Cards from UWorld Flashcards
What type of symptoms would occur if the artery with the arrow was occluded?
Contralateral leg/foot, urinary incontinence.
this is an ACA stroke
What investigations are helpful when diagnosing tentanus?
No investiagations needed; this is a clincial diagnosis based on hx and PE
Flaccid bullae with ++Nicolsky are assocaited with which condition? What autoantibodies do you expect to find?
Pemphigus vulgaris; anti-desmoglein 1 and 3
What are the symptoms of rabies? How does it enter the host?
Nonspecific flu like symptoms with paresthesias radiating from a known wound progressive to rabies encephalitis (pharyngeal spasms, mental status changes, autonomic dysfunction, muscular rigidity).
Rabies enters the host by binding to nicotinic ACh receptors on the NMJ
How would you differentiate Klebsiella from Pseudomonas ?
Klebsiella is a lactose-fermenting gram-negative rod
Pseudomonas is a non-lactose-fermenting, oxidase-positive, gram-negative rod.
What MEN type is associated with hypercalcemia? What other cancers do you need to screen for?
MEN-1: primary hyperthyroidism, pituitary tumors and pancreatic tumors
What is the diagnosis based on this barium swallow study? What is the most likely cause? What symptoms would you expect to find?
This is a zenker diverticulum; likely caused by cricopharyngeal motor dysfunction.
Symptoms include halitosis, regurgitation and aspiration pneumonias
How is ejection fraction calculated?
(Preload - afterload) / preload
What is the cause of warfarin-induced skin necrosis?
protein C or S deficiency >> depletion leads to microvascular occlusion due to hypercoagulation.
What are the differences between the toxins produced by EHEC, Shigella, Pseudomonas and diptheria?
EHEC and Shigatoxin have A/B subunit -> B binds and lets it in, A blocks tRNA binding to 60S subunit
Pseudomonas exotoxin A and diptheria toxin block elongation factor 2 (EF-2) leading to inability to bind the next tRNA.
What drugs are useful to prevent recurrence of colon cancer?
Low-dose aspirin as a COX-inhibitor; since adenocarcenoma is typically dependent on prostaglandins for proliferation.
What is the difference between a synergistic and a permissive effect?
Synergism requires both drugs to have independent response, whereas in a permissive effect, it can allow an existing drug to exert more of an effect despite the additive not having an effect when dosed on its own.
What is the cause of an IV blanching with induration and pallor when running norepinephrine?
Extravasation / leakage causing alpha-1 activation. Treat with phentolamine (an alpha-blocker).
Where does renal cell carcinoma originate?
The proximal renal tubules
What are the causes of red and white patches in melanoma?
Red - vessal ectasia (dilatation) and inflammation
White - Melanocyte regression due to recognition of neoplastic cells by NK cells.
What bacteria would be positive to pyrrolidonyl arylamidase?
Strep pyogenes (GAS); this test is more sensative than bactracin sensitivity.
What is the effect of beta-blockers on ECG?
Lengthening of the PR interval due to slowing of conduction.
What mutation would result in anti-EGFR resistant colorectal cancer?
activating KRAS mutation (downstream of EGFR)
What is the mechanism of the defect caused by holoprosencephaly?
Incomplete division of the forebrain into the telencephalon and diencephalon (5wks gestation). It is a field defect (multiple malformations) caused by combination of genetic (T13, SHH mutation) and environmental factors.
Which cytokines have anti-inflammatory effects? What cells produce them?
Th2: IL-4 and IL-10
Treg: IL10 and TGF-beta
What are the early and late-phase type 1 reactions on repeat exposure?
Early: igE x-link leading to histamine and leukotrienes: wheal and flare
Late: TH2 cells release IL-5 -> eosinophils -> major basic protein -> tissue damage and induration.
What differentiates induration due to type I and type IV hypersensitivity reactions.
Late-phase type 1 manifests as induration hours after exposure to allergen
Type IV is cell-mediated and takes several days to develop
What drugs require methylation to be bioactivated?
azathioprine and 6-mercaptopurine
What drugs require acetylation for bioactivation?
isoniazid, dapsone, hydralazine, procainamide
What is the arterial supply to the inferior surface of the heart?
right coronary artery > posterior descending artery
What does the left circumflex coronary artery supply?
Lateral posterior and superior walls of LV
What does the left anterior descending artery supply?
Anterior 2/3rds of intervenricular septum, anterior wall of LV and anterior papillary muscle
Midshaft fracture of the humerus would most likely cause what type of neuropathy?
Radial nerve injury leading to wrist drop and sensory loss over posterior forarm and dorsum of the hand.
What are the two locations where the ulnar nerve can be injured?
Medial epicondyle of the humerus or Guyon’s canal near the hook of the hamate and the pisiform bone.
What are the enveloped DNA viruses?
Hepadna (hep B), herpes, pox
what are the non-enveloped DNA viruses?
adenovirus, Papova (HPV), polyoma (JC, BK)
What is the most common cause of colitis in an individual with advanced AIDS? What are the histological characteristics?
CMV reactivation: multiple ulcers, mucosal erosions with large cells with basophilic intranuclear and intracytoplasmic inclusions.
What part of the GI tract is affected by cryptosporidium? What findings on microscopy?
Small intestine – acid fast oocytes in stool. with basophilic parasites on the brush border.
Which viral proteins are affected by HIV protease inhibitors?
gag / pol polyproteins (functional viral proteins)–NOT envelope proteins (env).
What is the most likely diagnosis in this patient who has acute painless vision loss since “a few hours ago”?
retinal artery occlusion
What changes on PFT are expected in the setting of COPD?
Air trapping (obstructive pattern) so higher TLC and higher FRC, lower expiratory and inspiratory reserve volume. RV/TLC increases, FEV1/FVC <0.7
Which autoantibodies would be associated with symmetrical proximal muscle weakness?
ANA; anti-histidyl-tRNA-synthetase (anti-Jo-1); this is polymiositis.
What are the effects of acetazolamide on electrolytes?
Reduced sodium, potassium and bicarbonate.
What are the key features of drug-induced acute interstitial nephritis?
Rash/fever, new drug exposure in last 1-3 weeks
AKI, inflammatory interstitial infiltrate and urinary eosinophils + eosinophilia are characteristic.
What 3 medications are used for anaesthesia induction? What are their pro/s cons
Propofol - GABA-agonist reduces airway resistance and causes vasodilation
Etomidate - GABA agonist hemodynamically neutral but causes adrenocortical suppression (avoid in septic shock)
Ketamine - NMDA antagonist preserves respiratory drive and provides analgesia, increases HR, contractility and cerebral blood flow
what structure represents the division between the anterior 2/3rds and posterior 1/3 of the tongue? what is the sensory innervation respectively? What is the innervation for taste
Terminal sulcus + foramen cecum.
Anterior = sensory V3 (mandibular) and taste chorda tympani branch of CN7.
posterior = sensory + taste glossopharyngeal and vagus at the tongue root.
What infection presents with heterophile antibodies?
Infectious mononucleosis (EBV) - either monospot (horse) or paul-bunnell (sheep).
What is the most important treatment for diptheria?
diptheria antitoxin
What lung lobe is most likely to develop aspiration pneumonia if the patient is standing? supine? prone?
Standing -> basilar segments of lower lobes
Supine -> posterior segment of upper lobs and superior lower lobe segments.
Prone -> middle lobe and lingula
Generally R > L
What are some mechanisms to improve drug delivery to CNS?
Disrupt tight junctions, inhibit p-glycoprotein (efflux pump)
What virus increases the risk of head and neck cancer?
HPV 16 or 18
What are 2 signs of irreversible cellular injury?
Mitochondrial vacuolization and phospholipid-containing densities inside mitochondria.
What is the diagnosis? recommended treatment?
CMV retinitis; treat with ganciclovir
What urine osmolarity abnormalities can occur with lithium? carbamazepine?
Lithium - ADH resistance and nephrogenic DI (low urine osmolarity)
Carbamazepine - SIADH and high urine osmolarity (low serum sodium)
Describe the proression of paget disease of bone
originally osteolytic phase (osteoclast-dominated), then transitioning to an osteosclerotic phase (osteoblast-dominated).
