These answer explanations are and always will be free. However, given multiple email requests, I will post my Venmo (@Adam-Zakaria-SLO) if you want to send a few dollars to show your support for the website.
I also offer reasonably priced Study Guides and Personalized Study schedules, so please reach out using the Tutoring menu option or Study Guides and Personalized Study schedules menu option listed above if you would like personalized support.
Furthermore, I offer personal statement and application review services for residency applicants, so please reach out using the “Residency Advising and Application Preparation” menu option above if interested.
Lastly, please check out my Youtube channel (https://www.youtube.com/channel/UCT1Ukl4pm5QK9iw6h4MB_Hw/playlists) and the “Biostatistics Curriculum” option above for free videos and practice questions reviewing all the essential biostatistics topics covered on NBME exams. Good luck with your exams!
1) A 77-year-old woman with osteoporosis and hypertension is admitted to the hospital because of progressive confusion…
Recurrence of breast cancer
- Elderly woman with history of breast cancer presents with acute confusion, constipation and a corrected calcium of 15.6 with multiple skull metastases on CT, most concerning for hypercalcemia in the setting of breast cancer metastatic to bone
- Key idea: Most common cause of hypercalcemia in the outpatient setting is hyperparathyroidism, whereas most common cause in the inpatient setting is malignancy (which is highest on differential whenever calcium > 14 or so)
- Corrected calcium = Measured calcium + 0.8 * (4.0 – albumin)
- Albumin carries calcium, so if you have low albumin (less than normal of 4.0) it will make your serum calcium appear falsely low
- Hypercalcemia –> Stones (kidney stones), bones (bone pain), thrones (polyuria due to nephrogenic diabetes insipidus), groans (constipation and GI pain) and psychiatric overtones (anxiety, confusion, etc.)
2) A 62-year-old woman comes to the physician for a follow-up examination. Her blood pressure was 140/90…
Begin lisinopril therapy
- Middle-aged woman with diabetes mellitus presents with hypertension refractory to lifestyle changes and is found to have mild proteinuria, so should be immediately started on an ACE inhibitor or ARB in order to treat hypertension and, more importantly, slow progression of diabetic glomerulosclerosis
- Key idea: Diabetes leads to kidney disease by leading to preferential atherosclerosis of the efferent arteriole –> increased glomerular pressure –> chronic glomerular damage, and therefore the first sign of diabetic kidney disease is proteinuria rather than a drop in GFR (given early on diabetes will actually lead to an increase in GFR!)
- Key idea: ACE inhibitors and ARBs block angiotensin 2-mediated vasoconstriction of the efferent arteriole, and therefore basically counteract the renal effects of diabetes directly
3) A 23-year-old woman comes to the emergency department 2 hours after the sudden onset of sharp anterior chest pain…
Oral ibuprofen
- Young woman presents with acute sharp, pleuritic, chest pain and is found to have a friction rub with an ECG showing diffuse ST elevations and PR depressions, most consistent with pericarditis –> Best treatment is an NSAID such as ibuprofen
- Pleuritic chest pain differential:
- Pericarditis
- Pleuritis
- Pneumothorax
- Pulmonary embolus
- Common causes of pericarditis:
- Post-viral
- Uremia
- Lupus erythematosus
- Days after inflammation of heart (MI or CABG)
- ~6 weeks after inflammation of heart (MI or CABG) due to Dressler syndrome
- Chest pain that is Positional, Pleuritic, sharP, and reproduced by Palpation reduces the likelihood it is related to cardiac ischemia
4) A 77-year-old man comes to the physician because of a 3-month history of intermittent mild abdominal pain…
Adverse effect of verapamil
- Elderly woman who started verapamil 4 months ago presents with 3 months of intermittent abdominal pain with signs of constipation (external hemorrhoid, hard stool in rectal vault, increased stool burden on imaging) most likely due to an adverse effect from verapamil (calcium channel blocker)
- Side effects of calcium channel blockers:
- Constipation
- Hyperprolactinemia
- Gingival hyperplasia
- Leg swelling
- Diabetic gastropathy –> Postprandial nausea, bloating and nausea
5) A 62-year-old man with severe obstructive pulmonary disease has chronic disabling dyspnea. His pulse is…
Severity of hypoxemia
- Middle-aged man with severe COPD presents with progressive dyspnea and is found to have distended jugular veins, loud S2 and prominent pulmonary arteries on chest x-ray, concerning for pulmonary hypertension in the setting of chronic, diffuse lung disease (cor pulmonale)
- Key idea: Most capillaries in the body vasodilate in the setting of hypoxia, with the one exception being the lungs in order to minimize V/Q mismatch. However, in the setting of diffuse lung hypoxia (obstructive or restrictive lung disease) –> Diffuse vasoconstriction of pulmonary capillaries –> Increased afterload faced by right ventricle –> Pulmonary hypertension with signs of right-sided heart failure (LEE, JVP, hepatomegaly) without signs of left-sided heart failure (lung crackles)
- Key idea: Classic features of pulmonary hypertension include loud S2 and apical heave (due to hypertrophied right ventricle being most anterior heart structure)
6) A 62-year-old woman comes to the physician 8 days after she had loss of consciousness while combing her hair…
Subclavian steal syndrome
- Middle-aged woman with atherosclerotic risk factors (hypertension, smoking) presents following intermittent episodes of loss of consciousness associated with exertion of her left arm and is found to have absent radial and brachial pulses on the left, concerning for peripheral artery disease complicated by subclavian steal syndrome
