A 42-year-old woman arrives at the emergency department reporting a severe, throbbing headache and blurred vision that began this morning. She also notes new-onset shortness of breath over the past two days. Her medical history includes diffuse cutaneous systemic sclerosis, which was diagnosed four years ago. She currently takes mycophenolate mofetil. Vital signs show a blood pressure of 230/125 mmHg, a heart rate of 110/min, and a respiratory rate of 22/min. Physical examination reveals thickened, tight skin over the face and proximal extremities, as well as bilateral basilar crackles on lung auscultation. Laboratory studies show:
| Test | Result |
|---|---|
| Hemoglobin | 8.8 g/dL |
| Platelets | 82,000/mm |
| Creatinine | 3.1 mg/dL (baseline 0.8 mg/dL) |
| Peripheral blood smear | Numerous schistocytes |
| Urinalysis | 1+ proteinuria, no red blood cell casts |
Which of the following is the most appropriate next step in the management of this patient?
- Oral captoprilAnswer
- BLabetalol infusion
- CMethylprednisolone pulse therapy
- DTherapeutic plasma exchange
- ECyclophosphamide therapy
Answer
Oral captopril
The correct answer is oral captopril. This patient's presentation of malignant hypertension, acute kidney injury, and microangiopathic hemolytic anemia in the setting of diffuse cutaneous systemic sclerosis is highly characteristic of scleroderma renal crisis (SRC). The primary pathogenesis of SRC involves endothelial injury leading to intimal proliferation of the renal arteries, which causes decreased renal perfusion and a massive release of renin. This severe hyperactivation of the renin-angiotensin-aldosterone system (RAAS) necessitates the prompt initiation of an ACE inhibitor. Short-acting agents like captopril are considered the drug of choice because they can be rapidly titrated to gain control of blood pressure and halt progressive renal damage.
Step-by-Step Solution
Key Concept
Diagnosis and management of Scleroderma Renal Crisis
Estimated Time:1m 30s