What is the mechanism of action of sumatripan for migraine?
it is a serotonin agonist which stimulates trigeminal vascular receptors and reduces vasoactive neuropeptides (substance P and calcitonin gene-related peptide).
How does the coagulase test differentiate between staphylococci?
Coag +ve = Staph aureus
coag -ve = staph epidermidis, hemolyticus or saprophyticus.
What is the cause of these sskin lesions?
Erythema multiforme usually co-occuring with HSV or mycoplasma pneumoniae due to transmission of pathogen DNA fragments to keratinocytes and subsequent cytotoxic T-cell recognition of these fragments.
What type of brain hemorrhage are pre-term infants < 32wks gestation at higher risk?
Germinal matrix hemorrhage leading to bleeding into the lateral ventricles.
What is the route of infection and symptoms of Cryptococcus neoformans infection?
Pigeon dropping inhalation into lung.
Spherical yesat with thick capsules; india ink stain.
Initial infection is asymptomatic but can lead to meningitis in immunocompromised patients.
What changes to heart function occur in acute /massive PE?
RV obstruction and increase in pressure leads to hypokinesis (decr. O2 supply) and dilatation (stretch increases O2 demand), leading to RV infarct and failure
What additional PFT tests are useful for the diagnosis of asthma?
Bronchoprovocation with methacholine
Response to bronchodilators (e.g. levalbuterol).
What impact does CKD have on phosphate levels? what is the treatment & mechanism of action?
CKD impairs phosphate secretion in kidney leading to hyperphosphatemia.
Sevelamer binds oral phosphate and it is eliminated in feces.
Describe the compensatory mechanisms operating during asympomatic heart failure
Decreased CO triggers decrease in renal perfusion (RAAS stimulation) and lower baroreceptor stretch (sympathetic outflow, increased norepinephrine). Resulting vasoconstriction and salt/water retention increases preload and afterload.
What is the presentation of congenital hydrocephalus?
Macrocephaly with poor feeding progressive to developmental delay, spacticity and hyperreflexia (UMN signs).
Where in the lymph node does isotype switching occur?
In the germinal centres
What are the clinical manifestations and inheritance of the condition shown in the blood smear below?
hereditary spherocytosis: small RBCs with no central pallor.
Clinical manifestations: hemolytic anemia, jaundice and splenomegaly
AD inheritance.
What are the symptoms of major concern in theophylline intoxication?
Tachyarrythmias and seizures.
Which blood vessels are affected by nitrates?
large veins (via cGMP-mediated smooth muscle relaxation)
What are examples of true and false diverticula? What layers are present?
True diverticulum = 3 layers (mucosa, submucosa and muscularis) e.g. Meckel’s, appendix
False diverticulum = 2 layers (mucosa and submucosa only), zenker or diverticulosis.
How would you differentiate between CML and AML?
AML = 25%+ blasts
CML has myelocytes / metamyelocytes predominantly and low leukocyte ALP
What is the mechanism of action of anastrozole, letrozole and exemestane?
Aromatase inhibitors; stop conversion of testosterone into estradiol.
Gram positive rods with a narrow beta-hemolytic zone that can grow well in the cold…what are they?
Listeria monocytogenes
What are the common intracellular bacteria?
What immune response is required to get rid of these?
Obligate: Really Chilly and Cold (Rickettsia, Chlamydia and Coxiella)
Facultative: Some Nasty Bugs May Live FacultativeLY (Salmonella, Neisseria, Brucella, Mycobacterium, Listeria, Francisella, Legionella, Yersinia pestis)
Cell-mediated immunity
How would you differentiate between enterococcal endocarditis and viridans endocarditis?
Enterococcal typically eluderly men with cytoscopy or colonoscopy. No hemolysis, grows in bile & hypertonic saline
Viridans is associated with dental extraction and typically colonizes abnormal heart valves. Does not grow in hypertonic saline or on bile.
What are the causes of infectious mononucleosis? How do you distinguish between them?
Immunocompetent: EBV (heterophile +ve, sore throat, lymphadenopathy) or CMV (heterophile -ve, associated with transfusion of non-irradiated blood containing WBC).
Immunodeficient and heterophile negative: HHV-6, HIV, toxoplasmosis.
What is the classic triad of congenital toxoplasmosis?
chorioretinitis, hydrocephalus, diffuse intracranial calcifications
What are the symptoms and cause of age-related cataracts?
Gradual loss of visual acuity, excessive glare, halos, myopic, loss of red reflex.
Age-related oxidative injury or inability to metabolize sorbitol (diabetes)
What excretes brain natriuretic peptide
BNP is produced by the ventricles in response to increased wall stress.
What is the treatment for metatstatic prostate cancer or castration-resistant cancer?
17-alpha hydroxylase inhibitor (abiraterone)
What are the symptoms and treatment of drug-induced parkinsonism?
Rigidity, bradikinesia, tremor and masked facies
Decrease/discontinue drug or add anticholinergic (trihexyphenidyl or benztropine).
What is the pathogenesis of narcolepsy with cataplexy?
Low levels of hypocretin 1 (orexin-A) in CSF.
What is the mechanism of action of etoposide? Which cancers is it typically used for?
Inhibits topoisomerase II leading to double-strand breaks. Used for testicular and small cell lung carcinoma
Where are the common sites for obstructive hydrocephalus and what is the result?
Cerebral aqueduct (lateral + 3rd ventricle enlargement)
Foramen of monro (unilateral ventricular enlargement)
Foramen of Magendie, Foramen of Luschka (all 4 ventricles)
What vasoocclusive symptoms present early in patients with sickle cell disease? What serum abnormalities are expected?
dactylitis (hand/foot syndrome) with swelling, tenderness and erythema of the affected extremities
increased unconjugated bilirubin, LDH and haptoglobin
What differentiates exudative and transudative pleural effusion? What are common causes of each?
Light criteria: exudative if 1 of
plerual protein / serum protein > 0.5
plerual LDH / serum LDH > 0.6
or plerual LDH > 2/3 upper NL of serum
Typically infectious, malignant or rheumy
Otherwise transudative due to HF, cirrosis or nephrotic syndrome.
What colour does a reticulocyte stain under wright-giemsa? Why?
Blue due to residual rRNA
What is the diagnosis in a patient who wears gloves indoors and has fingers that turn blue when cold and has retrosternal burning and regurgitation when supine.
CREST syndrome:
She has features of Raynaud’s, esophageal dysmotility (reflux), and sclerodactyly (initial presentation is non-pitting edema progressive to thickened, tight, shiny skin).
Muscle fasciculation is most characteristic of what type of motor neuron lesion? What other signs accompany it? Where is the lesion?
Lower motor neuron;
Hypotonia, hyporeflexia or flaccid paralysis. Anterior horn or distal.
What is the histopathology of HIV dementia?
infected microglial cells cluster around necrotic areas (microglial nodules) and form multinucleated giant cells.
What are the complications of congenital CMV infection?
Chorioretinitis, sensorineural deafness, seizures, jaundice, hepatosplenomegaly and microcephaly
How do you estimate carrier frequency for a rare condition which affects 1 in x individuals?
Carrier frequency = 2sqrt(x)
What are the 3 pathogens that cause HIV associated-esophagitis?
Candida albicans, HSV-1 and CMV
How is CMV esophagitis diagnosed endoscopically? Microscopically?
Endoscopy shows linear ulcerations
Microscopy shows intranuclear and cytoplasmic inclusions
What is the difference beteen a hazard ratio and an odds ratio?
Hazard ratio is defined as the risk of an event in the treatment group vs the control group at a particular time t. Odds ratios are cumulative through the entire study
What is Loeffler syndrome? What is the cause?
Eosinophilic pneumonitis caused by migration of roundworms (Ascaris) through lungs.
What are the vascular regions most susceptible to atherosclerosis? Why?
Lower abdo aorta and coronary arteries due to turbulent flow.
What is the impact of hypovolemia on hematocrit, albumin and uric acid?
All increased; uric acid follows increased sodium resorption.