- Key idea: Basic pathophysiology is that stenosis of the left subclavian artery means that when the left arm is exerted, there will be vasodilation of the capillary beds (in the setting of hypoxia) and this will cause blood destined for the posterior circulation of the brain to flow in a retrograde fashion towards the left arm, leading to cerebral hypoperfusion with resulting syncope
7) A 42-year-old man comes to the emergency department because of the recent onset of shortness of breath. He has smoked two…
Anaerobic empyema
- Young man with 50 pack-year smoking history presents with acute respiratory distress and is found to have dullness to percussion of the right lung based, leukocytosis and a confirmed pleural effusion on CXR that is drained to yield purulent, foul-smelling fluid, concerning for a possible empyema
- Key idea: Fact that collection is located in the right lower lobe increases suspicion for empyema secondary to aspiration event, which should increase suspicion for an anaerobic empyema
- Key idea: Both Strep pneumo and Staph aureus are common causes of empyema, but they are often seen as complications of a preceding lobar pneumonia (which is not the case here)
- Key idea: Empyema is basically an abscess of the pleural space given it is a collection of purulent material, and just like an abscess of the skin needs to be treated with an incision and drainage, an empyema needs to be drained with a chest tube
8) A 53-year-old man notices a lump in his neck. Examination shows a hard 2-cm nodule in the lower left pole…
Administration of calcium gluconate intravenously
- Middle-aged man who undergoes total thyroidectomy and then shortly thereafter develops facial numbness and tingling with laryngeal stridor and a positive Chvostek sign, concerning for post-operative hypocalcemia due to damage/removal of nearby parathyroid gland(s) –> Best immediate treatment is calcium gluconate to treat/reverse hypocalcemia
- Key idea: Endotracheal intubation not indicated given lack of shortness of breathe or hypoxia (hoarseness and stridor likely due to spasms in setting of hypocalcemia)
- Key idea: Hypocalcemia is a COMMON complication of thyroid surgery given the parathyroids lie very close to the thyroid gland (as the name implies)
9) A previously healthy 24-year-old woman comes to the physician because of an itchy rash on her face…
Inflammation caused by release of cytokines by effector and memory T lymphocytes
- Young woman presents with pruritic urticarial and vesicular rash of the face, upper extremities and hands 2 days after working in her garden, concerning for a possible contact dermatitis, which is a classic Type 4 hypersensitivity reaction (mediated by T cells)
- Common triggers of contact dermatitis:
- Poison oak/ivy
- Nickel
- Topical antibiotics
- Hair dyes
- Soaps/detergents
- Key idea: For the NBME exam, vesicular eruptions should make you think of viral infection (HSV, VZV, etc.), dermatitis herpetiformis and eczematous rashes (contact dermatitis, atopic dermatitis, etc.)
- Destruction of adhesion among epidermal cells caused by circulating IgG autoantibodies –> Pemphigus vulgaris –> Paraneoplastic syndrome characterized by widespread painful flaccid bullae/blisters with mucosal involvement
10) A 62-year-old woman comes to the physician because of increasingly severe pain of the fingers over the past…
Positive findings for anticentromere antibody
- Middle-aged woman presents with chronic history of Raynaud’s syndrome, GERD, tightening of the skin, telangiectasias, and soft tissue calcifications, with this constellation of symptoms being concerning for CREST syndrome (localized scleroderma) which is characterized by anticentromere antibodies
- CREST syndrome:
- Calcinosis cutis (soft tissue calcifications)
- Raynaud’s syndrome (cold exposure causing hands to turn white–>blue–>red)
- Esophageal dysmotility (dysphagia, GERD)
- Sclerodactyly (tight, shiny skin on the fingers)
- Telangiectasias
- On the NBME, lung crackles should make you concerned for pulmonary edema or interstitial lung disease (which is more likely in this case given association with scleroderma)
- Note: Diffuse scleroderma characterized by Anti-Scl-70 antibodies (anti-DNA topoisomerase I)
- Antineutrophil cytoplasmic antibody = C-ANCA = Granulomatosis with polyangiitis = Upper respiratory disease (nasal ulcers, ear ulcers) + Lower respiratory disease (hemoptysis) + Renal disease (glomerulonephritis)
- Anti-double stranded DNA –> Lupus
- Antiribonuclear antibody –> Mixed connective tissue disease –> Features of polymyositis, scleroderma and lupus
11) A 32-year-old man is brought to the emergency department 30 minutes after he was found unconscious on the floor…
Rhabdomyolysis
- Young man found down in setting of barbiturates overdose is found to have significantly elevated creatine kinase, hyperkalemia, metabolic acidosis, significant AKI with BUN:Creatinine ratio less than 15 and urinalysis notable for pigmented granular casts and positive dipstick for blood with few RBCs on microscopy, all of which points to rhabdomyolysis complicated by acute tubular necrosis
- Key idea: Rhabdomyolysis classically leads to positive urine dipstick for blood with no/few RBCs on urine microscopy because the dipstick test can return false positives in the setting of myoglobinuria (and hemoglobinuria)
- Key idea: BUN:Creatinine ratio greater than 20 points to pre-renal etiology (renal hypoperfusion), whereas a BUN:Creatinine ratio less than 15 points to an intrarenal etiology (acute tubular necrosis, acute interstitial nephritis, glomerulonephritis)
- Causes of rhabdomyolysis:
- Increased muscle exertion (seizure, exercise)
- Immobilization or crush injury
- Medications/toxins (statins, alcohol, etc.)
