Hypertensive emergency · KIMS Secunderabad
Scleroderma Renal Crisis — A Hypertensive Emergency in Systemic Sclerosis
Scleroderma renal crisis (SRC) is one of the most serious complications of systemic sclerosis (SSc) — a rare but potentially fatal rapid deterioration of kidney function, occurring in approximately 5 to 10% of SSc patients. It is characterised by sudden onset of severe hypertension (blood pressure typically above 150 to 170 systolic, often above 200 mmHg), rapidly rising serum creatinine (AKI), and features of thrombotic microangiopathy — microangiopathic haemolytic anaemia and thrombocytopenia in approximately 50% of cases. Before the introduction of ACE inhibitors in the 1980s, SRC was uniformly fatal within weeks. ACE inhibitors — specifically captopril — are the life-saving treatment for SRC, and their early and aggressive use has transformed SRC from a universally fatal complication to one from which many patients can recover kidney function.
The mechanism of SRC: systemic sclerosis causes progressive intimal thickening and luminal narrowing of the renal interlobular and arcuate arteries from proliferative endarteritis. When renal blood flow is critically reduced — triggered by cold exposure, volume depletion, or — importantly — corticosteroid use — the ischaemic kidney releases massive quantities of renin, causing a severe renin-driven hypertension that further reduces renal perfusion (a vicious cycle). ACE inhibitors break this cycle by blocking angiotensin II generation, reducing renal afferent vasoconstriction and renin-driven hypertension.
Risk factors for SRC
Clinical and serological predictors of scleroderma renal crisis
Early diffuse cutaneous SSc (dcSSc — skin involvement proximal to elbows and knees) within the first 4 years of diagnosis — the highest-risk period.
Rapidly progressive skin disease — rapidly worsening skin thickening predicts SRC risk.
Anti-RNA polymerase III antibody — the most specific serological predictor of SRC. Approximately 20 to 25% of anti-RNAP III-positive SSc patients develop SRC.
Corticosteroid use — high-dose steroids (prednisolone above 15mg/day) in SSc patients are associated with triggering SRC, likely from volume effects and further vasoconstriction. SSc patients on steroids must have blood pressure monitored closely.
New anaemia — sudden unexplained anaemia in a SSc patient may represent early TMA from SRC.
Clinical features — the diagnostic triad
Sudden severe hypertension
The most prominent feature. Typically above 150 to 170 mmHg systolic, often with new-onset diastolic hypertension above 90 mmHg, in a patient who was previously normotensive or only mildly hypertensive.
Rapidly rising creatinine
AKI developing over days to weeks. Oliguria or anuria in severe cases.
TMA features
Haemolytic anaemia (low haemoglobin, raised LDH, low haptoglobin), thrombocytopenia, and schistocytes on blood film — in approximately 50% of SRC cases.
Hyperreninaemia
Markedly elevated plasma renin activity confirms the renin-driven mechanism.
Absence of significant proteinuria
SRC does not cause glomerulonephritis. Proteinuria is typically minimal (below 1 g/day) despite severe AKI — this distinguishes SRC from other forms of lupus or vasculitis nephritis.
Hypertensive retinopathy or encephalopathy
In severe SRC with blood pressure above 200/120 mmHg.
Treatment — ACE inhibitors are the cornerstone
Captopril
The treatment of choice for acute SRC. Short-acting ACE inhibitor given orally or via NG tube. Starting dose 6.25 to 12.5mg every 8 hours, rapidly titrated upward to maximum tolerated dose to achieve blood pressure below 120/80 mmHg within 72 hours. Captopril is preferred over long-acting ACE inhibitors (enalapril, ramipril) because its short duration allows rapid dose adjustment if blood pressure drops too precipitously. Blood pressure is reduced gradually — too rapid a drop in BP in a patient with renal artery disease reduces GFR further.
Aggressive titration
Target BP below 120/80 mmHg within 72 hours. The early and aggressive use of ACE inhibitors is the defining characteristic of SRC management. Historical data clearly shows that delay in starting ACE inhibitors dramatically worsens outcomes — every day of uncontrolled hypertension-driven renal ischaemia adds irreversible nephron loss.
