Medical Knowledge 7 Flashcards

A 58-year-old male with chronic kidney disease (eGFR 22 mL/min/1.73m²) presents with a serum potassium of 6.8 mEq/L and peaked T-waves on ECG. Which intervention takes priority BEFORE administering sodium bicarbonate or insulin-glucose?

Answer: Intravenous calcium gluconate

Calcium gluconate is the first-line intervention for severe hyperkalemia with ECG changes because it stabilizes the cardiac membrane potential within 1–3 minutes, preventing fatal arrhythmias. It does not lower serum potassium but protects the heart while subsequent interventions (insulin-glucose, bicarbonate, dialysis) reduce potassium levels. Kayexalate acts over hours, furosemide is ineffective in advanced CKD, and salbutamol is an adjunct, not the cardiac membrane stabilizer.

A 34-year-old woman at 28 weeks gestation develops sudden-onset severe headache, visual scotomata, and a blood pressure of 158/108 mmHg. Urinalysis shows 3+ proteinuria. Her platelet count is 88,000/µL, ALT is 210 U/L, and LDH is 890 U/L. Which diagnosis best fits this clinical picture?

Answer: HELLP syndrome

HELLP syndrome is characterized by Hemolysis (elevated LDH), Elevated Liver enzymes (ALT 210 U/L), and Low Platelets (<100,000/µL). Although this patient also meets criteria for severe pre-eclampsia, the triad of thrombocytopenia, transaminase elevation, and hemolysis markers classifies this as HELLP, which carries a distinct management pathway and worse prognosis. Gestational hypertension lacks proteinuria or end-organ damage. Acute fatty liver of pregnancy typically presents with hypoglycemia, coagulopathy, and microvesicular steatosis on biopsy.

A physician prescribes warfarin for a patient with atrial fibrillation. Two weeks later, the patient's INR is 6.8 with no signs of active bleeding. Which is the MOST appropriate next step?

Answer: Hold warfarin and administer oral vitamin K 1–2.5 mg

For supratherapeutic INR (5–10) without active or serious bleeding, guidelines recommend holding warfarin and giving low-dose oral vitamin K (1–2.5 mg) to lower INR over 24–48 hours while minimizing the risk of over-correction that would cause a rebound hypercoagulable state. IV vitamin K 10 mg is reserved for life-threatening bleeding with or without FFP. Holding warfarin alone is used for INR 4.5–10 without high bleeding risk. FFP is reserved for major hemorrhage or urgent reversal.

A 45-year-old HIV-positive patient (CD4 count 55 cells/µL, not on ART) presents with a week of progressively worsening headache, low-grade fever, and neck stiffness. CSF analysis reveals: opening pressure 320 mmHg, WBC 8 cells/µL (lymphocyte-predominant), glucose 35 mg/dL (serum 90 mg/dL), protein 120 mg/dL, and India ink stain positive. What is the FIRST-LINE induction treatment?

Answer: Amphotericin B deoxycholate + flucytosine for 2 weeks

Cryptococcal meningitis (confirmed by positive India ink) in HIV patients is treated with amphotericin B deoxycholate (0.7–1 mg/kg/day) plus flucytosine (100 mg/kg/day) for 2 weeks as induction, followed by consolidation with fluconazole. This combination is superior to fluconazole monotherapy in fungal clearance and survival. Liposomal amphotericin B monotherapy is less efficacious than the combination. Voriconazole and caspofungin have no established role for cryptococcal meningitis. Additionally, the elevated opening pressure requires therapeutic lumbar punctures.

During a routine health check, a 52-year-old asymptomatic male is found to have a serum calcium of 11.4 mg/dL, PTH of 92 pg/mL (elevated), phosphate of 2.1 mg/dL, and 24-hour urinary calcium of 380 mg. Which condition is the MOST likely diagnosis, and what is the initial surgical threshold criterion met here?

Answer: Primary hyperparathyroidism; 24-hour urinary calcium >350 mg meets the nephrolithiasis-risk surgical criterion

The combination of hypercalcemia, elevated PTH, hypophosphatemia, and hypercalciuria is diagnostic of primary hyperparathyroidism (PHPT). According to the 4th International Workshop guidelines for asymptomatic PHPT, indications for parathyroidectomy include 24-hour urinary calcium >400 mg/day OR a calcium/creatinine clearance ratio >0.01 as nephrolithiasis risk criteria. Some guidelines use >350 mg as a threshold trigger for surgical consideration in combination with other factors. Familial hypocalciuric hypercalcemia (FHH) causes low urinary calcium excretion (ratio <0.01) — the opposite finding. Secondary hyperparathyroidism from vitamin D deficiency does not cause hypercalcemia.

A 67-year-old male with a 40 pack-year smoking history presents with ptosis, miosis, and anhidrosis of the right side of his face. Chest X-ray shows a right apical mass. Which anatomical structure is most likely compressed by this mass, and what is the eponymous name of this syndrome?

Answer: Right sympathetic chain at the stellate ganglion level; causing Horner syndrome in the context of a Pancoast tumor

The triad of ptosis (drooping eyelid), miosis (constricted pupil), and anhidrosis (absence of sweating) is Horner syndrome, caused by interruption of the oculosympathetic pathway. An apical lung mass (Pancoast tumor) compresses the stellate ganglion and the cervical sympathetic chain at the thoracic inlet, producing ipsilateral Horner syndrome. The phrenic nerve injury causes hemidiaphragm elevation, not Horner syndrome. SVC compression causes venous congestion. The recurrent laryngeal nerve (left side, notably) wraps around the aortic arch and causes hoarseness, not Horner syndrome.