- Causes of Acute tubular necrosis:
- Severe ischemia (necrosis)
- Rhabdomyolysis
- Contrast nephropathy
- Heavy metals
- Aminoglycosides (gentamicin)
- Ethylene glycol
- Tumor lysis syndrome
- Acute interstitial nephritis –> Patient started on new drug (PPI, antibiotic, diuretic, NSAID) and then develops rash + fever + AKI with eosinophils and/or WBC casts in urine
- Glomerulonephritis –> Proteinuria and hematuria with RBC casts and/or dysmorphic RBCs
12) A 62-year-old man comes to the physician because of a 3-week history of progressive fatigue and shortness of breath…
Lisinopril
- Middle-aged man presents with subacute exertional shortness of breath and is found to have symptoms concerning for heart failure (bilateral basilar crackles, laterally displaced point of maximal impulse, decreased ejection fraction) and would therefore benefit from furosemide and an ACE inhibitor (lisinopril)
- Key idea: Medications shown to improve long-term survival among individuals with heart failure include ACE inhibitor or ARB, beta-blockers (carvedilol, metoprolol succinate, bisoprolol) and aldosterone antagonists (spironolactone), with ACE inhibitors often looked upon most favorably in the setting of acute decompensated heart failure (such as this patient who is volume overloaded)
- Note: Spironolactone is the first-line diuretic among patients with volume overload in the setting of cirrhosis
13) A 26-year-old man is brought to the emergency department after vomiting bright red blood twice…
Intravenous administration of 0.9% saline
- Young man presents following two episodes of hematemesis (potentially in setting of Mallory-Weiss tear) and is found to be tachycardic with low-normal blood pressure, and therefore would likely benefit from some fluid resuscitation with 0.9% normal saline
- Key idea: In all patients, first priority is the ABCs of Airway (can patient protect airway?), Breathing (is patient breathing normally?), and Circulation (does patient seem well-perfused?)
- Key idea: Fluid resuscitation should always be performed with an isotonic fluid such as 0.9% normal saline and lactated ringers
- Key idea: In setting of acute blood loss, the hematocrit/hemoglobin may initially appear normal given they are concentration measures rather than absolute measures
14) A 24-year-old woman has had intermittent fever, malaise, and a generalized rash for 2 weeks. Her temperature is 37.2 C…
Jarisch-Herxheimer reaction
- Young woman presents with fever, generalized maculopapular rash over palms and soles and patchy alopecia (concerning for syphilis). She receives treatment with penicillin G and then shortly thereafter develops chills, headache, tachycardia, flushing and fever, concerning for the Jarisch-Herxheimer reaction
- Key idea: Jarisch-Herxheimer reaction commonly seen soon after initiating treatment for spirochete infections (syphilis, lyme disease, etc.) and occurs due to the release of endotoxin-like substances from microorganisms as they are killed
- Meningococcemia –> Fever, neck stiffness, photophobia, petechial/purpuric rash
- Rocky Mountain spotted fever –> Fever, myalgias, confusion, petechial/purpuric rash starting on palms/soles and spreading to body
- Toxic shock syndrome –> Patient with nasal packing or prolonged tampon usage who presents with fever, hypertension and diffuse erythroderma
15) A 47-year-old man comes to the physician because of a 1-month history of progressive swelling of both legs and generalized…
Renal biopsy
- Middle-aged man with history of IVDU and chronic hepatitis B and C presents with subacute lower extremity edema and is found to be hypertensive with significant proteinuria and hematuria, concerning for a possible glomerulonephritis that should be worked up with a renal biopsy
- Key idea: Chronic hepatitis infections associated with cryoglobulinemia and membranoproliferative glomerulonephritis, both of which can lead to glomerulonephritis
- Urine protein electrophoresis –> Multiple myeloma –> Hypercalcemia, back pain, anemia, renal disease
- Cystoscopy –> Unexplained hematuria or urinary symptoms in a smoker (looking for bladder cancer)
16) A previously healthy 37-year-old woman comes to the physician because of a 2-year history of progressive shortness of breath…
Insufficient inhibition of neutrophil elastase
- Young woman with 5 pack-year smoking history and a family history of emphysema development at a young age presents with progressive dyspnea and wheezing and is found to have a low FEV1 on pulmonary function tests and CXR showing hyperinflated lungs, concerning for alpha-1 antitrypsin deficiency complicated by COPD
- Key idea: Neutrophil elastase is a protease that can lead to breakdown of alveoli and is typically inhibited by the anti-protease enzyme alpha-1 antitrypsin, so patients who lack alpha-1 antitrypsin will have accelerated destruction of alveoli (especially in setting of tobacco use) –> early-onset COPD
- Key idea: Alpha-1 antitrypsin classically leads to early-onset COPD and cirrhosis without significant exposures to the typical risk factors
- Key idea: Obstructive lung diseases are due to problems getting air out (i.e., decreased elasticity of lungs or highly turbulent airflow upon expiration) and therefore lead to hyperinflated lungs (asthma, COPD, bronchiectasis)
- Key idea: Restrictive lung diseases are due to problems getting air in (i.e., lungs are excessively stiff or diaphragm is weak) and therefore leads to small lungs (interstitial lung diseases, neuromuscular weakness, etc.)
17) A 24-year-old woman, gravida 2, para 2, comes to the emergency department because of an uncontrollable nosebleed…
Corticosteroid therapy
- Young woman presenting with recurrent mucosal bleeding and petechiae (both concerning for a platelet problem) is found to be thrombocytopenic with megakaryocytes in the bone marrow, most consistent with immune thrombocytopenic purpura (i.e., platelets are being produced but then being destroyed by circulating antibodies)
- Key idea: First line treatment of ITP is corticosteroids, followed by IVIG, and lastly splenectomy if the patient is highly refractory (eliminates primary source of antibody production and destruction)
- Key idea: If patient has clinical aspects of a platelet disorder (mucosal bleeding, petechiae, etc.), then first branch point is whether they have a Quantitative or Qualitative platelet disorder:
- Quantitative(decreased platelet count, prolonged bleeding time)
- Immune thrombocytopenic purpura: Often seen in young people (autoimmune disease), leads to isolated thrombocytopenia (unless it’s a component of SLE)
- Aplastic anemia: Pancytopenia, often associated with cancer or prior radiation
- Qualitative(normal platelet count, prolonged bleeding time)
- Uremia: Indication for dialysis!
