Exertional rhabdomyolysis, profound lactic acidosis, and acute kidney injury in a young boy: Questions

Excerpt

A 9-year-old boy presented with shortness of breath, palpitation, and decreased urine amount 1 day after 30-m three-legged race. He was born to healthy non-consanguineous parents with normal growth and development. He had no history of recent viral infection, medication, or known endocrine disorders, except for exertional intolerance. His blood pressure was 100/60 mmHg, heart rate 150 beats/min, respiratory rate 36/min, and body temperature 36.6 °C. His consciousness was drowsy, skin turgor reduced, and lower limb tender and swollen. The remainder of physical examination was non-revealing. Blood laboratory abnormalities included remarkable metabolic acidosis (pH 7.05, anion gap 35 mmol/l, Na⁺ 144 mmol/l, K⁺ 3.5 mmol/l, Cl⁻ 104 mmol/l, HCO₃ ⁻ 5.0 mmol/l), lactate 280 (10–20 mg/dl), serum creatine kinase 5,100 (20–180 IU/l), and creatinine 2.3 mg/dl. Other laboratory studies showed blood urea nitrogen 33 mg/dl, total Ca⁺⁺ 9.5 mg/dl, iP 4.0 mg/dl, hemoglobin 12.8 g/dl, glucose 152 mg/dl, ketone 0.7 mmol/l, osmolar gap 10 mOsm/l, ammonia 85 mg/l, and uric acid 7.0 mg/dl. Hormone profiles including thyroid, adrenal, and parathyroid function were normal. Due to acute kidney injury with oliguria, he received a 10-day course of continuous venovenous hemofiltration. Although his renal function completely recovered 2 weeks later, hyperlactemia (lactate 35 mg/dl) and hyperCKemia (creatine kinase 610 IU/l) were still persistent. Ischemic forearm exercise test (IFET) for glycolysis/glycogenolysis metabolic disorders and purine metabolic disorders and oral glucose lactate stimulation test (OGLST) for mitochondrial diseases were performed. The results are shown in Table 1. …