Table 4 Classification criteria for scleroderma renal crisis

a. HBP ≥ 140/90 mmHg (or increase of systolic BP ≥ 30 mmHg or diastolic BP ≥ 20 mmHg) obtained on two different measurements with a minimum separation of 5 min, with no explanation other than SSc

b. Acute renal injury, with no explanation other than SSc AKI according to the KDIGO classification: more than 50% increase of serum creatinine from the reference value within the preceding 7 days or an absolute increase of 26.5 µmol/l (≥ 0.3 mg/dl) in 48 h

c. Thrombotic microangiopathy

 New or aggravated anemia without other explanation

 Schizocytes

 Thrombopenia ≤ 100,000/mm³ confirmed on a smear

 Signs of hemolysis: elevated LDH, low haptoglobin, increased reticulocytes

 Negative antiglobulin test

d. Target organ dysfunction

 Hypertensive retinopathy

 Hypertensive encephalopathy

 Pulmonary edema

 Acute pericarditis

e. Anomalies suggestive of renal biopsy (fibrinous thrombi, fibrinoid necrosis, glomerular collapse, onion bulb proliferation in pre-glomerular arterioles and arch arteries)

1. Increase of creatinine level > 50% of baseline value

 OR creatinine level ≥ 120% of upper normal laboratory reference value

 AND

2. At least one of the following five criteria:

 a. Proteinuria ≥ 2+ by strip

 b. Hematuria ≥ 2+ by strip or ≥ 10 RBC per field

 c. Thrombopenia < 100,000/mm³

 d. Hemolysis defined by anemia not linked to another cause with:

  (1) Schizocytes or other RBC fragments found on blood smear

  (2) Increase in reticulocyte level

 e. Renal biopsy showing a typical appearance of scleroderma renal crisis (fibrinous thrombi, fibrinoid necrosis, glomerular collapse, onion bulb proliferation in pre-glomerular arterioles and arch arteries)