17 December 2025
: Case report 
COVID-19-Associated MDA5-Mediated Necrotizing Myositis
Challenging differential diagnosis, Unusual or unexpected effect of treatment, Rare disease
Sarah Steadman ABCDEF 1, Amit Sikder ABCDEF 2, Harsh R. Desai
ABCDEF 3*, Bradley Collins BE 4, Tiffany Baker BDE 5, Julie Worthington ABCDEF 6
DOI: 10.12659/AJCR.949788
Am J Case Rep 2025; 26:e949788
Table 1 Biochemical laboratory test values during hospital admission.
| Laboratory test | Admission | Day 3 | Discharge (Day 8) | Reference range |
|---|---|---|---|---|
| White blood count | 9.6 k/mm | 5.0–11.0 | ||
| Platelet count | 269 k/mm | 135–350 | ||
| Hemoglobin | 16.5 g/dL | 13.5–16.5 | ||
| Creatinine | 1.0 mg/dL | 0.7 mg/dL | 0.9 mg/dL | 0.7–1.2 |
| Blood urea nitrogen | 13 mg/dL | 9 mg/dL | 21 mg/dL | 6–20 |
| Potassium | 3.8 mEq/L | 4.3 mEq/L | 3.7 mEq/L | 3.6–5.1 |
| Calcium | 8.8 mg/dL | 8.8 mg/dL | 8.2 mg/dL | 8.9–10.3 |
| Albumin | 4.0 g/dL | 3.4 g/dL | 3.0 g/dL | 3.4–4.8 |
| Total protein | 7.4 g/dL | 7.0 g/dL | 6.1–8.0 | |
| Bicarbonate | 25 mEq/L | 25 mEq/L | 25 mEq/L | 22–32 |
| Aspartate transaminase (AST) | <35 | |||
| Alanine aminotransferase (ALT) | 10–63 | |||
| Alkaline phosphatase (ALP) | 61 U/L | 56 U/L | 57 U/L U/L | 32–101 |
| Total bilirubin | 0.9 ng/mL | 0.9 ng/mL | 0.5 ng/mL | <1.0 |
| Ferritin | 252.1 ng/mL | 24.0–336.0 | ||
| Erythrocyte sedimentation rate | 6 mm/h | 0–15 | ||
| C-reactive protein | 1.10 mg/dL | 0.00–1.0 | ||
| Lactic acid | 1.9 mEq/L | 0.5–2.0 | ||
| Creatine kinase | 49–397 | |||
| Troponin | 0.03 ng/mL | <0.04 | ||
| Myoglobin | 28–72 | |||
| D-dimer | 0–499 | |||
| Aldolase | <1.2 U/L | 3.3–10.3 | ||
| Lactate dehydrogenase | 98–192 | |||
| Thyroid stimulating hormone | 1.32 U/mL | 0.34–5.60 | ||
| Cholesterol | 157 mg/dL | <200 | ||
| LDL cholesterol | 0–100 | |||
| HDL cholesterol | 37 mg/dL | >59 | ||
| Triglycerides | 53 mg/dL | <150 | ||
| Hemoglobin A1c | 5.2% | 4.8–6.0 | ||