Chapter 3: infectious diseases

Hutchinson's Triad

1. Hutchinson's incisors and mulberry molars 2. Ocular interstitial keratitis 3. Eighth cranial nerve deafness

What percentage of deaths are caused by infectious diseases?

20% globally

How does the body respond to becoming infected with TB?

A person's initial exposure causes a localized, chronic inflammatory reaction in the lungs called primary TB. The body creates a physical, granulomatous barrier that walls off the bacteria but is unable to destroy or remove it. That is "latent TB"

does scarlet fever cause "white strawberry tongue" or "red strawberry tongue"?

It starts off as "white strawberry tongue" and after 4 or 5 days the white coating disappears to reveal an erythematous surface underneath known as "red strawberry tongue."

What organism causes leprosy?

Mycobacterium leprae. Leprosy is not very contagious and has a long incubation period. The exact mode of transportation is unknown. individuals are considered no longer contagious after 2 weeks of antibiotics.

How does someone become a carrier?

Some individuals immune systems neither eliminate the agent nor become ill. in this case, the person becomes a carrier.

Streptococcal Pharyngitis

Strep throat is most common in children ages 5 to 15 and is usually spread by direct contact. group A beta-hemolytic streptococci are responsible for up to 30% of acute cases in children.

What is the etiologic agent responsible for the clinical characteristics of scarlet fever?

The clinical features are a result of a toxin produced by group A beta-hemolytic streptococci, which preferentially attacks blood vessels rather than infection of the tissues themselves.

what are the clinical features of Actinomycosis?

The most common location for cervicofacial Actinomycosis is the soft tissue overlying the angle of the mandible. The suppurative phase of the infection shows yellow flecks or sulfur granules. The fibrotic "wooden" nature of affected areas makes it difficult for antibiotics to penetrate.

Thrush

The pseudomembrane candidiasis plaques can be wiped off with a dry gauze. Underlying mucosa may be erythematous but in tact. This clinical representation is often referred to as thrush.

True or false: Actinomycosis is caused by a bacteria that is part of the normal oral microflora.

True! Actinomyces israelii is part of the microflora and and can cause disease when they gain entry via injury or break in local barrier such as through an extraction socket, soft tissue trauma, nonvital tooth, or a blow to the jaw.

zoonotic infection

a disease that normally exists in animals but that can infect humans. an example is lyme disease

Leprosy, "Hansen's Disease"

a granulomatous infectious disease characterized by disfiguring skin lesions, nerve damage, upper respiratory mucosal lesions, and progressive debilitation.

what is a helminth?

a parasitic worm; a fluke, tapeworm, or nematode.

Tuberculosis

a potentially life-threatening infection caused by Mycobacterium tuberculosis. TB infection is not synonymous with TB disease.

Scarlet fever

a systemic infection that most often occurs secondary to Streptococcal Pharyngitis (strep throat) characteristics include: white coating on dorsal of tongue, papillae become hyper plastic, and classic skin rash.

impetigo

a very contagious superficial skin infection caused by Streptococcus pyogenes and/or Staphylococcus aureus. can develop in an area where skin was damaged and spreads rapidly. has 2 forms - nonbullous and bullous

Vincent's infection

another name for NUG. also called trench mouth. microorganisms are usually resident microflora that become proliferative and invasive during a change in nutrient availability.

what facilitates in transmission of infectious diseases?

antibiotic resistance and increased air travel

what are indigenous microflora?

are present at birth. usually protective organisms but can sometimes become pathogenic with change of host environment.

bacteria

are single celled microorganisms that contain DNA but no nucleus. Three shapes include cocci, bacilli, and spirochetes.

protozoa

are single celled organisms that are either free living or parasitic. Protozoa have complex strategies for avoiding immune recognition

Cat-scratch disease

cat's are natural reservoirs of the causative organism, Bartonella henselae. No person to person transmission has been documented. This disease is the most common cause of regional lymphadenopathy in children. swelling occurs 3 weeks after contact.

what is an opportunistic infection?

caused by microorganisms that usually do not produce disease in a person with a healthy immune system. When an immune system is compromised in some way these microorganisms may cause disease.

Noma "cancrum oris"

comes from Greek word meaning "to devour." classically develops after measles or another significant acute illness. Noma progresses rapidly, the mortality rate is significant and survivors will suffer major facial disfigurement.

dysphagia

difficulty swallowing

diphtheria

diphtheria is a potentially fatal infection caused by Corynebacterium diphtheria. The organism is transmitted through direct contact and produces a deadly exotoxin that results in spreading tissue necrosis.

tertiary syphilis

during the latent phase about 30% of patients will progress to tertiary syphilis, the most serious stage. Complications of the vascular system such as, aortic aneurysm and congestive heart failure.

When are opportunistic infections common?

especially common in patients with immunosuppressive conditions such as AIDS.

extra-pulmonary lesions of TB

extra-pulmonary lesions are possible and can occur in any organ. Oral lesions are rare and usually present as a painless, non healing ulcer with rolled borders, non unlike squamous cell carcinoma.

congenital syphilis

fetal infection during latent syphilis results in a child born with congenital syphilis. untreated infants who survive develop tertiary syphilis, which affects the CNS, eyes, ears, bones, and teeth.

gumma

found with tertiary syphilis. active sites of granulomatous inflammation called gummas may cause significant tissue destruction and can be seen throughout the body.

intra-oral gumma

found with tertiary syphilis. are most often found on the tongue or palate. palatal lesions can cause perforation into the nasal cavity.

what are the physical characteristics of congenital syphilis?

frontal bossing, high-arched palate, saddle-nose deformity, and hutchinson's triad.