How does the weber lateralize in sensorineural and conductive hearning loss?
Conductive: lateralizes to affected ear (as decreased air conduction makes the vibrations easier to hear)
Sensorineural loss: lateralizes to unaffected ear.
What is the impact of von Willebrand disease on clotting tests?
Normal platelets, increased bleeding time, normal/increased aPTT (vWF is a factor VIII carrier protein), normal PT.
What injection location can cause a trendelenberg gait?
Superomedial buttock injection which injures the superior gluteal nerve.
What are the symptoms and cause of roseola?
3-5 days high fever followed by blanching macropapular rash that starts on the trunk and spreads outwards to face and extremities
commonly caused by HHV-6
What would cause adalimumab or infliximab efficacy to decline in a patient?
Development of an antidrug antibody.
What lung pathology is shown below? What substance drives the development of this lesion?
Granulomatous inflammation (note langerhans giant cell);
interferon-gamma
What sleep stage does sleepwalking occur in? What brainwaves are characteristic of this stage?
Non-REM stage 3;
Delta waves
What brain waves characterize the first 2 stages of sleep?
N1: theta
N2: sleep spindles & K complexes
What is hartnup disease?
AR metabolic disorder due to impaired transport of neutral AAs, esp. tryptophan.
Symptoms of niacin deficiency.
How do you calculate Vd?
How do different drug properties relate to the volume of distribution?
Vd = amount of drug given / plasma concentration of drug
Low Vd 3-5L suggests charged / large / tightly bound to plasma protein and remains in blood
Medium Vd 15-16 L means it’s small and hydrophilic and distributes into the interstitium
High Vd = intracellular or tissue preferential uptake (e.g. 40+L Vd).
What is the presentation of carnitine deficiency?
Low muscle carnitine, hypoketotic hypoglycemia due to inability to beta-oxidize FA, muscle weakness/cardiomyopathy.
What is the mechanism of action of desmopressin?
it is a synthetic analogue of vasopressin/ADH which causes vWF release from endotheleal cells.
How do you calculate positive predictive value?
Test positive / (test positive + false positive)
What are the symptoms of riboflavin (vitamin B2) deficiency? What enzymes are afffected?
Angular stomatitis, cheilitis, glossitis, seborrheic dermatitis, eye changes and anemia.
Succinate dehydrogenase (as riboflavin makes FAD)
What is the timing cutoff for symptoms which differentiates acute stress disorder from PTSD?
PTSD duration of symptoms is greater than 1 month
How do opiates provide analgesia?
Activation of the mu receptor blocks calcium influx and reduces excitatory release on the presynaptic membrane and increases potassium efflux on the postsynaptic membrane to induce hyperpolarization.
What causes the appearance of lamellar bodies and acid-fast staining of material accumulating in alveoli?
Pulmonary alveolar proteinosis (PAP) due to an imbalance between surfactant production and clearance, due to compromise of the alveolar macrophages.
What is the inheritance of neurofibromatosis type 1? Which chromosome is the gene located on?
single gene autosomal dominant; chromosome 17
What is the diagnosis of this tonsilar lesion? What is the most likely cause?
Keratin pearls, atypical mitotic figures -> head and neck mucosal squamous cell carcinoma. Caused by HPV exposure.
How would you distinguish between Cryptococcus and Candida?
Candida will grow true hyphae in serum at 37C “germ tubes”; Cryptococcus does not form hyphae.
how would you diagnose respiratory failure in the setting of DKA?
Higher than expected PaCO2 i.e. mixed metabolic + respiratory acidosis due to resp. fatigue and hypoventlation.
What is the cause of an S4?
Blood from atrial contraction hitting a stiff ventricle. Always pathologic in younger patients or if especially louder.
What is the change in renal venous pressure in the setting of CHF?
Renal venous pressure increases due to volume overload.
How does diptheria become toxigenic?
Infection with corynephage beta inserts the tox gene, resulting in production of diptheria AB toxin.
Describe the steps of base excision repair?
Glycosylase detects and removes uracil. Endonuclease cleaves 5’ and lyase cleaves 3’ sugar-phosphate.
Dna pol fills gap and ligase seals nick.
What is the histology of a cutaneous wart?
epidermal hyperplasia
hyperkeratosis
papilloma formation
and koilocytosis (cytoplamic vacuolization
What is the function of factor VIII?
Links factor IXa (protease) with factor X (substrate).
What are the symptoms of primary hyperaldosteronism?
Hypertension & hypokalemic alkalosis w muscle weakness and paraesthesias.
NO edema / or hypernatremia due to increased RBF/GFR and ANP.
What is the genetic cause of fragile X syndrome?
trinucleotide repeat expansion >200 causes hypermethylation of FMR1 leading to inactivation of gene.
What drugs improve survival in decompensated HF?
Beta blockers.
A fever, grayish exudate and partial soft palate paralysis would suggest what infection?
Diptheria!
Pneumobilia and small bowel obstruction suggests what condition?
Gallstone ileus.
When should you suspect SCID?
Lack of a thymic shadow, frequent infections, agammaglobulinemia (i.e. you have both B and T cell dysfunction).
Wha tis osler-weber-rendu syndrome? What is the inheritance?
Hereditary hemorrhagic telangiectasias of the skin and mucous membranes + severe nosebleeds.
AD
What is the mechanism by which physiologic stress leads to chnages in serum K+ levels?
High levels of catecholamines activate B2 receptor -> increased Na/K pump activity + Na/K/2Cl transporter activity
Net shift of K+ into cells results in hypokalemia.
What is the first-line treatment for glaucoma? What is their mechanism of action?
Prostaglandins eg. latanoprost.
Increases outflow of aqueous humor (decrease collagen in uveoscleretal outflow pathway)
What is the function of tazobactam?
It is a beta-lactamase inhibitor
What are the most comon organisms that cause acute otitis media?
Strep pneumoniae, H flu (nontypeable), Moraxella catarrhalis.
What medications can you use to address AFib? What are their mechanism of actions and side-effects?
Calcium channel blockers e.g. diltiazem and verapamil.
Slow sinus rate + conduction through AV node.
Complications include AV block, negative inotropic effect (don’t use if CHF), constipation (esp. verapamil).
What might you be concerned about if intubating a patient with long-standing RA?
vertebral subluxation of C-spine causing cord compression (absent reflexes, flaccid paralysis).
What are the acute and late tissue reactions of radiation?
Acute: erythema, desquamation, hair loss and sterility
Late: fibrosis (homogenization of collagen), necrosis, vascular bnormality.
Can also cause carcinogenesis/teratogenesis.
What vitamin deficiency is associated with measles complications?
Vitamin A is depleted by measles; suppleentation prevents karatitis and corneal ulceration and reduces comorbidities and recovery time
What is the best way to ensure that the correct operation is done on the correct body part & patient?
Dual independent verification by 2 different providers through the use of a surgical time out.
Where on the tRNA is the amino acid attached?
to the CCA-OH-3’ tail
When treating a migraine with metoclopramide or prochlorperazine, what drug do you want to also co-administer and why?
dopamine receptor blockers can cause extrapyramidal symptoms -> add dyphenhydramine for anticolinergic activity.
What is the ABGs expected when people travel to high altitudes?
persistent hypoxemia
respiratory alkalosis
metabolic alkalosis (compensatory - full normalization > 72 hrs)
What pathway for nitric oxide synthesis and vasodilation in endothelium?
Arginine + O2 is converted by endothelial nitric oxide syntase into NO -> diffusion to smth muscle
Smooth muscle guanlyate cyclase activated by NO produces cGMP == vasodilation
What is the location of a lesion with pure hemisensory loss?
contralateral ventral posterior lateral nucleus in the thalamus.
What does lipohyalniosis and microatheromas cause
lacunar infarcts within the basal ganglia, posterior limb of internal capsule, pons or cerebellum
Name the arteries indicated on this femorial angiogram
A) external iliac
B) inferior epigastric
C) common femoral
describe the differences between the pathophys of Salmonella enterica versus Salmonella typhi
S typhi produces capsular Vi antigen which suppresses neutrophil response, allows intracellular replication in macrophages and systemic spread -> typhoid fever (proressive fever, rose spots, abdo pain, hepatosplenomegaly, GI bleed)
Enterica = self-limited watery diarrhea. Enterica has animal vectors, typhi is only fecal-oral from other humans
What is the mechanism of action of ethosuximide?
