Necrotizing vacuolar myopathy presenting with recurrent myoglobinuria

Area of Science:

• Neurology
• Pathology
• Nephrology

Background:

• Myoglobinuria is a condition characterized by the presence of myoglobin in urine.
• It can indicate underlying systemic, neurological, or primary muscle disorders.
• Diagnosing the cause of myoglobinuria is crucial for effective management and preventing complications.

Observation:

• A 23-year-old male presented with recurrent episodes of myoglobinuria.
• Initial investigations ruled out common causes like toxin exposure, drug use, or seizures.
• Muscle biopsy revealed necrotizing vacuolar myopathy.

Findings:

• The observed intramuscular vacuoles in the muscle biopsy were atypical for known glycogen or lipid metabolism disorders.
• This suggested a novel or rare form of vacuolar myopathy.
• Recurrent myoglobinuria, when not linked to external factors, often points to intrinsic muscle pathology.

Implications:

• Early identification of myoglobinuria and its underlying cause, such as this rare myopathy, is vital.
• Prompt diagnosis and management can prevent acute kidney injury and chronic renal dysfunction.
• This case broadens the differential diagnosis for recurrent myoglobinuria, especially in the absence of typical triggers.