UWorld
Histological features of Hypertrophic cardiomyopathy
(MCC of SCD) Massive myocyte hypertrophy = septal region predominantly affected Myofiber dissaray Abnormally shaped myocytes with bizarre nuclei
Odds ratio equation
(using 2x2 table) = [a/c] / [b/d] = [axd] / [bxc] *probability of event happening / propbability of event not happening* = odds that the disease were exposed / odds that the controls were exposed = why this is used in case-control because it is retrospective
Relative risk equation
(using 2x2 table) [a/a+b] / [c/c+d] = exposed / unexposed = probability of getting disease if exposed / probability of getting disease if not exposed [why this is used in cohort!]
Branches of the gastroduodenal
- Right gastroepiploic (pyloric end of greater curvature of stomach) - Superior pancreaticoduodenal arteries (head of pancreas)
At what level is a type 1 error preset?
0.05
Branches of the superior mesenteric artery
1. Inferior pancreaticoduodenal 2. Intestinal arteries (jejunum and ileum + form vascular arcades and vasa recta at gut wall) 3. Ileocolic artery (distal ileum and cecum) 4. Right colic (ascending colon) 5. Middle colic (proximal 2/3rds of transverse colon)
Drug classes for glaucoma that work on: 1. Trabecular outflow 2. Uveoscleral outflow 3. Aqueous humor production / secretion
1. Muscarinic agonists 2. Prostaglandin agonists 3. Beta blockers, alpha 2 agonists, carbonic anhydrases
When does differentiation and development of the external genitalia occur?
8-15 weeks of gestation
Confidence coefficients for: 90% CI 95% CI 99% CI
90% CI - 1.64 95% CI - 1.96 99% CI - 2.58
Paraventricular nucleus of the hypothalamus function
ADH CRH TRH Oxytocin
Supraoptic nucleus of the hypothalamus function
ADH Oxytocin
Role of transcriptional modification in huntington disease
Abnormal huntingtin causes increased histone de-acetylation = silences genes necessary for neuronal survival (Acetylation normally increases gene transcription)
Type 2 error (beta error)
Accepting null when it is false saying there is no association when there is one
Pathology behind LEMS
Antibodies against voltage gated calcium channels = involved in acetylcholine release
Marginal artery
Branches of SMA and IMA = interconnected = provides collateral circulational if there is a vascular obstruction in some part of the SMA and IMA
ANOVA use
Checks difference between means of 3 or more *ANalysis Of VAriance = this is 3 words = therefore 3 or more means
Suprachiasmatic nucleus of the hypothalamus function
Circadian rhythm regulation Pineal gland function
What is a case control study?
Compares a group of people with disease to one without disease = looks for prior exposure or risk factor = RETROSPECTIVE MOSTLY
When is a highly specific test used?
Confirmation after a positive screening test
Chi-square use
Difference between 2 or more proportions of categorical outcome (NOT mean values)
Dilated cardiomyopathy - characteristics of heart - associated with?
Dilation of all chambers of enlarged heart Flabby heart Associated with mural thrombus
What is lead time bias?
Early detection is confused with increased survival
How can one avoid selection bias?
Ensure choice of the right comparison/reference group Randomization
What causes epispadiasis?
Faulty positioning of genital tubercle (5th week) note: genital tubercle = dorsal surface of penile shaft in females = forms clitoris
How do you know if a CI is significant or not?
For Odds ratio / relative risk: If the CI includes 1 then there is NO significant difference and the null is ACCEPTED For mean difference: if CI includes 0 then no significant difference, null is ACCEPTED
Branches of the left gastric
Gastric branches - less curvature Esophageal branches - distal 1 inch of esophagus
What is a cohort study?
Group exposed to risk factor identified and followed and compared to group not exposed to risk factor = INCIDENCE = Looking FUTURE
Posterior nuclei of the hypothalmus function
Heat conservation
Anterior nuclei function of the hypothalamus
Heat dissipation
Destruction of ventromedial nucleus
Hyperphagia
Destruction of the anterior nuclei leads to?