Blocks thalamic T-type Ca2+ channels.
Describe characteristics reactive neutrophils.
Dohle bodies (cytoplasmic blue inclusions of RER), toxic granulations, cytoplasmic vacuoles.
Hypersegmented neutrophils (>6 lobes) are found in what diserase?
Vitamin B12 or folate deficiency (megaloblastic anemia).
What are the characteristics of buspirne? what is it used for?
Partial 5HT-1A agonistused for generalized anxiety disorder.
No risk of dependence, slow onset of action.
What happens when you take a fluoroquinolone with calcium carbonate or iron pills?
Insoluble compounts form resulting in impaired absorption
Where does collagen hydroxylation occur?
in the rough endoplasmic reticulum.
Which AA is a recursor to serotonin?
Tryptophan
Identify A-E
A) hippocampus
B) cerebellum
C) corpus callosum
D) pons
E ) thalamus
what do bats transmit?
rabies
What are the symptoms, key characteristsics and transmission of bubonic plague?
Symptoms: fever and swollen, painful, erythematous lymph nodes.
Yersinia pestis; gram-negative coccobacillus, reservoir is rodents, transmitted by flea bite.
Endemic to SW USA
What is this pattern of IF characteristic of in kidney?
glomerular basement membrane disease (e.g. Goodpasture)
What is somatomedin C?
IGF-1
What is the mechanism of hyperacute rejection of transplanted organs?
preformed recipient antibodies against graft antigens causing gross mottling and cyanosis & thrombotic occlusion.
Where are very long chain and branched-chain fatty acids metabolised? What syndromes occur when peroxisomes are defective?
Peroxisomes;
Zellweger syndrome: craniofacial abnormalities, hepatomegaly, profound neurological defects. Death within months.
X-linked adrenoleukodystrophy (defective tranport of VLCFAs into peroxisomes) presenting with neuro symptoms and adrenal insufficiency.
What are the causes and presentation of biotin (B7) deficiency?
What reactions are affected?
Cause acquired (raw egg whites due to avidin) and congenital.
Presentation: altered mental status, myalgias, anorexia, derm changes, metabolic acidosis (due to conversion of pyruvate > lactate).
Pyruvate carboxylase (gluconeogenesis), acetyl-CoA carboxylase and Propionyl-CoA carboxylase req biotin.
what happens to ABGs when gas exchange is diffusion limited?
Large alveolar - capilary gradient for O2 (normally would be the same approx 104 mmHg)
CO2 diffuses much faster than O2 therefore CO2 levels stay the same.
What is the treatment for recurrent calcium kidney stones?
Thiazide diuretic (reduces urinary Ca2+)
How does a patent ductus arteriosus initially affect CO, SVR, and atrial filling?
PDA shunts from systemic to pulmonary circulation, lowers SVR resulting in compensatory ncrease in CO.
As more blood enters pulmonary circulation, LA filling increases.
What is the presentation of trochlear nerve palsy?
Up and out eye; diplopia that is worse when looking down and nasal e.g. when walking down stairs or reading up close.
Identify A-E
A - descending aorta
B - esophagus
C - trachea
D - aygos vein
E - pulmonary artery
What is bacillary angiomatosis?
Red-purple papular skin and/or visceral lesions caused by Bartonella henselae infection in immunocompromised pt
What is the cause of the acid-fast stain seen on this liver slide?
a1-antitrypsin deficiency; granules composed of unsecreted AAT polymers which cannot be digested.
Describe the 3 mechanisms of action and examples of direct-acting antiviral therapy for HCV infection
Sofosbuvir - RNA-dependent RNA polymerase inhibitor
Simeprevir - HCV protease inhibitor
Ledipasvir - NS5A inhibitor (prevents viral replication and assembly)
What would you use to manage bradycardia + hypotension associated with inferior wall MI?
Atropine - blocks vagal tone which contributes to bradycardia
Describe the morphology of the mature HepB virion
enveloped, partially double-stranded circular DNA in a hexagonal capsid.
Which antibiotic can precipitate serotonin syndrome? What infections is it commonly used for?
Linezolid due to MAOI activity.
MRSA and VRE
What are some examples, mechanism of action and side effects of stimulant laxatives?
Bisacodyl and senna
Stimulates peristalsis
Causes cramping, electrolyte disturbances.
What type of laxative is docusate?
A surfactant laxative (stool softener).
What is the cause and presentation of osmotic demyelination syndrome?
Cause is too-quick correction of chronic hyponatremia causing apoptosis and demyelintaion of the pons.
Pseudobulbar palsy, quadriparesis, horizontal gaze paralysis, obtundation or “locked-in” syndrome.
In what order do you give antidoes for organophasphate toxicity?
Atropine first (block muscarinic receptors), then pralidoxime due to the latter’s transient AchE inhibition.
What is reverse T3?
Inactive T3 generated from peripheral conversion of T4
What happens to extracellular potassium concentrations in DKA? Why?
Increased due to loss of free water via increased plasma osm and due to lack of insulin to shift K+ into cells.
Describe the imaging
Bilateral ground glass opacification and air bronchograms; atelectasis.
Describe how ventilation and perfusion change in the lung when standing?
Ventilation is highest at the apex and lowest in the base
Perfusion is highest in the base and lowest in the apex (due to gravity).
What is the difference between projection and displacement?
Projection is attributing your own feelings to others.
Displacement is transferring your feelings to a less threatening object or person
What is the presentation of tyrosinase deficiency?
Albinism due to inability of melanocytes to to synthesize melanin.
What is the enzyme responsible for classic PKU? What if there is also a dopamine deficiency?
Classic PKU: deficiency of phenylalanine hydroxylase.
PKU + downstream deficiencies of neurotransmitters is caused by dihydrobiopterin reductase, which makes the cofactor needed for phenylalanyne hydroxylase and tyrosine hydroxylase (both are req’d to make DOPA).
Which muscles insert on the lateral epicondyle of the humerus? what is the presentation of tendinitis at this location?
Extensor carpi radialis previs & extensor digitorum.
Weakness or pian with wrist extension = tennis elbow.
What are the origins and insertions of the 3 major hip flexors?
Iliopsoas (T12-L4 & iliac fossa -> lesser trochanter of femur)
Rectus femoris (AIIS -> base of patella (quad tendon))
Sartorius (ASIS -> pes anserine)
How does damage to the intervertebral disc present?
What causes anterior displacement of the vertebral body?
Disc damage -> herniation, loss of space between vertebrae.
Bilateral pars interarticularis fractures -> spondylolisthesis
What is the difference between primary infection and reactivation of HSV-1
Primary herpetic gingivostomatitis; multinucleated cells on Tzanck smear, more severe.
Reactivation generally mild perioral vesicles.
What are the most common infectious bacteria that are associated with septic abortion?
Staph aureus, E coli or other gram-neg bacilli, GBS
How does mitral stenosis affect LV end-diastolic pressure? What change in LVEDP suggests aortic valve disease?
Mitral stenosis LVEDP is normal or low due to reduced outflow from LA. If LVEDP is increased, think aortic valve pathology (i.e. stenosis)
What is the mechanism of action by which trinucleotide repeats in huntingtin gene cause disaese?
CAG repeat -> polyglutamine expansion -> GoF mutation in huntingtin -> histone deacetylation -> transcriptional silencing.
What medication is lowest-risk pharmacological intervention for insomnia in the elderly?
Ramelteon (binds melatonin receptors in superchiamatic nuc)
What is the mechanism of action of the combined OCP?
Suppression of GnRH -> lowers FSH/LH and prevents ovulation.
What is the presentation of PSGN on IF and EM?
IF - granular staining of C3 along GBM
EM - Subepithelial humps .
“Lumpy bumpy”
What is the function of JAK2 (mutated in polycythemia vera)?
