Dr. Ira Shah
M.D, DNB, DCH(Gold Medalist), FCPS

Myoglobinuria is a condition caused by skeletal muscle injury and rhabdomyolysis releasing muscle contents into the circulation and is often associated with Acute Renal Failure.

The common conditions associated with rhabdomyolysis and Myoglobinuria are :-

1. Ischemic injury to the muscle:crush injury, compartment syndrome.
   
2. Infections (coxsackie, echo, influenza, measles etc).
   
3. Anaesthesia associated succinyl choline and
   
4. Congenital enzyme deficiencies.
   
   

Congenital enzyme deficiencies are the commonest causes of Idiopathic Myoglobinuria.

We would like to report a case of this rare presentation in a child and review the complications and management of these patients.

-3 years old female child came with fever since 10 days and altered sensorium since 1 day. There was no history of any volume loss and other history was not contributory. Patient was febrile and had severe hypotension. Patient was started on IV Antibiotics and required volume resuscitation and Adrenaline drip. CT Scan (brain) was normal. On second day of admission, patient was noticed to have tender and palpable calf muscles with red color urine. Patient’s S. Creatine Phosphokinase was 35,000 IU/L which decreased to 24,600 IU/L the next day and was 1468 IU/L on the third day. Urine cleared by second day. Urine examination showed myoglobinuria. Patient’s other renal parameters were normal. Patient required massive fluid resuscitation (250ml/kg) for shock. Patient gradually recovered sensorium and achieved hemodynamic stability by the fourth day. Blood culture, coagulation profiles were normal. Patient was diagnosed as a case of rhabdomyolysis with myoglobinuria and severe hypovolemia. Patient subsequently regained all her milestones.

Rhabdomyolysis is a rare clinical entity in a pediatric patient. There are very few documentated case reports of myoglobinuria. They usually present with muscle swelling, tenderness and firm consistency of calves and lower back with red urine. It is diagnosed by presence of myoglobin in urine and elevated S. Creatine Kinase. Its main complications are (a) Hypovolemia and shock due to influx of fluid into damaged muscles. (b) Electrolyte disturbances – hyperkalemia, hyperphosphatemia and hyperuricemia with metastatic calcifications. (c) Acute renal failure – Associated factors with development of renal failure are a peak S. CPK>16,000 IU/L, urine pH < 5 and arterial pH<7.33(3) (d) Compartment syndrome.

Management of myoglobinuria involves treatment of any reversible cause of myoglobinuria, aggressive volume resuscitation (as high as 250 – 300 ml/kg in 1st few hours), treatment of hyperkalemia with exchange resins, and treatment of ARF. Aim is to achieve a urine of flow more than 2ml/kg/hr with fluids and mannitol and Bicarbonate infusion to maintain urine pH>6. Dialysis may be required in 50-70% of patients.

This case presented with classical red urine and elevated S.CPK and tender palpable calf muscles with severe shock and no other cause of fluid loss.Patient was managed aggressively and patient had a neurologically good outcome.

Thus,myoglobinuria requires a very early aggressive management of etiological agent and its complications.It should be suspected in any case of severe unexplained shock ,viral infections and crush injuries.S.CPK is a good screening test . In any patient if cause of myoglobinuria is not known then muscle biopsy and specific enzyme assays should be done if facilities are available to detect the cause of Idiopathic myoglobinuria.