- von Willebrand disease: Often presents since childhood/adolescence, may have mildly prolonged aPTT given vWF is a carrier protein for Factor 8
- Quantitative(decreased platelet count, prolonged bleeding time)
18) A 52-year-old woman comes for a routine health maintenance examination. She feels well. Over the past 6 months…
Weight loss
- Key idea: Two most important risk factors for osteoarthritis are advanced age (non-modifiable) and obesity (modifiable)
19) A 62-year-old man comes to the physician for a preoperative evaluation. He is scheduled to undergo partial colectomy…
No further tests are indicated
- Middle-aged man scheduled for an impending partial colectomy has evidence of mild aortic stenosis and mild mitral regurgitation, but has no symptoms of ischemic heart disease (i.e., chest pain or dyspnea brought on by exertion that is relieved by rest or nitrates) and therefore does not require further cardiac work-up prior to surgery
20) A 57-year-old man comes to the emergency department because of a painful, cold right leg for 4 hours…
Hydration
- Middle-aged man with atherosclerotic risk factors presents with an acutely painful and cold leg and has an angiography of the right leg performed that is complicated by a significant increase in creatinine. This picture is concerning for contrast nephropathy, with the risk of this complication being decreased by hydration prior to the imaging procedure
- Key idea: Many cases of contrast nephropathy will self-resolve, but in serious cases can progress to acute tubular necrosis
- Pretreatment with prednisone and diphenhydramine –> Reduces risk of urticarial and anaphylactic drug reactions
- Discontinuation of metformin often performed in hospitalized patients due to risk of lactic acidosis (AG metabolic acidosis)
21) A 67-year-old man with type 2 diabetes mellitus comes to the physician because of a 2-day history of increasing pain and redness…
Prepatellar septic bursitis
- Elderly man who recently spent significant time on his knees presents with acute progressive pain and redness of his left knee and fever, with exam demonstrating fluctuance ANTERIOR to the patella that is concerning for prepatellar bursitis
- Key idea: Next best step would be bursal fluid aspiration, with treatment either being NSAIDS in setting of uncomplicated disease versus drainage and systemic antibiotics in setting of complicated disease
- Inflamed Baker cyst –> Erythema, swelling and pain BEHIND the knee
- Inflammatory bursitis of the pes anserinus –> Erythema, swelling and pain of the PROXIMAL MEDIAL SHIN
- Osgood-Schlatter disease –> Adolescent with pain and bony protuberance over the ANTERIOR PROXIMAL TIBIA
22) A 52-year-old woman with hypertension and type 2 diabetes mellitus is admitted to the hospital because of a…
Acyclovir
- Middle-aged woman presents with acute progressive confusion and fever with brain MRI demonstrating temporal lobe hemorrhage/edema concerning for HSV encephalitis –> Treat with acyclovir
- Key idea: HSV specifically leads to temporal lobe disease because it primarily results from oropharyngeal infection that travels via the olfactory tract to the olfactory cortex, which is located in the temporal lobe
- Encephalitis: Fever + Altered mental status
- Meningitis: Fever + meningismus (stiff neck, headache) + photophobia
- Ceftriaxone –> Bacterial meningitis
- Dexamethasone –> Brain tumor
- Low-molecular-weight heparin –> Stroke
- Mannitol –> Significant brain edema
- Pyrimethamine-sulfadiazine –> Toxoplasmosis (ring-enhancing lesion in immunocompromised patient)
23) Two days after a myocardial infarction, a previously asymptomatic 60-year-old woman develops pulmonary edema…
Ruptured papillary muscle
- Middle-aged woman who develops acute pulmonary edema and a systolic murmur over the apex 2 days after an MI, concerning for papillary muscle rupture c/b mitral regurgitation
- Key idea: Post-MI complications involving rupture (papillary muscle, free wall, interventricular septum) often occur 2-5 days after MI because that is when those structures would be most damaged and most prone to rupture
- Key idea: Papillary muscle rupture most commonly seen following an inferior MI (leads 2, 3 and aVF) because the right coronary artery feeds the posteromedial papillary muscle
- Key idea: Slow onset mitral regurgitation can often be tolerated by the heart, but the heart (and basically every other part of the body) does not respond well to an acute change in demand/stress, leading to flash pulmonary edema
- Holosystolic apical murmur over apex radiating to axillae –> Mitral regurgitation
- Diastolic murmur over apex –> Mitral stenosis
- Systolic ejection murmur in upper sternal border radiating to carotids –> Aortic stenosis
- Decrescendo diastolic murmur in upper sternal border –> Aortic regurgitation
24) A 47-year-old woman comes to the physician because of a 2-day history of soreness in the back of her throat and pain…
Airway compromise
- Middle-aged woman with history of recurrent episodes of tonsillitis presents with odynophagia with massive edema and purulence of the soft palate and tonsils, putting patient at increased risk for airway compromise
- Common indications for intubation:
- Expanding hematoma, swelling or emphysema in neck (risk of airway obstruction)
- Glasgow-Coma score of 8 or less (eight and intub-eight) [risk of not protecting airway]
- Severe inhalation injury (i.e., breathing smoke during house fire)
- Breathing is noisy or gurgly
25) An asymptomatic 32-year-old woman with HIV infection comes to the physician as a new patient. Her last…
