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