A 38-year-old woman comes to the emergency department for evaluation of altered mental status that began five hours ago. She is accompanied by her husband. Past medical history is notable for asthma and diffuse scleroderma. On arrival, her temperature is 37.6°C (99.7°F) and blood pressure is 183/121 mmHg. On physical examination, the patient is oriented to self but neither time nor place. Diffuse thickening of the skin is observed, and contractures are present in the bilateral fingers. Laboratory testing is obtained, and results are as follows:
| Laboratory value | Result |
| Hemoglobin | 10.7 g/dL |
| Leukocyte Count | 7,300/mm3 |
| Platelet Count | 80,000/mm3 |
| Blood Urea Nitrogen | 35 mg/dL |
| Creatinine, Serum | 2.0 mg/dL |
Which of the following is the next best step in the management of this patient’s condition?
A. Initiation of propranolol therapy
B. Initiation of captopril therapy
C. Initiation of methotrexate therapy
D. Long-term dialysis
E. Initiation of prednisone therapy
Scroll down for the correct answer!
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The correct answer to today’s USMLE® Step 2 CK Question is…
B. Initiation of captopril therapy
Before we get to the Main Explanation, let’s see why the answer wasn’t A, C, D or E. Skip to the bottom if you want to see the correct answer right away!
Incorrect answer explanations
Today’s incorrect answers are…
A. Initiation of propranolol therapy
Incorrect: This patient’s altered mental status, hypertension and elevated blood urea nitrogen and creatinine levels, in the setting of a known history of diffuse scleroderma, raise concern for scleroderma renal crisis. However, treatment with beta-blockers is generally contraindicated, since they can cause vasoconstriction, thereby increasing the risk of developing digital ulcers in patients with scleroderma.
C. Initiation of methotrexate therapy
Incorrect: Methotrexate can be used to treat skin thickening and tightening in patients with scleroderma. This patient’s thickened skin and finger contractures are consistent with her known history of scleroderma. However, her hypertension and elevated blood urea nitrogen and creatinine levels raise concern for scleroderma renal crisis, for which methotrexate is not useful.
D. Long-term dialysis
Incorrect: Short-term dialysis is used in nearly 50% of patients with scleroderma renal crisis. However, once the patient’s condition has improved and the body is able to regulate blood pressure, dialysis can be discontinued. Long-term dialysis may be indicated in patients who develop end-stage renal disease secondary to scleroderma renal crisis. Currently, not enough is known about this patient’s prognosis, and therefore, initiating long-term dialysis would be premature.
E. Initiation of prednisone therapy
Incorrect: Corticosteroids are used in the treatment of many autoimmune and inflammatory conditions. However, they are generally contraindicated in the management of scleroderma renal crisis. This is because glucocorticoids may play a role in the occurrence of scleroderma renal crisis, though the exact mechanism remains unclear.
Main Explanation
This patient is having a scleroderma renal crisis, which is characterized by severe hypertension and acute renal failure. Over 90% of patients with scleroderma renal crisis have blood pressures exceeding 150/90 mmHg. Renal failure can present with elevated blood urea nitrogen and creatinine levels. In addition, patients can present with hypertensive encephalopathy, heart failure, and arrhythmias.
The pathophysiology of scleroderma renal crisis is unclear; however, it is believed that the renin-angiotensin-aldosterone system (RAAS) plays an important role. Scleroderma is known to cause damage to small arteries within the kidneys, which subsequently undergo hypertrophy, resulting in relative ischemia. In severe cases, damage to the renal blood vessels can trigger thrombosis, occluding the glomerular capillaries. This causes rapid deterioration in renal function, resulting in scleroderma renal crisis. Of note, the thrombosis can lead to a low platelet count on laboratory testing, as well as the presence of schistocytes on peripheral blood smear.
Angiotensin-converting (ACE) inhibitors are the first-line treatment for scleroderma renal crisis. Dialysis can be used in an acute setting in patients with significant kidney injury; however, long-term dialysis is indicated only in patients who develop end-stage renal disease as a result of the injury.
Major Takeaway
Scleroderma renal crisis is characterized by severe hypertension and acute renal failure. It can present with hypertensive encephalopathy, heart failure, and arrhythmias. Laboratory testing will reveal an elevated blood urea nitrogen, elevated creatinine, and low platelet count. ACE-inhibitors are the first-line treatment option.
References
Mouthon, L., Bussone, G., Berezne, A., Noel, L., Guillevin, L. (2020) Scleroderma renal crisis. The Journal of Rheumatology. 41(6), 1040-1046. Doi: 10.3899/jrheum.131210.
Vidya, P.N., Finnigan, N.A. (2020) “Scleroderma and renal crisis”. StatPearls [Internet]. Web Address: https://www.ncbi.nlm.nih.gov/books/NBK482424/.
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