Pap smear and P. jiroveci prophylaxis
- Key idea: Patients with HIV should receive an annual pap smear (given immunocompromise –> chronic HPV infection –> increased risk of cervical CA)
- CD4 < 200 –> TMP-SMX for PJP/PCP prophylaxis
- CD4 < 100 –> TMP-SMX for toxoplasmosis prophylaxis
- CD4 < 50 –> Azithromycin for Mycobacterium avium complex (MAC) prophylaxis
- Mammography –> Every 2 years starting at 50 years old
26) A 62-year-old woman has had progressively severe midback pain over the past month. She has been fatigued and…
Serum protein electrophoresis
- Middle-aged woman with subacute back pain and confusion is found to have anemia, hypercalcemia and renal dysfunction with lateral skull x-ray showing dark, osteolytic lesions most concerning for multiple myeloma –> work-up with serum protein electrophoresis (SPEP)
- Key idea: Whenever you see the combination of hypercalcemia and renal dysfunction you should think of multiple myeloma given that renal dysfunction typically leads to hypocalcemia (decreased vitamin D activation and increased circulating phosphate to bind up calcium)
- Key idea: Patients with multiple myeloma will very commonly be anemic given that the over production of plasma cells occurs in the bone marrow and would impede normal RBC production
27) A previously healthy 52-year-old man comes to the physician because of a 6-month history of cough productive of…
Alveolar destruction and fibrosis
- Middle-aged man with 25 pack-year smoking history presents with chronic cough and is found to have prolonged expiratory phase with an FEV1:FVC ratio less than 0.7, consistent with an obstructive lung disease such as COPD which is caused by alveolar destruction
- Key idea: Obstructive lung diseases occur when there is trouble getting air out of the lungs, which can happen in COPD because patients have destruction of their alveoli and the alveoli are what provide elasticity of the lung and help the lungs collapse inward during expiration
- Diffuse infiltrative disease of the lung parenchyma –> Interstitial lung disease –> Restrictive lung disease (decreased lung volumes)
28) A 35-year-old man had recurrent episodes of dysuria and pelvic pain over the past 2 years. He is sexually…
Chlamydia trachomatis
- Young sexually active man presents with recurrent episodes of dysuria and pelvic pain and is found to have prostate tenderness and sterile pyuria (WBCs in urine with negative urine culture), concerning for chronic prostatitis
- Key idea: Prostatitis in a young man (<35 years old) is often due to Chlamydia or Neisseria gonorrhea, whereas prostatitis in an older man (>35 years old) is often due to Gram negative bacteria (such as E. coli)
- Key idea: Sterile pyuria (positive WBCs in urine but negative urine culture) is classically seen in cervicitis (in women), chronic prostatitis (in men) and urethritis (both)
- Chancroid –> Painful ulcerative genital lesion
- Herpes simplex –> Painful vesicular genital lesions or shallow ulcers
- Syphilis –> Painless genital ulcer (chancre) + lymphadenopathy
29) A 37-year-old woman with type 1 diabetes mellitus and anxiety disorder comes to the physician because of a 6-month…
Syringomyelia
- Young woman presents with chronic progressive loss of pain and temperature sensation over forearms, hands and upper back with increased deep tendon reflexes globally, concerning for a possible syringomyelia
- Key idea: Syringomyelia is a cystic cavity within the central canal of the spinal cord and classically leads to loss of pain and temperature sensation in a “cape-like” distribution over the bilateral arms and upper back because it blocks the spinothalamic fibers from crossing over within the spinal cord
- Note: Does not lead to motor symptoms or loss of fine touch/proprioception because those fibers cross in the medulla rather than within the spinal cord
- Key idea: Syringomyelia classically associated with Chiari 1 malformations, trauma and tumors
30) A 32-year-old woman comes to the emergency department because of fever and cough with increasing production…
Allergic bronchopulmonary aspergillosis
- Young woman with atopic history presents with recurrent episodes of fever, cough and purulent sputum associated with a poorly resolving lung infiltrate and is found to have Aspergillus fumigatus on sputum culture, concerning for allergic bronchopulmonary aspergillosis
- Aspergillosis can lead to several distinct pulmonary pathologies:
- Allergic bronchopulmonary aspergillosis: Patient with asthma or cystic fibrosis who presents with recurrent fleeting infiltrates associated with eosinophilia due to hypersensitivity response to Aspergillus; treat with months of itraconazole and oral steroids
- Angioinvasive aspergillosis: Immunocompromised patient who presents with fever, chest pain and hemoptysis with imaging demonstrating a halo sign (ground glass opacity surrounding nodule); treat with voriconazole and caspofungin
- Chronic pulmonary aspergillosis: Patient with history of cavitary lung disease (tuberculosis, aspiration, Klebsiella) who presents with chronic weight loss, cough and hemoptysis and is found to have a cavitary lung lesion with a fungal ball (aspergilloma); treat with surgical resection +/- azole medication
- Cystic fibrosis –> Recurrent sinopulmonary infections + Fat malabsorption with weight loss + Bronchiectasis
- Alpha-1 antitrypsin deficiency –> COPD and cirrhosis in a young patient with family history
- Pertussis –> 1-2 weeks of cold-like symptoms followed by intermittent bouts of violent coughing (post-tussive vomiting, subconjunctival hemorrhages, etc.)