JAK = Janus Kinase 2, a non-receptor, cytoplasmic tyrosine kinase which mutations result in constitutive activation (i.e. in the absence of erythropoetin).
What is the most common cause of hypoketotic hypoglycemia?
Deficiency of acyl-coA dehydrogenase.
What are the adverse effects of steroid use?
Skin MSK: Central obesity, buffalo hump, skin atrophy and proximal muscle weakness
GI: peptic ulcer or GI bleed due to suppression of prostaglandins
Endocrine: HPA suppression, hyperglycemia, hypogonadism, osteoporosis
Immune: Neutrophilia due to demargination, immunosuppression
Nervous: Hypomania or psychosis, sheep disturbance
Resp: Increased surfactant production.
What is the typical presentation of HUS?
often follows EHEC infection; bloody diarrhea
triad: hemolytic anemia + schistocytes, thrombocytopenia, AKI.
What is the primary animal reservoir of EHEC?
Cattle GI tract
What is the superficial lymphatic drainage from the lower limb?
Medial to superficial inguinal nodes
Lateral to popliteal nodes and then to deep inguinal nodes.
what types of hallucinations occur in schizophrenia?
Most commonly aural - tactile or olfactory more likely to be due to concomittant substnace use.
What are the criteria for the diagnosis of schizophrenia? Can you have positive and negative symptoms at the same time?
>=6months of continuous impairment with functional decline
2 or more of: delusions, hallucinations, disorganized speech, disorganized or catatonic behaviour or negative symptoms (apathy & flat affect).
What are the etiologies of syncope?
Vasovagal (think trigger, prodrome)
carotid hypersensitivity (drop in SVR due to tactile stimulation of carotid sinus)
autonomic dysfunction (orthostasis, existing disease)
hypovolemia (volume loss, orthostasis)
LV outflow obstruction (assoc. with exertion, systolic murmor)
VTach (no warning symptoms, cardiomyopathy, ischemic heart disease, long QT)
Conduction impairment (fatigue, lightheadeness, ECG abnormality)
Which nerve can be compressed by parotid gland tumors? What is the presentation?
The facial nerve (CN VII) which provides motor innervation to the muscles of facial innervation. Non forehead-sparing facial droop.
What are the rapid-acting insulin analogs?
Lispro, aspart or glulisine
What are the long-acting and intermediate-acting insulin analogs?
Long-acting: Glargine, detemir, degludec
Intermediate: NPH (twice daily)
Name the 5 hypothalamic nuclei which have “homestatic” functions
Ventromedial (satiety) and Lateral (hunger)
Anterior (heat dissipation) and Posteerior (hypotherma)
Suprachiasmatic: circadian rhythm, pineal gland
Name the 5 hypothalamic nuclei that secrete hormones
Arcuate: dopamine, GHRH
Medial preoptic: GnRH, sex
Paraventricular: oxytocin, CRH, TRH
Supraoptic: ADH
What is the mechanism of transmission of Campylobacter jejuni
contaminated food (e.g. undercooked poultry) and domesticated animals (esp puppies!)
What types of food are associated with Vibrio parahaemolyticus gastroenteritis? What individuals are more prone to developing sepsis?
Contaminated seafood e.g. shelfish. Can cause sepsis in people with liver disease or hemochromoatosis.
Does insulin contribute to the disease process of T2DM?
No, it is elevated as a result of insulin resistance associated with obesity or high levels of FA
What proteins are bound by von Willebrand factor?
platelet Gp1b to exposed collagen under damaged endothelium
and factor VIII (as a carrier, preventing proteolytic degradation)
What are the 3 types of prostatic hyperplasia? Which one responds best to finasteride? Alpha blockers?
Epithelial predominant - finasteride
Smooth-muscle predominant - alpha blocker
Collagen-predominant
What is the innervation, origin and insertion of latissimus dorsi? What are the primary movements?
Innervation: thoracodorsal nerve
Origin: iliac crest and lumbar fascia to spinous processes of T7-12 and lower ribs
Insertion: bicipital groove of humerus
Primary functions: extension, adduction and medial rotation of humerus
What type of cardiac cell makes this tracing? What phase of the action potential is affected by class IV antiarrhythmic drugs?
slow-response tissues (pacemaker cells) of SA and AV nodes.
phase 0 (upstroke) is slowed by verapamil / diltiazem due to their effect on L-type calcium channels.
What are the characteristics of edwards syndrome (trisomy 18)?
Dysmorphic features: micrognathia, low-set ears, prominent occiput, rocker bottom feet
Hyertonia, e.g. clenched hands, overlapping fingers.
Heart, GU, GI abnormalities
IUGR
What is the function of dystrophin?
links actin to the cytoskeleton, stabilizes the sarcomere. Loss of dystrophin leads to myonecrosis.
mutated in DMD / BMD
What is medical therapy for symptomatic gallstones?
Ursodeoxycholic acid (hydrophilic bile acids)
Improves cholesterol solubility & helps dissolve gallstones
What is the impact of chronic alcoholism on TCA?
Thiamine deficiency, blocks pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase complex.
NAD+ depletion; all steps which consume NAD+ are inhibited
Why do patients with CF have dehydrated mucus, yet have salty sweat?
CFTR inhibition means loss of chloride leaving the cell (i.e. inside is more -ve), which means that there is more sodium flux via ENaC. Increased sodium flux pulls water into the cell.
CFTR is reversed in sweat glands, normally absorbing luminal chloride and pulling sodium and water out of the sweat.
How do you calculate cumulative incidence?
Number of cases that develop over a given time period / number of susceptible people in the population at the beginning of the period.
How can a venous embolus bypass the lungs and end up causing a stroke?
Patent foramen ovale (PFO); present in 25% of adults, but functionally closed due to LA > RA pressure. Valsalva release can transiently open the PFO.
What is the most common complication of adult rubella?
polyarthritis / polyarthralgias
What are the 3 biologic suffixes?
- mab/pab is a monclononal antibody
- nib is a tyrosine kinase inhibitior
- cept is a receptor molecule
What is the mechanism of action of etanercept?
It is a decoy receptor for TNF-alpha
what is the innominate artery?
the (right) brachiocephalic artery.
What is subclavian steal syndrome?
When either subclavian artery is occluded, bloodflow in the ipsilateral vertebral artery is reversed and “steals” from the contralateral artery, diverting blood away from the brainstem.
Symptoms include arm ischemia and vertebrobasilar insufficiency (dizziness, vertigo etc.)
identify the pathogen in this lung biopsy. What are the key characteristics?
coccidioides immitis
mold in the cold.
thick-walled sperules with and w/o endospores.
Culture on sabouraud agar.
Testicular swelling and tenderness localized to the posterior and superior areas is suggestive of what diagnosis?
Epididymitis; typically caused by Chlamydia or Gonorrhea in younger men or colonic flora in older men.
What is the cause of kidney disease in multiple myeloma?
Free light chains from Ig enter through glomerulus and form obstructive casts causing kidney injury.
What leads to rebound “rhinorrhea”? how do you manage it?
use of topical decongestants >3 days. Stop decongestents to restore normal norepinephrine production.
How do you treat primary hypergonadism?
replace estrogen or testosterone.
What is the cause of splenomegaly in the setting of hemolysis?
Red pulp hyperplasia
What drugs cause a use-dependent prolongation of the QRS complex without QTc prolongation?
Class 1C antiarrhythmics: Flecainide, propafenone
How do you differentiate between bulimia nervosa, binge-eating disorder and body-dysmorphic disorder?
Bulimia: binge eating +compensatory behaviour to prevent weight gain and excessive worrying about body shape and weight
Binge-eating disorder is bulemia without compensatory behaviours
Body-dismorphic disorder: intense preoccupation with a perceived defect in physical appearnce, significant functional impairment, does not meet criteria for eating disorder.
Identify the lesion. What is the presentation of the nerve most likely affected?
This is a retroperitoneal hematoma, common in patients that are anticoagulated.
Femoral nerve compression can occur (note the psoas muscle is squished) leading to quadriceps weakness, decreased patellar reflexes and sensory loss over anteromedial thigh.
