Dewdrop on a rose petal appearance in a CN V1 dermatomal distribution. Rash is painful and weeping. Immunocompromised host (s/p chemo)

Wrong answers

Impetigo: honey colored crusting lesion related to group A strep infection

Pyoderma gangrenosum: think green cheese; usually a single large round ulcer. Rapidly progresses from small papule or pustule to large painful ulcer with purulent, violaceous border. Associated with IBD (crohn disease, UC, RA, trauma). Most commonly lower limbs.

Syphilis: Causes a few types of skin lesions: chancre, gummas, etc. Chancre: most common, painless, genital. Doesn't really fit the story here anyway.

SLE: doesn't fit

Meets the 5 FAT RN criteria:

• fever
• anemia
• thrombocytopenia
• renal symptoms
• neuro symptoms

Also, Indirect hyperbilirubinemia and increased LDH should tip you off to MAHA

Intermittent polyarthritis with positive ANA (sensitive but not specific) and anti-DNA (very specific) means lupus. You don’t even need the non-painful mouth ulcers.

Anesthesia to the anterolateral thigh is the distribution of the lateral femoral cutaneous nerve. LFC neuropathy can be caused by compression near the inguinal ligament (say, from a hematoma). Note that it’s the compression of the nerve that causes decreased sensation, not the hematoma itself.

Recurrent infections with abscesses should raise the suspicion of chronic granulomatous disease. Suppurative arthritis does even more, if you’re likely to remember that. The real diagnosis is made from the Step 1 style question. Nitroblue tetrazolium is the test used to diagnose CGD, which is a defect in NADPH oxidase (the oxidative burst that kills Staph aureus).

Unstable and hypotensive patients after blunt trauma get laparotomies (don’t put an unstable patient in the CT scanner). In addition to saline and blood products, definitive surgery is how you address the C in ABC.

Alcohol raises GGT. The other liver enzyme lab to remember is the 2:1 or greater AST/ALT ratio associated with alcoholic liver disease.

The patient has a small bowel obstruction, likely due to adhesions from prior surgery, evident clinically and confirmed by radiograph (grossly dilated small bowel without distal colonic dilation to suggest paralytic ileus). Conservative treatment in a stable patient involves NG tube decompression and NPO. A CT can be obtained for further characterization and to look signs of bowel compromise (and would be in real life), but there is no reason to delay appropriate care to get it.

Proximal muscle weakness + skin findings = dermatomyositis. Yes, kids can get this. In this case, they’ve gone to the trouble of describing Gottron’s papules (“flat-topped red papules over all knuckles”) and the heliotrope rash (purple-red discoloration over the eyelids). Please note the USMLE will never actually say things “heliotrope” on the actual exam. They always describe.

Dermatomal rash means zoster (a chickenpox/varicella reactivation disease). Immune insults, like chemotherapy, predispose to zoster flares.

The STD that forms a painful ulcer aka chancroid = H ducreyi (ducreyi makes you cry, as they say).

This is a keratoacanthoma.

It's a cup shaped squamous cell carcinoma that's filled with keratin debris. It rapidly grows then usually spontaneously regresses. But, it's still an SCC, so we should excise.

The thing you do with things that look like skin cancer is excise them completely.

Lisinopril and especially spironolactone (a K-sparing diuretic) can both cause hyperkalemia. Renal failure (severe AKI or ESRD) is also a major cause of hyperkalemia, but not in this case with the only mildly elevated Cr and BUN levels.

The video shows a normal Moro reflex. This is a primitive "hang on for your life!" reflex.

Asymmetric Moro is associated with clavicle fracture or brachial trauma 2/2 shoulder dystocia.

Again, acute RUQ pain (especially in an obese woman) should set off the gallstone alarms. Fever and other systemic signs, white count, etc lead you down the acute cholecystitis. Simple pain leads you to symptomatic cholelithiasis. Either way the first step is to get a RUQ sono to see those stones! HIDA is used as an adjunctive study in cases of cholelithiasis to assess for cystic duct obstruction (and thus likely acute cholecystitis) in equivocal cases.