31) A 52-year-old woman has decreased urine output 6 hours after admission for treatment of a 3-day history…
Acute tubular necrosis
- Middle-aged woman with possible diabetic gastroparesis presents with nausea/vomiting complicated by hypotension and is found to have an acute increase in her creatinine with coarse granular casts concerning for possible acute tubular necrosis
- Key idea: Hypotension/dehydration will often initially lead to a pre-renal acute kidney injury, but in setting of severe or prolonged hypotension/dehydration patients can develop acute tubular necrosis (form of intrarenal acute kidney injury)
- Note: Typical way to differentiate between pre-renal AKI vs ATN is by looking at BUN:Cr ratio (often >20 in pre-renal AKI and <15 in intra-renal AKI) and presence of granular (“muddy brown”) casts that is suggestive of acute tubular necrosis
- Acute glomerulonephritis –> Proteinuria and hematuria with RBC casts and/or dysmorphic RBCs
- Acute interstitial nephritis –> Patient started on a new medication (antibiotic, diuretic, PPI, NSAID) who presents with fever + rash + AKI
- Rhabdomyolysis –> Positive dipstick for blood with no/few RBCs on microscopy (due to myoglobinuria leading to false-positive dipstick) with elevated creatine kinase, hyperkalemia and hyperphosphatemia
32) A 37-year-old man comes to the emergency department because of vomiting for the past 3 days. He says that he cannot hold…
Decreased K+, Decreased Cl- and Increased pH
- Young man with recurrent vomiting with dry mucous membranes who will likely have a hypokalemic, hypochloremic, metabolic alkalosis due to recurrent vomiting
- Key idea: Patients with excessive vomiting develop hypochloremia and metabolic alkalosis because they are losing stomach acid (which is HCL = H+ with Cl-)
- Key idea: Patients with excessive vomiting –> hypovolemic –> RAAS overactivation –> Increased aldosterone activity –> Increased reabsorption of Na+ from collecting duct in exchange for K+ and H+ –> Contraction alkalosis with hypokalemia
33) A 62-year-old man is admitted to the hospital for treatment of pneumonia. He has a 3-day history of fever…
Metformin
- Middle-aged man with history of type 2 diabetes mellitus and coronary artery disease is admitted for pneumonia with labs concerning for an anion gap metabolic acidosis, and should therefore have his metformin discontinued due to risk of lactic acidosis in setting of sepsis/hypotension
- Anion gap = [Na+] – [Cl-] – [HCO3-], with an AG >12 being consistent with an anion gap metabolic acidosis
- Differential for anion gap metabolic acidosis [MUDPILERS]:
- Methanol (associated with ocular/eye symptoms)
- Uremia
- DKA
- Propylene glycol
- Isoniazid/Iron
- Lactic acidosis
- Ethylene glycol (associated with kidney disease)
- Rhabdomyolysis
- Salicylate toxicity (early respiratory alkalosis –> anion gap metabolic acidosis can lead to a normal overall pH)
34) A 57-year-old man comes to the physician because of a 3-month history of mild shortness of breath with exertion…
Switch from glyburide and metformin to intermediate-acting insulin
- Middle-aged man with history of type 2 diabetes treated with oral medication (metformin, glyburide) presents with chronic exertional shortness of breathe and is found to have hypertension and a hemoglobin A1c > 9%, meaning they could probably benefit from addition of basal insulin
- Key idea: Goal HgbA1c in patients with type 2 diabetes is below 7%, but often a level 8% is tolerable especially in older patients where the risks of hypoglycemia carry more weight
- Step-up therapy for diabetes management:
- 1st: Lifestyle changes
- 2nd: Metformin
- 3rd: Metformin + Oral antidiabetic agents (glipizide) or GLP-1 analogue (exenatide)
- 4th: Metformin + basal insulin
- 5th: Basal-bolus insulin therapy
35) A 55-year-old woman comes to the emergency department because of fever, nausea, vomiting, diarrhea, and decreased…
Prerenal azotemia
- Middle-aged woman with acute vomiting and diarrhea presents with decreased urine output and is found to have orthostatic hypotension, tachycardia, and dry mucous membranes with a BUN:Creatinine ratio >20 and urine Na+ level < 20, both of which are compatible with pre-renal AKI
- Key idea: Hypotension/dehydration can lead to either a pre-renal AKI or acute tubular necrosis (form of intra-renal AKI) with a pre-renal AKI being favored if urine concentrating functions of the kidney appear preserved, which is suggested by BUN:Cr ratio > 20, urine Na+ < 20 and a FeNa < 1% because these lab findings all suggest Na+ is being reabsorbed effectively to try to preserve volume status
- Note: Orthostatic hypotension diagnosed if a patient moves from lying to sitting or sitting to standing and has a drop in systolic BP of at least 20 mm Hg and/or a drop in diastolic BP of at least 10 mm Hg
36) A 42-year-old man with alcoholism is admitted to the hospital 12 hours after the onst of severe epigastric pain that…
Serum calcium concentration
- A young man with alcohol use disorder presents with symptoms concerning for acute pancreatitis (epigastric pain radiating to back with amylase at least 3X above upper limit of normal), with patient’s hypocalcemia portending a poor prognosis
- Key idea: Hypocalcemia in the setting of acute pancreatitis is indicative of a high degree of fat saponification in the setting of fat necrosis of peripancreatic fat and carries a poor prognosis both because it indicates significant disease burden and because hypocalcemia can lead to additional morbidity
- Key idea: Two most common causes of pancreatitis are alcohol and gallstones, and therefore if patient denies alcohol use then next best step is right upper quadrant ultrasound to look for gallstones (HIGH YIELD!!!); if RUQ U/S is negative, next set of lab tests would be calcium level and lipid studies (looking for hypertriglyceridemia)
- Full differential for pancreatitis remembered by I GET SMASHED:
- Idiopathic
- Gallstones
- EtOH
- Trauma (motor vehicle accident, hitting stomach on bike handles, etc.)
- Steroids
- Mumps (parotitis, pancreatitis and orchitis)
- Autoimmune
- Scorpion sting
- Hypertriglyceridemia/Hypercalcemia
- ERCP
- Drugs (diuretics, HIV drugs, etc.)