What inherited cause explains a loud S2 and right axis deviation on ECG? What is the causative mutation and inheritance pattern?
pulmonary arterial hypertension due to inactivating mutation in BMPR2; AD with variable penetrance.
Which cells express MHC II? How does it work?
Antigen presenting cells phagocytose extracellular pathogen in lysosomes (acidic) and then fused onto an MHC class II molecule which is sent to the cell surface for presentation to a CD4+ T cell.
Where is the AV node located?
on the endocardial surface of the RA, near the coronary sinus and the septal leaflet of the tricuspid valve.
How does diastolic pressure, afterload and contractility change in mitral valve stenosis?
Intially, all 3 are normal. Contractility may increase in advanced disease due to decreases in diastolic pressure and afterload (due to decreased filling).
What is the presentation of acute or chronic arsenic poisoning? What is the treatment?
Acute: garlic breath, vomiting, diarrhea and QTc prolongation
Chronic:skin changes (pigmentation, keratosis), stocking-glove neuropathy.
Treatment: dimercaprol
What are the non-enveloped RNA viruses?
Reoviruses, Picornaviruses (PERCH), hepevirus (HEV), calicivirus (norovirus)
What is a glomangioma? What is the characteristic appearance?
A benign tumor originating from smooth muscle cells that control thermoegulation via glomus bodies. Characteristic appearance is a red/blue small lesion under a nail bed.
Which drug interactions can cause a methadone overdose?
Inhibitors of CYP3A4: azoles, fluvoxamine, ciprofloxacin, clarithromycin and cimetidine.
What is first-line therapy for essential tremor?
Non-selective beta blocker (e.g. propranolol)
What tuberculosis drug produces red-orange body fluids? What is its mechanism of action?
Rifampin; inhibits bacterial DNA-dependent RNA pol
chronic, treatment-refractory rhinosinusitis with nasal polyps and failure to thrive is most likely…
CF
What is itchthysosis vulgaris?
inherited disorder with mutation of the filaggrin gene leading to defective desquamation and dry, scaly skin with loss of barrier function. Extensor surfaces most commonly affected with flexural sparing.
What is the most likely diagnosis? What would you see on histology?
Mesothelioma
On histology: either epithelial-like or spindle cells with staining for cytokeratins and calretinin.
What is the diagnosis? What are the key characteristics?
Lichen planus: 5Ps it is pruritic, purple or pink, polygonal, papules & plaques.
Wickam striae; Kôbner phenomenon
Found on skin, oral mucosa, and genitalia
What is the major toxicity of trastuzumab?
reversible cardiotoxicity associated with decreased contractility without destruction or fibrosis.
Describe the biochemistry of alkaptonuria.
Lack of homogentisic acid dioxygenase blocks conversion of tyrosine to furmarate; accumulation of homogentisic acid which turns black when oxidized.
What causes the electrolyte abnormalities seen in thiazide diuretics?
volume depletion causes activation of RAAS, increases urinary excretion of K+ and H+ (so serum hypokalemia and metabolic alkalosis)
Identify the substances 1-5 in the graph of proximal tubule concentrations.
- creatinine
- urea
- Na+, K+
- HCO3-
- Glucose and AAs
This chronic alcoholic has oculomotor dysfunction, ataxia and encephalopathy (cofusion and anterograde amnesia). What is the diagnosis and what structure on the diagram is most affected?
Wernicke encephalopathy due to thiamine deficiency; mamillary body (B) will demonstrate atrophy or hemorrhage.
Describe the immune response in leprosy.
Initial tuberculoid leprosy characterized by TH1 response ( IL-2, IFN-gamma, IL-12), +ve lepromin skin test.
Lepromatous leprosy characterized by humoral immnity (TH2: IL-4, IL-5 and IL-10) response and a negative lepromin skin test.
What is the pathogenesis of COPD?
- alveolar macrophages are activated due to irritants
- Macrophages recruit neutrophils; which produce neutrophil elastase and MMP9
- Macrophages secrete cytokies to recruit CD8+ T cells which destroy alveoli.
What are the electrolyte changes in tumor lysis syndrome?
Hyperphosphatemia, hyperuricemia, hyperkalemia and elevated LDH
What is the drainage from internal hemorrhoids? External hemorrhoids?
Internal: superior rectal vein -> inferior mesenteric vein
external: inferior rectal veins -> internal pudendal
What is the first sign of uncal herniation?
ipsilateral oculomotor nerve palsy starting with a fixed+dilated pupil.
What is the difference between somatic mosaicism and germline mosaicism
Germline mosaicism affects offspring, but not parent. Heritable.
Somatic mosaicism affects body cells manifesting disease.
Sometimes you get both.
What is the diagnosis? What is the presentation?
Hairy cell leukemia
Infiltration of the bone marrow causes fibrosis and failure -> pancytopenia.
Infiltration of red pulp -> massive splenomegaly, LUQ pain, fatigue ,weakness, fever and recurrent infections.
Label A-F
A - ischiocavernosus
B - bulbospongiosus
C - perineal body
D - levator ani
E - external anal sphincter
F - anococcygeal body
In what stage of sleep do nightmares occur? What about sleep terrors?
Nightmares - REM sleep.
Night terrors occur during slow-wave sleep
Label A-G
A - trapezium
B - capitate
C - scaphoid
D - lunate
E - pisiform
F - trapezoid
G - hamate
What is the most frequently injured abdominal organ in MVAs? What does it predispose individuals to?
The spleen; asplenia predispose to sepsis from encapsulated bacteria e.g. Strep pneumo, H flu, N meningitidis.
Name the bug. What is the treatment?
Aspergillus fumigatus;
V shaped, narrow septated hyphae.
Treatment is amphotericin B
This person presents with proximal muscle weakness. What is the diagnosis? What conditions are associated with it?
Diagnosis: dermatomyositis (perifascicular inflammation), muscle shows grotton papules over bony prominences.
May occur due to paraneoplastic syndrome of adenocarcinoma (ovary, lung, pancreas).
Differentiate between the two types of heparin-induced thrombocytopenia.
Type 1: non-immun-mediated caused by platelet clumping, generally milder course with thrombocytopenia >100,000-/mm3. Typically occurs <2 days post-heparin.
Type 2: heparin causes conformational change in platelet factor 4, which creates an antigen. IgG antibodies form, causing agglutination. Typically occurs >5 days post-heparin.
What would you see in active MS on histology?
Focal demyelination with plaques with perivenular inflammatory infiltrates (largely T-cells and macrophages).
What are the 3 openings through which each division of CN V passes through?
Superior orbital fissure - V1 opthalmic
Foramen rotundum - V2 maxillary
Foramen ovale - V3 mandibular
Acute recurrent flank pain and hydroureter; what is your #1 differential? What would you see on urinalysis?
Ureterolithiasis.
Free RBCs on urinalysis (RBC casts = glomerular bleeding).
What is diphenoxylate used for? what is the mechanism of action?
Anti-diarrheal agent, binds opioid mu-receptors in gut and slows motility.
What drug is the blue line?
Lidocaine or mexiletine (class 1B antiarrhythmic, weaker Na+ channel binding)
What are the contraindications of testoosterone replacement therapy and potential adverse effects?
Contraindicated if prostate cancer, hematocrit > 50% or severe OSA
Adverse effects include erythrocytosis and VTE.
What cardiac pathology occurs in acromegaly?
LV hypertrophy due to stimulation of GH.
What is the diagnosis in this child with nephrotic syndrome? What will you find on EM?
Minimal change disease (normal LM glomeruli, no immune deposits)
EM effacement of podocyte processes.
What is the difference between familial chylomicronemia and familial hypercholesterolemia?
Familial chylomicronemia due to defect in lipoprotein lipase or ApoC-II: presentation is elevated chylomicrons (hypertriglyceridemia), acute pancreatitis, lipemia retinalis and eruptive xanthomas.
Familial hypercholesterolemia due to defect in LDL receptor or ApoB-100 presentation is elevated LDL, premature heart disease, corneal arcus, tendon xanthomas and xanthelasmas.
Why would someone with STEMI present with eye pain?