Post-traumatic AV fistula! Just like dialysis AV fistulae have bruits and thrills, so do non-purposefully created ones. These can take a long time to form but can be associated with steal syndromes due to decreased perfusion to the distal extremity, venous incompetence, varicosities, and eventually stenoses due to unreasonably high flow, and even high-output heart failure.

Increased AFP can be due to

1) neural tube defects

2) abdominal wall defects

3) multiple gestations

Do an ultrasound to r/o (3)

We can only put the laboratory tests into context if we have an accurate gestational age. Since her LMP is unreliable (totally unknown), we need an ultrasound to date her pregnancy. The most common cause of an abnormal MSAFP is wrong dates.

TTP always seems like too many disparate symptoms but just remember the pentad: thrombocytopenia, microangiopathic hemolytic anemia, neurologic symptoms, renal failure, and fever. If the symptoms list seems super long, keep TTP in mind.

Classic factitious disorder Q

Health care worker (nurse) with dramatic hypoglycemia and some signs of mental illness (+ risky drinking, + stress, + young woman)

To check for exogenous insulin, look for C-peptide.

C-peptide is a cleavage byproduct of endogenous insulin production. If high insulin and normal or low C-peptide --> exogenous insulin = factitious disorder

Kind of a Step 1 question

Working up serious hypoglycemia involves measurement of both insulin and C-peptide (the cleaved by-product of endogenous proinsulin) to assess for hyperinsulinemia and distinguish endogenous (e.g. insulinoma) from exogenous (e.g. Munchausen’s) causes. “Nurse” is a common Munchausen tip-off (someone with the know-how and skills to pull it off well).

Via urinalysis and renal ultrasound, we’ve excluded serious/treatable causes of renal hypertension including Conn’s disease (hyperaldosteronism) and renal artery stenosis such as due to fibromuscular dysplasia. That leaves her obesity.

Vasculitides like Wegener’s granulomatosis, microscopic polyangiitis, and others can cause poly-symptom disease and glomerulonephritis (hence the hematuria and proteinuria). Positive ANCA, (either P-ANCA or C-ANCA depending on the variant) is the key laboratory finding.

Infant with persistent diarrhea, vomiting after feeds, weight loss, hepatosplenomegaly, jaundice and +reducing substances

Classic Galactosemia

From step 1: Galactokinase deficiency, phosphate trapping

These questions can be a true pain of biochemistry on the Step 1 or relatively straightforward depending on how well you know it. This patient has classical Galactosemia, caused by a deficiency in galactose-1-P uridyl transferase deficiency, the enzyme that converts galactose and lactose to glucose. Intolerance to dairy, hepatomegaly/liver disease/jaundice with hypoglycemia due to decreased gluconeogenesis, and reducing substances in urine are classic. Listlessness and lethargy ensue with mental retardation and eventually death if untreated. Cataracts are also common. If you didn’t get to galactosemia (or thought it was Von Gierke’s disease, which isn’t all that unreasonable), the answer is still A. By process of elimination, given the serum hypoglycemia but no urine glucose, the issue is the inability to make glucose from stores (not to absorb it).

Pleuritic chest pain and hypoxia with a normal chest x-ray should lead you to pulmonary embolism. There’s usually enough total lung and blood flow, but it’s the VQ mismatch that’s the issue.

Endometriosis is a common cause of infertility and is associated with chronic pelvic/abdominal pain and excruciating periods. Gold standard for diagnosis is laparoscopy (visualization of “chocolate cysts”).

The primary mechanism by which beta-blockers reduce angina is via decreased contractility, which reduces the oxygen demand of the myocardium (which has a constrained supply due to coronary artery disease). Lowering heart rate also helps, but that isn’t one of your choices.

Confusion and tremulousness a few days after an unexpected hospital admission on the USMLE means alcohol withdrawal (unanticipated detox).

