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Doctors In Training
DIT questions for USMLE Step 1
Question | Answer |
---|---|
What would expect to find in a pt with a lesion of CN XII? CN X? | -Difficulty swallowing & speaking -CN XII tongue deviates towards side of lesion -CN X tongue deviates away from side of lesion |
What are some of the distinctive clinical features of Williams syndrome? | -Congenital micro-deletion of long arm of chromosome 7 (deleted region includes Elastin gene) -Distinctive “elfin” facies, mental retardation, well-developed verbal skills, cheerful disposition, extreme friendliness with strangers, cardiovascular problem |
On which cells would you find CD3 molecules? On which cells would you find CD4 molecules? To what do CD4 molecules bind? On which cells would you find CD8 molecules? To what do CD8 molecules bind? | - CD3 complex – cluster of polypeptides associated with a T-cell receptor - CD4 – helper T cells, bind MHC II on antigen-presenting cells - CD8 – cytotoxic T cells, bind MHC I on virus-infected cells |
What causes the S1, S2, S3, and S4 heart sounds? | S1 – tricuspid & mitral S2 – aortic & pulmonic S3 – early diastole during rapid ventricular filing ; increased filling pressures & dilated ventricles (normal in children) S4 – “atrial kick” – late diastole; high atrial pressure; ventricular hypertrophy |
Name five or more drugs that inhibit acetylcholinesterase. What is the clinical application for each? | -Neostigmine → post-op & neurogenic ileus, urinary retention,MG,NMJ blockade reversal - Pyridostigmine → MG (long acting); no CNS - Edrophonium → Dx MG (v short acting) - Physostigmine → glaucoma (crosses BBB → CNS) & atropine OD -Echothiophate → glau |
What are the main differences between nephritic syndrome and nephrotic syndrome? | -Nephritic = inflammatory process involving glomeruli, leading to hematuria, azotemia, RBC casts in urine, oliguria, hypertension, & proteinuria (< 3.5 g/day) -Nephrotic - presents with massive proteinuria (> 3.5g/day, frothy urine), hyperlipidemia, edem |
What are the acidic and basic amino acids? Where can you find high concentrations of basic amino acids? Why are these amino acids found in these areas? | Acidic amino acids – Asp & Glu Basic amino acids - Arg, Lys, & His Arg & Lys are increased in histones, which bind negatively charged DNA |
What bacteria are known for causing bloody diarrhea? | Campylobacter, Salmonella, Shigella, Entero-hemorrhagic E. coli, Entero-invasive E. coli, Yersinia enterocolitica, C. difficile (both watery & bloody) |
What nerve injury would you suspect in a pt with the following motion deficits? •foot drop (loss of dorsiflexion) •loss of plantar flexion •loss of knee jerk •loss of hip adduction | •foot drop (loss of dorsiflexion) → Common peroneal •loss of plantar flexion → Tibial •loss of knee jerk → Femoral •loss of hip adduction → Obturator |
What are the leading causes of death in infants? | Volume of distribution (Vd) = amount of drug in the body / plasma drug concentration - Low Vd (4-8L) distribute in blood - Medium Vd distribute in extracellular space or body water - High Vd (> body weight) distribute in tissues |
What are the clinical features of hyperammonemia? | Tremor, slurring of speech, somnolence, vomiting, cerebral edema, blurring of vision |
What changes in sleep patterns and sexual anatomy are seen in the elderly? | - Sleep patterns – decr. REM sleep, decr. Slow-wave sleep, incr. sleep latency, incr. awakenings during the night - Men – slower erection/ejaculation, longer refractory period - Women – vaginal shortening, thinning & dryness |
Describe the probe and sample to which the probe binds in the following molecular biology techniques: Southern blot, Northern blot, and Western blot. | Southern blot = Labeled DNA probe binds DNA sample Northern blot = Radioactive DNA probe binds sample RNA Western blot = labeled antibody binds sample protein |
What are the diagnostic criteria for major depressive episode? What changes in sleep patterns are seen in pts with depression? | Sleep Loss of interest (anhedonia) Guilt Low energy Cognition/conc. Appetite change Psychomotor retardation Suicidal Sleep patterns: Decr slow wave sleep, Decr REM latency, Incr REM early in cycle, Incr total REM, Repeated & Early-morning awake |
What is the clinical definition of chronic bronchitis? | (“Blue Bloater”) - Productive cough for > 3 consecutive months in >2 years. Disease of small airways |
Which neoplasm is most commonly responsible for the hormone paraneoplastic syndrome? -ACTH → Cushing’s syndrome -PTH-related peptide → hypercalcemia -erythropoietin → polycythemia -ADH → SIADH | -ACTH - small cell lung carcinoma -PTH-related peptide - squamous cell lung, renal cell, & breast carcinoma -erythropoietin - renal cell carcinoma, hemangioblastoma -ADH – small cell lung carcinoma & intracranial neoplasms |
What is the blood supply to the embryonic foregut, midgut, and hindgut? What adult structures arise from these primitive guts? | - Foregut – Celiac a. → Stomach to proximal duodenum; liver, gallbladder - Midgut – SMA → distal duodenum to proximal 2/3 of transverse colon - Hindgut – IMA → distal 1/3 of transverse colon to upper portion of rectum; splenic flexure is watershed regio |
Which tract of the spinal cord relays sensory information from the body? Which tract relays pain and temperature sensation? Which tract relays motor sensation to the body? | Sensory info – dorsal column – medial lemniscal pathway Pain & temp sensation – spinothalamic tract Motor sensation to body – lateral corticospinal tract |
What is most common tumor of the salivary gland? What is the most common malignant tumor? | Most common tumor is pleomorphic adenoma of parotid gland Most common malignant tumor is mucoepidermoid carcinoma |
What is the difference between a case-control study, a cohort study, and a clinical trial? (FA p60) Which studies use odds ratios, and which use relative risks? | Case control study – Compares a group of people with disease to a group without - Uses odds ratio (OR) Cohort study – Compares a group with given risk factor to a group w/o whether the risk factor increases likelihood of disease -Uses relative risks (R |
Three days ago you hospitalized a 40-year-old male for myocardial infarction. He has been given all of the usual medications. Today you notice that his platelet count is 30,000. What do you suspect is the cause of his low platelets? | Heparin-induced thrombocytopenia – heparin binds to platelets, causing autoantibody production that destroys platelets & over-activates remaining ones, resulting in thrombocytopenic, hypercoagulable state |