37) A 62-year-old man comes to the physician because of moderate right leg pain for 2 days. He has metastatic non-small cell…
Subcutaneous administration of enoxaparin
- Middle-aged man with known history of lung cancer presents with moderate right leg pain with a positive DVT ultrasound –> best treatment is heparin (enoxaparin)
- Key idea: Thrombolytics (alteplase) are only given in a patient with DVT and signs/symptoms concerning for a PE (chest pain, dyspnea, hypoxia, tachycardia)
- Key idea: Patients are initially given heparin and then bridged to warfarin to reduce likelihood of warfarin-induced skin necrosis due to selective inhibition of proteins C and S (anti-thrombotic proteins) seen with initial warfarin administration
- Key idea: IVC filters are generally unfavored given they can become infected or become a nidus for clot formation and are typically only reserved for patients for whom anticoagulants are contraindicated (history of massive GI bleed, hemorrhagic stroke, etc.)
38) A previously healthy 22-year-old man is brought to the emergency department 1 hour after he was hit in his right flank…
No further testing is indicated
- Key idea: Patient has stable hematocrit, no rebound/guarding, stable vitals and no urinary changes
- Key idea: Patients with flank trauma who develop hematuria, severe flank tenderness and expanding flank ecchymosis should receive a CT scan
39) A 24-year-old woman, gravida 1, para 1, comes to the physician because of a 3-month history of fatigue. Menses occur…
Iron
- Young woman with normal menses presents with chronic fatigue, pale conjunctivae, anemia and blood smear demonstrating hypochromic RBCs most consistent with iron deficiency anemia
- Key idea: Most common cause of shortness of breathe and anemia in young women is iron deficiency anemia in setting of menstrual blood losses (even if menses are normal)
- Hypochromic RBCs –> Enlarged areas of central pallor
- Folate deficiency –> Megaloblastic anemia (MCV > 100 with hypersegmented neutrophils (5+ nuclear lobes))
- Niacin deficiency –> Pellagra (Diarrhea, Dermatitis, Dementia)
- Thiamine deficiency –> Wernicke encephalopathy (confusion, ataxia, ophthalmoplegia)
- Vitamin B6 (pyridoxine) deficiency –> Peripheral neuropathy, almost exclusively seen among patients receiving isoniazid for mycobacterial infection
40) A moderately obese 35-year-old woman has a 4-year history of recurrent abscesses in both axillae. These are…
Surgical excision of apocrine tissue
- Young obese woman with chronic history of recurrent painful abscesses in both axillae concerning for hidradenitis suppurativa –> Definitive treatment includes surgical removal of apocrine glands given that disease originates from the apocrine glands
- Key idea: Two most important risk factors for hidradenitis suppurativa include obesity and tobacco use
41) A 37-year-old woman comes to the physician because she has been amenorrheic for 3 months. She has also had…
Urine free cortisol concentration in a 24-hour specimen
- Young woman presents with chronic history of secondary amenorrhea, hirsutism, massive weight gain, hypertension, and truncal obesity concerning for Cushing syndrome, which can be diagnosed by:
- Increased 24-hour urine free cortisol
- Increased late night salivary cortisol
- Inadequate low-dose (1 mg) overnight dexamethasone suppression test
- Key idea: After Cushing syndrome is diagnosed, next best test is ACTH level because that can tell you whether you’re dealing with ACTH-dependent forms of Cushing syndrome due to ACTH-producing pituitary tumor (Cushing disease) or ACTH-producing tumor elsewhere (small cell carcinoma), or whether you’re dealing with ACTH-independent forms of Cushing syndrome such as exogenous steroid usage or adrenal hyperplasia/carcinoma
- Note: Elevated DHEA SULFATE is indicative of increased androgen production from the adrenal glands and is often concerning for adrenal hyperplasia or adrenal carcinoma (which can lead to ACTH-independent form of Cushing syndrome)
42) A 67-year-old white man comes to the physician because his wife is concerned about a freckle on the back of his neck…
Full thickness biopsy
- Elderly white man presents with changing, multi-colored, large (>6 mm), asymmetric pigmented lesion with unclear borders, concerning for a possible melanoma that should be worked up with a full thickness biopsy
- Key idea: Concerning features of pigmented lesions can be remembered by ABCDE‘s:
- Asymmetric
- Unclear/irregular Borders
- Multiple Colors
- Diameter > 6 mm
- Evolution
- Key idea: Shave biopsy is NOT appropriate in the setting of possible melanoma because you want to assess depth of invasion (Breslow thickness) in order to determine appropriate margins for full excision
43) A 77-year-old man is brought by his wife for a follow-up examination 3 weeks after an episode of right middle lobe pneumonia…
Swallowing study
- Elderly man with history of vascular dementia, MMSE of 20 and recent right middle lobe pneumonia endorses increased coughing after meals with dysarthria on exam, concerning for possible oropharyngeal dysphagia that should be worked up with a swallowing study
- Key idea: Aspiration tends to predominately affect the right lung given that the right mainstem bronchus is shorter, wider and more vertical than the left mainstem bronchus
- Two main forms of dysphagia include:
- Oropharyngeal dysphagia: Difficulty initiating swallowing associated with coughing choking, aspiration or nasal regurgitation
- Often secondary to stroke, dementia, oropharyngeal malignancy or neuromuscular disorder
- Work-up with videofluoroscopic modified barium swallow (swallow study)
- Esophageal dysphagia: Sensation of food getting stuck in esophagus a few seconds after swallowing
- Dysphagia to solids and liquids –> Likely motility issue –> Barium swallow or esophageal manometry
- Dysphagia to solids progressing to liquids –> Likely esophageal obstruction (malignancy, stricture, esophageal web) –> Upper endoscopy >> Barium swallow
- Oropharyngeal dysphagia: Difficulty initiating swallowing associated with coughing choking, aspiration or nasal regurgitation
- Dementia should be suspected in patient with MOCA < 26 and/or MMSE < 24
44) A 77-year-old woman comes to the physician because of a 3-weekhistory of light-headedness. She states that she feels…
Ambulatory ECG monitoring
- Elderly woman with subacute history of light-headedness upon standing who is found to have an irregularly irregular heart rate with EKG confirmed atrial fibrillation and no orthostatic hypotension who would benefit from home/ambulatory ECG monitoring to make sure she is not having bouts of Afib with rapid ventricular rate or another more malignant rhythm
- Key idea: Her history of dizziness upon standing sounded like potential orthostatic hypotension, but she did not meet criteria (systolic BP drop > 20 mm Hg or diastolic BP drop > 10 mm Hg upon moving from sitting to standing)
- Syncope is caused by hypoperfusion of the brain, with potential causes including vasovagal and carotid hypersensitivity, hypovolemia, or problems with the heart pumping blood forward (impaired contractility, arrhythmia, severe aortic stenosis or outflow obstruction, etc.)