Hashimoto thyroiditis

• early stage transient hyperthyroidism
• progresses to subclinical hypothyroidism
• then finally overt hypothyroidism

This patient has clear signs of hypothyroidism (dry skin, brittle hair, periph edema, temp intolerance, weight gain, bradycardia, lethargy, etc)

Most common cause of noniatrogenic hypothyroidism

The most common cause of hypothyroidism in developed countries is Hashimoto’s thyroiditis. In developing countries, it’s iodine deficiency.

Thrombocytopenia without antiplatelet antibodies or splenomegaly implies a platelet production problem (e.g. myelofibrosis). History of radiation therapy is a risk factor. The only way to know what’s happening at the factory is a bone marrow biopsy.

The radiograph is showing complete collapse of the left lung (2/2 mucous plugging) with resultant severe ipsilateral mediastinal shift. An acute shift can have the same effect as any other “tension”-type process, causing impaired venous return to the heart and decreased cardiac output via the Starling mechanism.

This patient has chronic (6 weeks) symptomatic hypotension while not coincidentally on three BP meds: a diuretic, a beta blocker, and an ACE inhibitor. The most likely explanation and easiest/fastest intervention is to reduce her polypharmacy.

He's probably having an ischemic stroke

But you can't be sure!

First step is non-con CT

Other wrong answers:

• Don't do an LP until you know there is no bleed; they could herniate!

• EEG has no place in acute stroke w/u

• Carotid duplex US helps find source of stroke, but doesn't help in acute w/u

• angiography maybe later

The first imaging test in acute stroke is a noncontrast CT scan of the head. At 12 hours out, it may show ischemic strokes, but more importantly, it will diagnose hemorrhagic strokes, for which reperfusion and antiplatelet therapies are contraindicated.

A P T M

There's a physiologic splitting on inspiration in the pulmonic area

It's not pulmonic stenosis because there's no associated murmur. You would expect crescendo-decrescendo murmur, increase on inspiration, systolic ejection click, widened split of S2. All we hear is split S2.

Let the poor kid BALL

This is Paget-Schroetter disease

An upper extremity thrombosis triggered by extreme activity.

He's a fit young jackhammerer just trying to do his jackhammer thing

Atopic dermatitis (eczema) is the “itch that rashes.” It’s one leg of the allergic triad: asthma, allergic rhinitis, and atopic dermatitis. Treatment is with topical steroids and rigorous emollient therapy.

This patient has urge incontinence, which is commonly caused by detrusor instability (and can be treated with anticholinergics like oxybutynin). This is opposed to stress incontinence, the other most common type, which is worsened by abdominal pressure/coughing/laughing/etc and can be caused by pelvic floor prolapse secondary to multiple childbirths etc. Neurogenic bladder can cause overflow incontinence.

Multiple lytic bone lesions equals multiple myeloma. Blastic/sclerotic lesions should make you think of metastatic prostate cancer (in men) and breast cancer (in women).

Patients who have the capacity to make medical decisions are allowed to refuse life-saving medical treatment. You should offer it but accept her refusal.

Young woman with long history of crampy abd pain, diarrhea, + relieved by defection, without red flag symptoms.

It's IBS

Tricyclics can be used for IBS; they help with pain and can help with diarrhea

Could also have used antispasmodics like dicyclomine and hyoscyamine for the pain

For diarrhea, can also use loperamide or other antidiarrheals

For constipation type IBS try fiber, osmotic laxatives, lubiprostone

IBS is a “functional” G.I. problem, which means that it is a diagnosis of exclusion (must rule out IBD, Celiac, etc). You may have enjoyed its recent popular appearance on television as a disturbing anthropomorphized walking bowel. Common symptoms include diarrhea, constipation, pain relieved by defecation, and flatulence, often subject to a degree of emotional valence. As such, like headaches, IBS symptoms can be improved by TCA therapy, such as nortriptyline.

While you may have initially been thinking of alcohol withdrawal, the case presents you with signs/symptoms of decompensated cirrhosis including hepatic encephalopathy from hyperammonemia (AMS, asterixis). Treatment is oral lactulose, which helps clear ammonia via the power of horrible diarrhea.