Hyperthermia
What happens if there is incomplete fusion of the urethral folds
Hypospadiasis
Destruction of the posterior nuclei will lead to?
Hypothermia think: POsterior HyPOthermia
Alternate hypothesis
Hypothesis of some difference or relationship there is an association between disease and risk factor
What cannot be assessed using case-control studies?
Incidence or prevalence = must used ODDS RATIO case control = determines causal relationships
Suprior pancreaticoduodenal arteries anastamose with what?
Inferior pancreaticoduodenal brances of superior mesenteric arteries
Small vs large SD
Large - observations = widely spread out Small - closely centered around the mean
If there is an aneurysm of the SMA what can be compressed?
Left renal vein
Positive Skew
Mean>Median>Mode Tail long on right
T-test use
Means of 2 groups (Think: Tea is meant for 2)
Pulmonary capillary wedge pressure readings
Measures left atrial pressure
Ventromedial hypothalamic nuclei function
Mediates satiety
Morbidity rate vs. mortality rate
Morbitidy = rate of disease in a population Mortality = rate of death in a population
Right renal artery passes where?
Posterior to IVC
What is a cross-sectional study?
Presence or absence of disease = determined in each member of the study population Assessing frequency of disease Exposure and outcome are measured simultaneously at a particular point in time. --> DISEASE PREVALENCE
What does a cross-sectional study measure?
Prevalence
P value
Probability that the findings observed could have occurred d/t chance if less than 0.05 then p value is statistically significant
What is prevalence of a disease?
Proportion of people in a population with a particular disease = ALL individuals affected by these
Sensitivity
Proportion of people who really do have a disease SN-N-Out = Highly sensitive test when negative rules out disease
Specificity
Proportion of people without the disease SP-P-IN = Highly specific test rules IN disease
Relative risk reduction Equation
Proportion of risk reduction attributable to an intervention ie. % of people getting the flu without a flu shot vs getting the flu with the flu shot RRR = 1 - RR
Measure for cohort study
Relative Risk
Standard deviation equation
Square root of variance
Cause for left ventricular outflow obstruction in HCM
Systolic anterior motion of mitral valve toward interventricular septum
Null Hypothesis
There is no difference or relationship no association between disease and risk factor in the population
Branches of the splenic artery
Think: SPLeen 1. *S*plenic branches 2. *S*hort gastric (fundus) 2. branches to *P*ancreas (body and tail) 4. *L*eft Gastroomental aka gastroepiploic (greature curvature)
When are highly sensitive tests used?
To screen for diseases with low prevalence
RNA polymerase III role
Transfer RNA
Bimodal distribution suggests?
Two different populations
Metabolic effects of second generation anti-psychotics
Weight gain Dyslipidemia Hyperglycemia [quetiapine, olanzapine, risperidone, aripiprazole, ziprazodone]
Penile raphe role
anterior wall of urethra
RNA Polymerase II
makes: mRNA, microRNA, small nuclear RNA (mRNA splicing)
Signs of botulinum toxin infestions
Diplopia Dysphagia Dysphonia 3 D's
Standard error of the mean
SD / square root of sample size - estimate of how much variability exists between the sample mean and the true population mean
Arcuate nucleus of the hypothalamus function
Secretion of: dopamine (inhibits prolactin) ghrh gnrh
Gondal arteries descend where?
Psoas major muscle (ventral)
RNA polymerase I role
rRNA = functions in nucleolus (note: also site for maturation and assembly of ribosomal subunits: synthesized in the cytoplasm and transported in nucleolus)
What causes the SEM to decrease?
Increasing n (Sample size)
Equation for incidence
# of new cases / # people at risk
Equation for prevalence
#existing cases / total #of people in a population
What is absolute risk reduction? Equation
Amount the therapy reduces risk of bad outcome ARR = [c/c+d] - [a/a+b] = Control event rate - experimental event rate
If a physican suspects abuse in a child what is the next step?
