.
An 8-year-old patient arrives to the clinic with his mother with complaints of bloody diarrhea. He and his mother had just returned from Kansas while visiting extended family on their farm. His mother notes that he has eaten the same foods as the rest of the family, except for drinking fresh milk when he was helping his uncle with farm chores. The physician suspects a Campylobacter infection. What clinical feature is most likely not associated with Campylobacter jejuni? A. Traveler's diarrhea B. Reactive arthritis C. Fever D. Dysentery E. Pharyngitis
E (Answer found on page 789) - Pharyngitis is an extraintestinal symptom of a Yersinia infection.
A 30 year old woman is admitted to her local hospital after presenting to the ED with abrupt onset diarrhea, vomiting, and severe dehydration. While admitted, her care team is careful to note any signs of metabolic acidosis and hypokalemia. There has been a community-wide increase in similar cases and infectious disease is concerned there may be an outbreak. Which of the following criteria sufficiently indicates an epidemic strain as the cause of these cases? A. Contamination occurs only in warm months B. The strain originate in contaminated water C. Hyperinfectivity is lost within 24 hours of shedding D. Contamination occurs year-round E. The strain is monoclonal
E - Epidemic strains are monoclonal, therefore they initiate disease via specific virulence factors. Exposure must be due to the specific clone responsible for the disease in order to be an epidemic strain. The question stem implicates V. cholerae as the causative agent of the outbreak.
A 32-year-old male patient arrives to his PCP and explains that he is experiencing acute diarrhea and some unexplained weight loss. Upon further questioning the physician learns that the patient went camping with his friends for his bachelor party last month. The physician orders a stool sample and diagnoses the patient with the most common parasitic pathogen in humans. What pathogen was this patient infected with? A. Trichuris trichiura B. Enterobius vermiculari C. Taenia solium D. Plasmodium falciparum E. Giardia lamblia
E - Giardia lamblia is the most common parasitic pathogen in humans and is spread by fecally contaminated food and water. Infection can occur after ingestion of as little as 10 cysts. Due to the cysts' ability to remain resistant to chlorine, Giardia is known to be endemic in public water supplies that are unfiltered. Campers may be infected with Giardia while using rural streams as a source of water or accidentally swallowing water while swimming in contaminated areas.
A four-year-old child comes home from daycare on Friday feeling unwell, with symptoms of watery diarrhea. By Sunday, stool contents now contain blood and leukocytes, and the parents report that there is also significant straining during defecation. The child is diagnosed with shigellosis caused by S. sonnei, and the parents later find out that there was an outbreak at the daycare. What is the most likely route of transmission of shigellosis? A. Zoonosis B. Respiratory transmission C. Flea vector D. Traumatic inoculation E. Fecal-oral
E - The most likely route of transmission of shigellosis caused by Shigella is fecal-oral. Shigellosis is transmitted by direct contact between people, usually due to fecal matter and bacteria on unwashed hands. Otherwise, it is spread indirectly through consuming contaminated food products or water. Nonetheless, shigellosis spreads quickly due to a low infectious dose and poor hygiene in places like daycares.
A 16 year old female arrives at the ER stating that she is experiencing severe motion sickness leading to vomiting, after riding multiple rollercoasters in Universal Studios, Orlando. It is well known that rapidly changing direction/rhythm of motion of the body can lead to some patients experiencing vomiting. What is the correct order of the following phenomenon mechanism? A. The impulses are transmitted mainly via the cerebellum to the vestibular nuclei into the brainstem, to the chemoreceptor trigger zone, to the vomiting center causing the vomiting. B. The impulses are transmitted mainly via the brain stem, to the chemoreceptor trigger zone, to the vestibular nuclei into the cerebellum then to the vomiting center causing the vomiting. C. The impulses are transmitted mainly via brainstem to the vomiting center, to the vestibular nuclei into the cerebellum, and to the chemoreceptor trigger zone causing the vomiting. D. The impulses are transmitted mainly via the cerebellum to the vestibular nuclei into the brainstem, to the vomiting center and to the chemoreceptor trigger zone causing the vomiting. E. The impulses are transmitted mainly via the brainstem to the vestibular nuclei into the cerebellum, to the chemoreceptor trigger zone, to the vomiting center causing the vomiting.
E- The following phenomenon is from vomiting caused by nervous signals of the brain leading to the mechanism called the chemoreceptor trigger zone for vomiting. This mechanism can be caused by motion sickness, the following answer displays the correct order of the mechanism.
A patient has been suffering from gastritis. A monoclonal immunoassay for H. pylori antigens excreted in the patient's stool was ordered and returned positive for the presence of H. pylori antigens. What is the most effective treatment course for this patient? A. Nothing, H. pylori infection is self limiting. B. Antibiotic C. Bismuth + Antibiotic D. Proton pump inhibitor E. Proton pump inhibitor + Antibiotics
E- The greatest success in curing gastritis or peptic ulcer disease has been accomplished with the combination of a proton pump inhibitor (e.g., omeprazole), a macrolide (e.g., clarithromycin), and a β-lactam (e.g., amoxicillin).
When high-protein food is consumed and reaches the antral end of the stomach, which cells are stimulated, and what do they release? A. Parietal cells are stimulated to release intrinsic factor into the stomach B. Enterochromaffin-like cells (ECL cells) are stimulated to release gastrin into the blood C. G cells are stimulated to directly release hydrochloric acid into the stomach D. Parietal cells are stimulated to release pepsinogen into the stomach E. G cells are stimulated to release gastrin into the blood
E. (answer found on pages 813-814) - G cells are stimulated to release gastrin; meats and other foods containing protein contain specific proteins that stimulate gastric cells (G cells) to release gastrin into the blood. Gastrin then stimulates ECL cells to release histamine into oxyntic glands. Histamine acts on the parietal cells in oxyntic glands to stimulate the release of gastric hydrochloric acid.
The final products of carbohydrate digestion are all water soluble monosaccharides that are absorbed immediately into the portal blood. Which pairing of intestinal epithelial enzyme/end product is INCORRECT? A. Lactase → galactose B. Sucrase → fructose C. Maltase → glucose D. 𝞪-dextrinase → glucose E. All of these answer choices are correct
E. (page 824) - All of these pathways are correctly associated with each other
A 29-year-old female presents to the ED with nausea, vomiting, and diarrhea. Her medical/surgical history is significant for having underwent a medically induced abortion six days ago. The patient's blood pressure falls to 80/40 and is rushed to the operating room where she dies. A pathology report of her uterine tissue is done and comes back with DNA from a gram-positive organism that is anaerobic and rod-shaped. What is the most likely organism that took host in this woman's uterus? A. Toxic shock syndrome from Clostridium tertium is the most likely cause as this woman ingested soil during her pregnancy B. Because of the stress of her abortion, this woman's immune system is compromised and Gardnerella vaginalis of her vaginal microbiome took host and caused a septic infection C. The instruments used during her abortion were likely contaminated with Staphylococcus aureus leading to her subsequent septic infection D. The woman lost so much fluid from her uncontrolled diarrhea that her blood pressure dropped due to an infection with Giardia lamblia E. Toxic shock syndrome is likely the cause of death from Clostridium sordelli as this is associated with abortions
E. This woman's medical history is significant for having an abortion 6 days ago. Clostridium sordelli is a gram positive, rod-shaped, anaerobe that is associated with causing toxic shock syndrome in abortions.
