Illness in very-long chain acyl-coA dehydrogenase deficiency (VLCAD) covers a wide spectrum, ranging from minor decompensation in mild VLCAD to cardiomyopathy in severe VLCAD. This guideline includes recommendations for treating symptomatic individuals as well as prophylaxis to prevent illness and inpatient care for those with moderate or severe VLCAD who are prone to developing cardiomyopathy and/or rhabdomyolysis. Most of the evidence about illness management in VLCAD comes from case studies of individuals presenting with cardiomyopathy, rhabdomyolysis, and/or hypoglycemia. There is no published literature on managing illness in mild VLCAD.

For individuals with cardiomyopathy (with or without rhabdomyolysis or hypoglycemia), nutrition intervention often includes supplemental medium chain triglycerides (MCT-enriched formula in infancy or MCT-based supplements) and restricting intake of long-chain fat (LCF). Diet modification is almost always recommended with other interventions (fluids, glucose, L-carnitine, fasting restrictions), making it difficult to assess the impact of any single intervention. A low-fat diet with MCT supplementation or MCT-containing formula has been shown to reverse cardiomyopathy.

The effect of a MCT-supplemented, low fat diet to prevent or reduce episodes of rhabdomyolysis is inconclusive. In some reports of individuals presenting with both cardiomyopathy and rhabdomyolysis, the cardiomyopathy improved with diet modification, but rhabdomyolysis persisted. In other case reports of individuals with late-onset rhabdomyolysis, providing extra carbohydrate (without MCT) improved symptoms.

Home precautions to prevent symptoms in VLCAD include avoiding long periods of fasting through frequent and/or overnight feedings. Use of uncooked cornstarch (UCCS) has been reported in the literature, but is infrequently used among Delphi survey respondents. Avoidance of extreme and prolonged physical exercise appears to be helpful in preventing rhabdomyolysis. Clear guidelines regarding the recommended duration and intensity of exercise are lacking and the emphasis is on providing sufficient energy to support exercise, as tolerated.

In acute illness, fasting duration is reduced as compared to when well. Moreover, early institution of IV dextrose and adequate hydration helps to prevent a metabolic or myopathic crisis and may resolve or improve cardiomyopathy and rhabdomyolysis. Use of IV lipids is contraindicated during an acute illness.

Caregivers should be provided with, and utilize, an emergency protocol in times-of or leading-up-to a symptomatic presentation. Emergency intervention should not wait for detection of hypoglycemia, which is a late finding in VLCAD. For the same reason, home monitoring of blood glucose for presence of hypoglycemia is not recommended.

The use of carnitine and other medications/supplements during illness is discussed in Recommendation 3.