How long does it take for signs and symptoms of secondary syphilis to resolve?

generally 3 to 12 weeks.

what are constitutional symptoms?

group of symptoms that can affect many different systems of the body. symptoms include fever and malaise

Maladies caused by pathogenic microorganisms are termed ______ _____?

infectious diseases

what is keratitis?

inflammation of the cornea of the eye.

what are the symptoms of diphtheria?

intra-orally, a thin yellow exudate forms over the tonsils and evolves into an adherent necrotic membrane. Eventually, the pseudomembrane becomes green or black in color and may spread to soft palate and larynx. Myocarditis, neuropathy, and airway obstruction can occur.

Actinomycosis

is an opportunistic infection caused by Actinomyces israelii. The bacteria are found ubiquitously in tonsillar crypts, carious lesions, oral biofilm, and calculus.

Pseudomembrane Candidiasis

it is characterized by adherent white "cottage cheese-like" plaques that consist of C. albicans organisms, superficial epithelial cells, and debris.

maternal transmission of syphilis

maternal transmission of T. palladium to the fetus during primary or secondary syphilis usually results in miscarriage, stillborn, or birth defects.

What causes infectious diseases?

microorganisms that include bacteria, viruses, fungi, prions, protozoa, helminths, and anthropods.

Erythematous Candidiasis

more common than pseudomembranous, but may be more challenging to diagnose. Acute atrophic candidiasis is a symptomatic

what is the gray pseudomembrane in NUG composed of?

necrotic debris. it also is accompanied by intense pain and a foul odor.

Do individuals with latent TB become ill?

no, they do not become ill and cannot transmit TB to others. Active TB disease develops only in 5 to 10% of infected individuals.

Latent syphilis

occurs after secondary syphilis symptoms resolve. a symptom-free and lesion-free period that may last anywhere from 1 to 30 years. with the exception of mother-to-fetus transmission, individuals are unlikely to infect others.

Primary syphilis

occurs upon infection with T. pallidum. a painless ulcer called a chancre develops at anatomical site of exposure. This may occur anywhere from 3 days to 3 months after exposure and is accompanied by regional lymphadenopathy.

What are the most common infectious agents in the oral cavity?

periodontal and cariogenic microorganisms

cutaneous diphtheria

presents as non healing skin ulcers and can even occur in vaccinated patients. The diagnosis should be kept in mind for patients who have recently traveled to countries where diphtheria is endemic.

Bacterial cell wall

primarily made of peptidoglycan molecules. Gram positive bacteria have a thick wall whereas gram negative have a thin wall with a surrounding layer of lipopolysaccharide and a lipoprotein outer membrane.

secondary syphilis

secondary or disseminated syphilis may develop anywhere from 4 to 10 weeks after primary infection. This stage is more contagious than primary and is characterized by macro-papular skin rash on palms and soles.

Secondary TB

secondary tuberculosis is a reactivation of the dormant infection, usually in patients who become immunosuppressed, elderly, or develop other debilitating chronic diseases.

erysipelas

skin infection caused by Streptococcus, affecting the deep epidermis with extension into the lymphatic system. sometimes a red streak can be seen extending to the lymph node. warm, swollen, erythema with sharp border.

what is a convalescent carrier

someone who has passed the clinical stage of the disease but can still transmit it

what is an incubator carrier

someone who is infected but is not yet showing clinical signs. this is the prodromal period

bullous impetigo

sometimes called "staphylococcal scalded skin syndrome" it usually occurs in infants and newborns involved areas develop large bullae that become purulent and then rupture to be covered by a thin brown crust.

What are the symptoms of secondary syphilis?

symptoms are nonspecific and include fever, headache, body aches, lymphadenopathy, and malaise. Mucous patches on the oral mucosa appear in about 30% of patients and appear as tender white mucosa.

Syphilis

syphilis is an infection caused by a spirochete called Treponema pallidum. It progresses through 3 clinical stages referred to as primary, secondary, and tertiary. Patients are very contagious during primary and secondary stages.

how could antibiotic use effect microflora?

systemic antibiotic therapy may inadvertently eliminate some of the protective microflora, allowing overgrowth of other bacteria that in small numbers are of low pathogenicity.

pathogenicity

the ability of a microorganism to produce pathological changes or disease.

selective toxicity

the goal of all antimicrobial therapy. meaning that the drug should affect the microbe and not the host.

nonbullous impetigo

the more common form and typically develops in school-aged children. also referred to as impetigo contagiosa. lesions begin as red papules and later form blisters that rupture and become covered by a thick amber colored crust.

Candidiasis

the most common superficial fungal infection seen in the oral cavity. It also has been called candidosis and moniliasis. There are 40 known species of Candida.

define etiological agent (infectious agent)

the specific microorganism that causes the disease. example: the etiological agent of tuberculosis is the bacterium Mycobacterium tuberculosis.

all current available antivirals are viralstatic. what does this mean?

viralstatic means that they target viral enzymes involved in nucleic acid or protein synthesis and stop replication.