CRRT for AKI
CRRT for fluid overload, hyperkalaemia, or severe uraemia while ACE inhibitors control the hypertension and the renin cycle. At KIMS, CRRT is continued for 3 to 6 months in SRC patients on dialysis while awaiting potential kidney function recovery — some patients recover enough renal function to discontinue dialysis months after the initial crisis, if ACE inhibitors are maintained throughout.
ACE inhibitors are not contraindicated in SRC despite the AKI
They are the treatment. Withholding ACE inhibitors in a patient with SSc and rapidly worsening hypertension because of fear of 'ACE inhibitor nephrotoxicity' is a dangerous error that will be fatal. The rising creatinine in SRC is from hypertension-driven ischaemia — ACE inhibitors break this cycle. Creatinine may temporarily worsen as blood pressure is controlled (from loss of the angiotensin II-driven hyperfiltration that was maintaining eGFR in the face of renal artery disease) before improving.
Book an Emergency Nephrology Assessment for Scleroderma Renal Crisis at KIMS
Frequently Asked Questions — Scleroderma Renal Crisis
Systemic sclerosis (SSc) — also called scleroderma — is a systemic autoimmune disease characterised by fibrosis (excess collagen deposition), vasculopathy (abnormal small vessel function), and immune activation. The skin becomes thickened and tight — the hallmark feature. The same fibrotic and vasculopathic processes affect internal organs: lungs (pulmonary fibrosis, pulmonary arterial hypertension), gastrointestinal tract (oesophageal dysmotility, malabsorption), heart, and kidneys. In the kidneys, SSc causes progressive narrowing and obliteration of the small renal arteries from intimal proliferation and subintimal fibrosis — reducing renal blood flow and predisposing to the massive renin release of scleroderma renal crisis when renal perfusion is critically reduced.
SRC is a renin-driven hypertensive crisis — the ischaemic kidney releases massive quantities of renin, which converts angiotensinogen to angiotensin I, then to angiotensin II (a powerful vasoconstrictor). Angiotensin II constricts the afferent arterioles further, reducing renal blood flow more, generating more renin — a catastrophic positive feedback cycle. ACE inhibitors block the conversion of angiotensin I to angiotensin II — breaking the cycle, reducing vasoconstriction, lowering blood pressure, and restoring renal perfusion. No other antihypertensive class breaks this renin cycle as effectively. ARBs can be used if ACE inhibitors are genuinely not tolerated, but ACE inhibitors are the preferred agents based on decades of evidence in SRC.
Yes — this is one of the most clinically important pharmacological triggers of SRC. High-dose corticosteroids (prednisolone above 15mg/day) used in SSc patients — often for pulmonary fibrosis, myositis, or arthritis — are associated with an increased risk of precipitating SRC, possibly through sodium and water retention, volume expansion, and vasoconstrictive effects on the renal microvasculature. All SSc patients receiving steroids should have blood pressure monitored at home every 1 to 2 days and report any sudden rise above 140/90 mmHg immediately. Steroids are not absolutely contraindicated in SSc, but the dose should be minimised and blood pressure vigilance maintained.
Yes — partial or complete recovery of kidney function is possible in SRC if ACE inhibitors are started early and maintained aggressively. Remarkably, some SRC patients who required dialysis at presentation recover enough kidney function to discontinue dialysis 3 to 18 months after the crisis, as long as ACE inhibitors are continued throughout the recovery period. The probability of recovery is higher with: earlier ACE inhibitor initiation, lower maximum creatinine at the time of SRC, shorter duration of uncontrolled hypertension before treatment, and absence of cortical necrosis (which indicates irreversible nephron loss). At KIMS, dialysis in SRC patients is maintained for 12 to 18 months before concluding that kidney recovery will not occur.
KIMS Secunderabad — Dr. Susmitha Chandragiri (women's nephrology, SSc nephrology), rapid ACE inhibitor titration protocol (captopril, starting 6.25mg and titrating to achieve BP below 120/80 within 72 hours), TMA blood film and LDH monitoring, plasma renin activity, CRRT for AKI with long-term dialysis support during potential renal recovery phase (12 to 18 months), anti-RNAP III antibody for SRC risk stratification. NABH and NABL accredited. Emergency line: 040-4488-5000.