A 48-year-old woman comes to the emergency department complaining of a severe, throbbing h… — USMLE Step 2 CK

A 48-year-old woman comes to the emergency department complaining of a severe, throbbing headache, blurred vision, and mild shortness of breath that began $2$ days ago. She has a $4$ -year history of diffuse cutaneous systemic sclerosis. Her home medications include mycophenolate mofetil and omeprazole. In the emergency department, her blood pressure is $220/125$ mmHg, pulse is $98$ /min, and respiratory rate is $18$ /min. Physical examination reveals tight, thickened skin over her face, trunk, and proximal extremities. Funduscopic examination shows bilateral papilledema and flame-shaped hemorrhages. Lung auscultation reveals bibasilar crackles.

Laboratory evaluation:
Hemoglobin: $8.9$ g/dL
Platelets: $95,000$ /mm $^3$
Creatinine: $2.7$ mg/dL (baseline $0.8$ mg/dL)
Peripheral blood smear: 3-4 schistocytes per high-power field

Which of the following is the most appropriate initial pharmacological treatment for this patient's current condition?

Oral captoprilCevap
B
Intravenous labetalol
C
Intravenous methylprednisolone
D
Plasma exchange
E
Intravenous sodium nitroprusside

Cevap

Oral captopril

The patient's presentation of malignant hypertension, acute kidney injury, and microangiopathic hemolytic anemia (schistocytes, thrombocytopenia) in the setting of diffuse cutaneous systemic sclerosis is classic for scleroderma renal crisis (SRC). SRC is caused by marked intimal proliferation of renal arterioles leading to decreased renal perfusion, which triggers massive activation of the renin-angiotensin-aldosterone system (RAAS). This creates a vicious cycle of severe hypertension and further renal vasoconstriction. The cornerstone of management is rapid RAAS blockade using a short-acting ACE inhibitor, specifically oral captopril. Importantly, ACE inhibitors must be initiated immediately, even in the setting of acute kidney injury and an elevated creatinine, as they uniquely reverse the underlying pathophysiologic mechanism and offer the best chance for renal recovery.

Adım Adım Çözüm

Identify the primary diagnosis based on the clinical presentation and history.

The patient has systemic sclerosis and presents with malignant hypertension, acute kidney injury, and microangiopathic hemolytic anemia (MAHA), establishing the diagnosis of scleroderma renal crisis (SRC).

Recognizing the complication is essential to selecting the targeted therapy, as SRC management differs from generic hypertensive emergencies.

Determine the underlying pathophysiology driving the crisis.

SRC is driven by massive activation of the renin-angiotensin-aldosterone system (RAAS) causing severe renal vasoconstriction.

Understanding the mechanism dictates that the therapy must directly inhibit this pathway.

Select the appropriate pharmacotherapy to counteract the mechanism.

An angiotensin-converting enzyme (ACE) inhibitor, specifically captopril, is selected.

ACE inhibitors are uniquely effective in reversing the RAAS hyperactivation and are indicated even in the presence of acute kidney injury.

Anahtar Kavram

Scleroderma renal crisis presents with acute oliguric renal failure and malignant hypertension, and the first-line, life-saving treatment is immediate administration of an ACE inhibitor (captopril) regardless of the elevated serum creatinine.

Soru

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Konular

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