LCAD deficiency
Overview
A rare inherited genetic condition where the body is unable to convert certain fats to energy i.e. there is not enough of a certain enzyme (3-hydroxyacyl-coenzyme A dehydrogenase) which is needed to metabolize a type of fat called long-chain fatty acids. The build-up of these fatty acids in the body causes damage.
Symptoms
* Feeding difficulty * Lethargy * Lack of energy * Low blood sugar * Muscle weakness * Liver problems * Retina abnormalities * Muscle pain
Causes
* Exogenous insulin administration is the most common cause of hypoglycemia –Most commonly occurs in patients with known diabetes mellitus –May occur with inadequate food ingestion or excessive exercise after an insulin injection –May occur with delayed absorption of food (e.g., diabetic gastroparesis) –Rarely, may occur as part of attention seeking behavior (i.e., factitious) * Oral hypoglycemic medications (e.g., sulfonylurea) –This is especially common with severe liver disease, which prevents gluconeogenesis * Other medications (e.g., salicylates, sulfonamides, tetracyclines, warfarin, MAO inhibitors, phenothiazines) * Reactive hypoglycemia occurs 2–4 hours after meals, due to delayed and exaggerated insulin release (associated with a family history of type II diabetes) * Hypothyroidism * Malnutrition/fasting * Insulinoma/islet cell hyperplasia * Alcohol consumption * Sepsis * Renal failure * Sarcomas * Pituitary or adrenal insufficiency * Congenital hormone or enzyme defects * Severe hepatic dysfunction (e.g., hepatitis, hepatic toxins, hepatic necrosis)
Diagnosis
The finding of hypoglycemia on routine blood analysis requires nothing in an asymptomatic patient. If there is doubt, a repeat analysis should be done. If the patient is symptomatic, a 5-hr glucose tolerance test or hospitalization for repeated blood sugar during a 72-hr fast should be done. If these are negative, the patient most likely has functional hypoglycemia. Additional tests to order include a T 4 , plasma, cortisol, plasma growth hormone assay, plasma proinsulin, C-peptide, plasma insulin, CT scan of the abdomen, and a tolbutamide tolerance test. Obtain an endocrinology consult.
Treatment
* Glucose therapy (therapy goal is glucose >100 mg/dL) –Alert patients may be repleted with oral glucose (e.g., juice, glucose tablets) or IV D50 –Patients with altered consciousness require IV D50 solution –In children, use bolus of 25% dextrose –Frequently recheck blood glucose * Glucagon may be used to increase glucose release from the liver if unable to obtain IV access and the patient cannot tolerate oral glucose; less effective in alcoholic and malnourished patients * Octreotide may be used in cases of sulfonylurea-induced hypoglycemia to inhibit insulin release * Thiamine must be given with glucose in any suspected case of alcohol abuse or nutritional deficiency to avoid Wernicke's encephalopathy * Hydrocortisone should be administered if blood glucose remains persistently low to rule out adrenal insufficiency