Asking permission to interview the child alone *parental refusal to allow the child to be interviewd alone is concerning for abuse
Type 1 error (alpha error)
Assuming there is a significant association when there is none = rejecting null when it is true
What is attributable risk? Equation
DIFFERENCE between exposed and unexposed groups [a/a+b] - [c/c+d]
How does random error affect the precision of the test
Decreases it (precision = reliability)
What is meant by myxomatous changes?
Pathologic weakening of connective tissue
When are the following arteries subject to erosion: a. splenic b. left gastric c. gastroduodenal
a. ulcer of posterior wall of stomach b. ulcer of lesser curvature c. ulcer of posterior wall of first part of duodenum
Destruction of the lateral nuclei leads to?
Anorexia
Branches of the inferior mesenteric artery
1. Left colic (Distal third of transverse colon and descending colon) 2. Sigmoid arteries (sigmoid colon) 3. Superior rectal (superior aspect of rectum and anal canal)
Branches of the celiac trunk
1. Left gastric 2. Splenic artery 3. Common hepatic artery
Branches of Common hepatic
1. Proper hepatic 2. Gastroduodenal
Branches of the proper hepatic
1. Right gastric 2. Right hepatic --> cystic artery (gallbladder) 3. Left hepatic
Mutation in HCM
Beta myosin heavy chain Myosin-binding protein C
How does one decrease beta?
By increasing power = increasing sample size = increasing expected effect size = increasing precision of measurement *note: the study is said to be high quality when the power of the test is 0.8 or higher
3 main arteries for the GI tract
Celiac trunk Superior mesenteric artery Inferior mesenteric artery
How are precision and standard deviation related?
Increase precision decrease standard deviation
How are precision and statistical power related?
Increase precision, increase statistical power
What structures arise from neural crest cells?
MOTEL PASS Melanocytes Odontoblasts Tracheal cartilage Enterochromaffin cells Laryngeal cartilage Para-follicular cells of the thyroid Adrenal medulla Schwann cells Spiral membrane
Fusion of urethral folds in male vs female fetuses
Male: forms ventral aspect of penis + penile raphe Female: Do NOT fuse = form labia minora
Labioscrotal folds form what in males vs. female fetuses
Males = scrotum Females = labia majora
Negative skew
Mean < Median < Mode Tail long on left
What is the incidence of a disease?
Measurement of the number of NEW ppl who contract a disease during a particular time period
Lateral hypothalamic nuclei function
Mediates hunger
Number needed to harm
Number of patients who need to be exposed to a risk factor for 1 patient to be harmed NNT = 1/ AR
Number needed to treat
Number of patients who need to be treated for 1 patient to benefit NNT = 1/ARR
S/S of Lambert-Eaton Myasthenic syndrome (LEMS)
Proximal muscle weakness (difficulty climbing stairs, getting up from a chair) Ptosis Diplopia Dysarthria/dysphagia Dry mouth Impotence **get better with repetitive stimulation vs. myasthenia gravis get worse
Signs of childhood abuse
Retinal hemorrhages Genital trauma Swelling, bony tenderness Presence of multiple injuries in different stages of healing Behavioural disturbances (Excessive compliance, pseudo-maturity)
Triad for Whiskott-Aldrich syndrome What is the mutation?
Think: WATER: *W*iskott-*A*ldrich, *T*hrombocytopenia *E*xcema* *R*ecurrent infections +increased risk of autoimmune dz and malignancy WAS gene = t cells unable to reorganize actin cytoskeleton
When are Odds ratio and Relative risk equal to one another?
When the INCIDENCE of a disease is low --> ie. with the rare disease assumption [refers to the practice of approximating the odds ratio and relative risk when conducting a *case-control* study for rare diseases
Confidence interval equation
mean +/- Z x (SEM) where Z = confidence coefficient eg. if 95% CI then you are 95% confident the true value is between the range of CI. 99% CI is wider than 95% = if you want to be more confident then you need to give a wider range