- Exercise stress test –> Most useful in setting of potential cardiac ischemia (exertional chest pain or dyspnea)
45) A 32-year-old man comes to the physician because of a 4-week history of moderate numbness and weakness of his left hand…
Ulnar nerve compression
- Young man with subacute numbness and weakness of his left hand with atrophy of the hypothenar muscles and “claw hand” deformity of fingers 3, 4 and 5 with weak finger abduction and decreased sensation over the palmar aspects of fingers 4 and 5, most concerning for an ulnar nerve compression
- Key idea: Ulnar nerve is most commonly compressed at the elbow (person working at computer or truck driver putting pressure on elbow all day), but the presence of an ulnar claw points to compression at the wrist (loss of proximal finger extensors with intact distal finger flexors)
- Key idea: C8 nerve root provides similar sensory input as the ulnar nerve, but is primarily responsible for finger flexion so a C8 nerve root compression would lead to loss of finger flexion rather than an “ulnar claw” (where fingers are permanently flexed)
46) A study is conducted to compare a new stool test with mucosal biopsy for diagnosing Helicobacter pylori infection...
80%
47) A 72-year-old man comes to the physician for a routine examination. He has a 1-year history of hypertension controlled…
Cigarette smoking
- Key idea: #1 risk factor for atherosclerotic diseases is cigarette smoking, followed by diabetes
- Key idea: #1 risk factor for stroke is hypertension
- Key idea: Increased weight is #1 risk factor for osteoarthritis
48) A previously healthy 27-year-old intern comes to the emergency department 5 minutes after she was stuck in the…
Washing the area of involvement
- Young woman immunized against hepatitis B was stuck by a needle used on a patient with AIDS who has labs demonstrating they do not have active hepatitis B, and therefore should carefully wash the area of involvement and then start post-exposure prophylaxis against HIV within 72 hours (but the earlier the better!)
- Key idea: Young woman is immunized against hepatitis B and the patient did not have active hepatitis B, so no post-exposure prophylaxis against hepatitis B is needed
- Note: If a patient is stuck with a needle used on a patient with hepatitis C, no post-exposure prophylaxis is indicated given there are no effective agents and the risk of transmission is very low
49) A 72-year-old woman comes to the physician because of a 6-day history of increasingly severe left hip pain. She now has difficulty…
Avascular necrosis
- Elderly woman currently taking prednisone who presents with increasingly severe left hip pain with significant pain with weight bearing and hip MRI demonstrating crescent sign of left hip, most consistent with avascular necrosis due to steroid use
- Key idea: Hip pain with inability to bear weight often makes me think of avascular necrosis or septic arthritis (if patient is also febrile)
- Causes of avascular necrosis can be remembered by CAST Bent LeGS:
- Corticosteroids
- Alcoholism
- Sickle cell disease
- Trauma
- “the Bends” –> Rising too quickly while deep sea diving –> precipitation of air bubbles that can occlude blood vessels
- Legg-Calve Perthes –> Idiopathic avascular necrosis of the hip seen in 5-7 year olds
- Gaucher disease (lysosomal storage disease with similar features to sickle cell disease)
- Slipped capital femoral epiphysis (SCFE) –> Overweight adolescent
50) A healthy 39-year-old man of German descent comes for a routine examination. He had a cholecystectomy at the age of 25…
Abnormal red blood cell membrane
- Young man of European descent with history of cholecystectomy at young age and intermittent jaundice presents with splenomegaly and normocytic anemia with increased mean corpuscular hemoglobin concentration (MCHC), negative Coombs test and spherocytes (erythrocytes with loss of central pallor), all of which point towards hereditary spherocytosis (due to abnormal red blood cell membrane)
- Key idea: Spherocytes can be seen in hereditary spherocytosis and autoimmune hemolytic anemia, with the key distinguishing factor being the Direct Coombs test
- Key idea: Increased MCHC is a fairly specific finding for hereditary spherocytosis
- Key idea: Most commonly seen in patients of Northern European descent with family history of splenectomy (autosomal dominant condition), and commonly leads to biliary pathologies due to chronic hemolysis leading to pigment gallstones
- Treatment: Folate supplementation (due to chronic hemolysis) + Splenectomy (given that cells are being destroyed in the spleen)
We are not affiliated with the NBME, USMLE or AAMC.
The answer explanations may not be reproduced or distributed, in whole or in part, without written permission of Step Prep.