If they are treated with atropine for bradycardia, it will cause mydriasis and blockade of aqueous humor outlflow, leading to glaucoma.
What is the cause of high-altitude pulmonary edema?
Hypoxic vasoconstiction -> increased pulmonary pressure -> patchy edema, bilateral crackles.
What is associated with abacavir hypersensitivity reaction?
HLA-B*57-01
Abacavir binds it, causing self-peptide presentation and cytotox T-cell response.
Delayed rash, fever, malaise, GI symptoms
What lesion would produce a medial rectus palsy?
Ipsilateral medial longitudinal fasciculus lesion.
What is the sensory distribution of the tibial nerve?
plantar surface of the foot.
What brain pathology is associated with autosomal dominant polycystic kidney disease (ADPKD)? What is the presentation?
Berry aneurysms of the circle of Willis -> subarachnoid hemorrhage
“Worst headache of my life”
What is the difference between tenofovir-induced nephrotoxcitiy and TMP-SMX nephrotoxicity?
Tenofovir: interferes with mitochondrial DNA + cellular damage in the proximal tubule (phosphaturia, glucosuria, proteinuria) with loss of brush border, giant mitochondria (eosinophilic inclusions)
TMP-SMX (used in advanced AIDS): interstitial nephritis and AKI, not focal cellular damage to prox tubule.
What virulence factor leads to necrotizing pneumonia from Staph aureus?
Panton-Valentine leukocidin (PVL), acquired by bacteriophage. Causes tissue necrosis and destroys leukocytes.
What is this finding? What procedure was recently performed on this individual? What other symptoms might they present with?
Livedo reticularis
Microangiopathy due to cholesterol emboli dislodged by invasive vascular procedures esp if atherosclerosis.
Can also present with blue toe syndrome, bowel ischeimia, stroke or renal infrct.
Which immune cells are associated with sarcoidosis? What cytokines are important in the progression of disease?
CD4+ T-cells and macrophages.
interferon-gamma and TNF-alpha
What substance causes hepatic encephalopathy?
Ammonia (NH4+) in blood
NOT urea.
What are the adverse effects of PDE-5 inhibitors?
Hypotension
Blue discoloration of vision, sudden monocular vision loss (due to PDE6 inhibition in retina)
Priapism
Flushing, headache, hearing loss.
Activation of which receptors would produce this pattern of changes?
Alpha 1 adrenergic receptors
What organism can cause a flu-like illness with bilateral conjunctival suffusion that is culture negative on routine media? What is the source of exposure?
Leptospira (spirochete)
Water contaminated by animal urine
How would you differentiate hypersensitivity pneumonitis from idiopathic pulmonary fibrosis?
Both present with a restrictive pattern, BUT idiopathic fibrosis does not have biopsy findings (granulomas) and typically presents much older >50yo.
Why do peripheral neurons regenerate when CNS neurons cannot?
After transection in PNS, schwan cells degrade myelin and recruit macrophaqges to clear debris & secrete trophic factors.
In CNS the oligodendrocytes undergo apoptosis and microglia are slow to remove myelin debris, which suppress neuron growth. Astrocyte proliferation leads to a glial scar, further blocking regenreation of the neuron.
What enzyme changes in stool is diagnostic for pancreatic insufficiency
Decreased elastase levels in stool.
What is the first-line pharmacotherapy for patients with sarcoidosis?
Glucocorticoids
very high ALP with insidious onset severe pruritis in the setting of autoimmune disease is suggestive of…
Primary biliary cholangitis
What is this cell? What are the key features? What is the pathogenesis?
Koilocyte: immuature squamous cell, perinuclear halo, “raisin nucleus”
HPV infection
What is the treatment for genital HSV infection? Does treating the initial infection result in less recurrance?
Oral daily valacyclovir, acyclovir, or famciclovir
No; treating the first infection does not alter recurrance rates.
In tranesophageal echo, when the probe is facing forward, which chamber is it closest to?
The left atrium
What ABGs are expected in the 3rd trimester of pregnancy?
Hyperventilation due to progesterone -> subjective SOB -> respiratory drive.
Respiratory alkalosis with metabolic compensation
What are the genital lesions present in each stage of syphilis?
- painless chancre
- condyloma lata
- gummas (necrotizing granulomas that are white-gray rubbery lesion).
What fungal infections are caspofungin and TMP-SMX used for?
Caspofungin - aspergillosis
TMP-SMX - pneumocystis
Describe the steps in the pathogenesis of cholecystitis
Persistent gallstone obstuction (biliary colic) -> disruption of mucus layer -> chemical irritation, inflammation of mucosa & deep tissues -> hypermotility with increase in internal pressure -> ischemia -> bacterial invasion of necrotic wall.
What condition would cause subcutaneous crepitus on lung exam?
Pneumothorax (esp. traumatic)
What changes in absorption of nutrients are expected in a patient on PPIs?
Malabsorption of calcium, iron, magnesium & B12
Lower acidity improves fat absorption for pts on pancreatic enzyme replacement by preventing lipase degradation in the stomach.
Why does retching and vomiting cause mallory-weiss tears? What is a strong associated predisposing factor?
Increased intraabdominal pressure; hiatal hernia.
What is the difference between dofetilide and dobutamine? What are their adverse effects?
Dofetilide is a class III antiarrhythmic which slows repolarization by blocking potassium channels. Leads to prolongation of QT and increased risk of polymorphic ventricular tachycardia
Dobutamine is a beta-1 agonist used for congestive heart failure; can cause HTN, angina, arrhythmia and tachycardia
What does immunoreactivity of synaptophysin indicate?
Neuronal origin of tumor (or neurectoderm or neuroendocrine).
Which tumors stain with GFAP?
Gliomas (astrocytomas, oligodendrogliomas and ependymomas).
What is the presentation of contrast-induced nephropathy?
Acute rise in creatinine and BUN subsequent to contrast administration, ATN with muddy brown casts on UA
What are the key pharmacokinetic differences in the neonate vs the adult?
Neonates have:
higher % body water & an immature BBB
Lower CYP activity and glucuronidation
Lower renal blood flow and GFR
Lower plasma protein levels
What is the structure in the rectangle? What CN exits at this level?
The middle cerebellar pedicle (pons) -> CN V trigeminal nerve
What does the t(15;17) translocation responsible for acute promyelocytic leukemia code for? What is used for treatment of APML?
PML-RARA, an abnormal retinoic acid receptor which inhibits differentiation.
Use all-trans retinoic acid for treatment.
What ligaments attach to the stomach? What is their composition
Lesser omentum (hepatogastric & hepatoduodenal ligaments, double fold of peritoneum)
Greater omentum (visceral peritoneum)
What the gram-positive rods in blood cultures?
Corynebacterium
Listeria
Actinomyces
Nocardia or
Clostridium
What are the virulence factors that are unique to Listeria monocytogenes?
Listerolysin O: makes pores in phagosome membranes to allow bacteria to escape
Actin-based transcellular spread
what characterizes a the fluid in a pericardial effusion in the context of malignancy?
Often hemorrhagic fluid with atypical malignant cells.
Subacute accumulation over weeks until volumes exceed stretch capacity, causing cardiovascular dysfunction.
What is this malformation? How does it present in infancy?
Dandy-walker malformation
Hypoplasia of cerebellar vermis, and dilatiation of 4th ventricle with posterior fosa enlargement.
Presents with head enlargement and developmental delay
What is this malformation? What is the presentation?
Chiari malformation
can cause syringomyelia and headaches or movement problems but can also be asymptomatic.
What is the pathophysiology of a ganglion cyst?
Mucoid degeneration of periarticular tissue which collects fluid via 1-way valve.
Identify A-E (this is a section at L2). What direction are you facing when you look at the CT?
A - descending duodenum
B - IVC
C - abdo aorta
D - duodenum (4th part)
E - L renal vein
Looking up from the patient’s feed towards their head.
What is the diagnosis? What are the key characteristics?
Cryptosporidium parvum
Blunting of brush border, cystic appearing acid-fast organisms on the brush border.
A patient presents with arthralgias, fatigue low-grade fever and weight loss, SOB and cough. CT below. What is the diagnosis? What would you see on biopsy? What marker is associated?
Granulomatosis with polyangiitis (note cavitary lesion on CT)
necrotizing vasculitis with granuliomas, no immunoglobulin or complement deposition.
PR3-ANCA / c-ANCA
What is the pathology? What caused it?
Subdural hematoma
Rupture of the bridging veins
What is the diagnosis of this lung specimen? What does this pathology predispose this patient to?
Bronchiectasis (note thick, widened airways with mucous plugging)
Bronchial artery hemorrhage
What organism is responsible for this presentation? What would you see on a KOH slide?
Tinea versicolor, caused by Malassezia yeasts.
Spaghetti and meatball appearance under LM/KOH
What is the diagnosis? How would this present? What is the causative organism?
Scabies
Intense pruritis which begins on the hands, flexor surfaces of wrist, lateral fingers and finger webs and can spread up to the elbow and axilla, which is worse at night.
Sarcoptes scabiei mite
Label A-E
A - Bladder
B - prostatic urethra
C - membranous urethra
D - bulbous urethra
E - penile urethra
What class of antiarrhythmic drugs would produce the following ion changes?
Class III antiarrhythmic (amiodarone, sotalol, dofetilide). Blockage of potassium channels slows repolarization and prolongs the AP.
Label the gastric histology
A - simple columnar epithelial cells
B - upper glandular layer (incll clear parietal cells)
C - deeper gastric glands (delta and chief cells)
D - Muscularis mucosae
E - Submucosa
What is this? What exogenous stimulus can cause it to form?
Granuloma; can form in response to a foreign body (cannot be digested by macrophages).
What is the diagnosis?
Metastatic liver disease (note multiple nodules)
hcc is much less common than mets
What is the diagnosis? What does the fluid contain? What are the walls made up of?
Pancreatic pseudocyst containing pancreatic enzymes. Walls are made up of granulation tissue and fibrosis occurs over time.
What 2 conditions could produce this presentation?
G6PD defienciency and glutathione reductase deficiency.
What is this tissue? What factor is responsible for producing it?
Granulation tissue; VEGF release.
What valve pathology corresponds to this tracing? Where will the sound be loudest? What’s different compared to a normal tracing?
Aortic regurg; C (i.e. shortly following closure of the valve)
Note loss of dicrotic notch at closure of the aortic valve and steep diastolic decline in aorta pressure.
Label A-E binding sites
A/B: Antigen binding site
C: Disulfide bonds
D: C1 attachment site
E: Fc receptor binding site
What is this cell? What do the granules contain? What infections trigger it?
reactive lymphocyte
Granules contain perforin and granzymes to punch holes and trigger cell death of infected cells
Infectious mononucleosis (EBV)
What tests are used to distinguish streptococci?
This patient presents with cough and weight loss? What is the diagnosis?
Active TB (note cavitary lesion)
What infection presents with flask-shaped ulcers (see below) on intestinal biopsy?
Entamoeba histolytica
Identify the organism. What are the key characteristics and typical presentation?
Mucor, Rhizopus or Absidia: nonseptate hyphae branching at 90 degree angles
Affects paranasal sinuses of people with DKA or underlying immunosuppression
What microscopic findings would you see on skin biopsy of these lesions?
Henoch Schonlein purpura
IgA and C3 deposition on IF
On LM damaged small vessels with fibrinoid necrosis, perivascular neutrophilic inflammation
What is the diagnosis?
Lichen planus
What is the diagnosis? What is the culprit? Where does the infection occur?
Tinea corporis
Dermatophytes - trichophyton rubrum is most common
Infects the superficial epidermis (stratum corneum) no deeper invasion
What is the diagnosis? What is the stain positive for?
Myeloblasts with auer rods: APL
Myeloperoxidase stain
What predisposes individuals to this esophageal pathology?
Barrett’s esophagus and esophageal adenocarcinoma:
Chronic GERD, Obesity, smoking, meds that lower eso tone (nitroglycerin) and nitroso foods (deli meat).
What is the diagnosis in this immunocompromised patient? What is the most common causative organism?
Ecthyma gangrosum, caused Pseudomonas aeruginosa
What is the diagnosis based on the imaging? How would you differentiate this presentation from a large pleural effusion?
Right mainstem bronchus obstruction - trachea deviates towards affected side
Large PE or hemothorax -> trachea deviates away from affected side.
What is the pathology present in this slide? Key features?
Carcinoid tumor - uniform size and shape of neuroendocrine cells forming islands with eosinophilic cytoplasm and round/oval strippled nuclei.
Most often benign, found at the tip of the appendix, but can produce liver mets -> carcinoid syndrome
What is the cause of these lesions in this patient that presents with a Virchow node and B symptoms?
Seborrheic keratoses (rapid-onset) due to GI malignancy e.g. gastric adenocarcinoma
What is the cause of this testicular pathology?
Testicular torsion, often associated with inadequate fixation of the lower pole of testis to tunica vaginalis
Describe the primary ion flows for each letter on the cardiomyocyte action potential curve
A- nothing
B- Na+ IN
C - K+ OUT
D - K+ OUT and CA++ IN balanced
E - K+ OUT
What is the diagnosis based on this kidney slide?
Hypertensive nephrosclerosis - note “onion-skin” appearance
What is the lesion?
Molluscum contagiosum (note intracytoplasmic eosinophilic inclusion bodies)
Gout or pseudogout? What are the crystals made of?
Rhomboid positively birefringent crystals of calcium pyrophosphate
pseudogout
What is the pathology on this lung biopsy?
Adenocarcinoma - frequently affects nonsmokers
What pathology is shown on this lung biopsy? What is the
Actinomycosis due to actinomyces infection after aspiration.
Characteristic sulfur granules will appear purple on H&E
Name A-E
What are the two black spots?
A - SVC
B - Ascending aorta
C - pulmonary trunk
D - esophagus
E - descending aorta
Black spots = mainstem bronchi
This individual presents with acalculus cholecystitis. What is the diagnosis based on this biopsy of the submucosal gallbladder vessels?
Polyarteritis nodosa
Note fibrinoid necrosis of arterial wall + luminal narrowing and thrombosis
What is the diagnosis?
What are some causes?
Constrictive pericarditis
note thickening and calcification of the pericardium.
Radiation, cardiac surgery, TB
What is the diagnosis? What is the cause?
Cirrhosis of the liver due to replacement of the normal lobar architecture by regenerative parenchymal nodules.
What is the diagnosis? How would the lesion appear grossly?
Leukocytoclastic (small-vessel) vasculitis
Nonblanching palpable purpura of the lower extremities
What is the microscopic appearance of this lesion?
Hives / urticaria
Increased vascular permeability due to IgE -> degranulation of mast cells -> dermal edema with mixed inflammatory infiltrate
What is the stomach pathology shown on the slide?
Signet-ring carcinoma (as opposed to the intestinal type)
What is the molecular cause of bullous impetigo?
Exfoliative toxin A produced by Staph aureus -> targeting of desmoglein -1 and formation of flaccid bullaeo
Also causes staphylococcal scalded skin syndrome
What is the diagnosis of this colon polyp?
Villous adenoma
What is the diagnosis? What is the microscopic appearance
Psoriasis
Disruption of epithelial barrier -> activation of dendritic cells -> T-helper cell activation - > hyperkeratosis + parakeratosis (retained nulcei in stratum corneum).
perivascular lymphocytes, ilated capillaries and acanthosis can also be seen.
What is the diagnosis? What is the microscopic presentation?
Buerger disease (thromboangiitis obliterans)
Small & medium vessel segmental vasculitis with inflammatory intraluminal thrombi which extends into veins & nerves and vessel wall sparing.
Presents with raynaud and superficial erythema and vein tenderness (thrombophlebitis)
What is this kidney tumor? If an individual has bilateral tumors like this, what is the most likely diagnosis?
Renal angiomyolipoma
Tuberous sclerosis
What is the diagnosis? What happens when plaques are removed?
How is it differentiated from Lichen Planus?
Plaque psoriasis
Lichen planus 5Ps palpable, polygonal, pruritic, purple/pink, planar, papules/plaques
