Medical Care
Hypoglycemia
Immediate diagnosis and treatment of hypoglycemia is essential. Children with seizures or prolonged recurrent episodes of hypoglycemia are more likely to experience brain damage. When the cause of hypoglycemia is unknown, start an intravenous line and collect 5-10 mL of blood in a heparinized tube.
When hypoglycemia is suspected, start treatment without waiting for the results of the blood or plasma glucose tests.
In neonates, administer intravenous (IV) 10% dextrose at 2.5 mL/kg as a rapid IV bolus followed by a continuous IV infusion of 3-5 mL/kg/h (5-8 mg glucose per kg/min).
In children, administer 50% dextrose diluted to 25% in water at an initial dose of 1 mL/kg IV followed by an IV infusion of 10% dextrose at 2-3 mL/kg/h (3-5 mg glucose per kg/min).
If any difficulty in establishing IV access occurs, intramuscularly administer glucagon at 0.03 mg/kg (not to exceed 1 mg). Glucagon therapy has a transient effect and must be followed by an intravenous dextrose infusion as above.
Glucocorticoid deficiency
Treatment for FGD includes the replacement of glucocorticoids in order to avoid not only adrenal crisis but to allow normal growth in these children. Glucocorticoid replacement is achieved with hydrocortisone (12-16 mg/m2/24h PO divided into 3 doses). An equivalent dose of prednisone or dexamethasone may be administered to adults and the occasional patient who has difficulty with compliance. However, the potential for growth suppression with either prednisone or dexamethasone is greater than hydrocortisone; and, therefore, these agents should be used with caution. Administer the lowest dosage necessary to prevent symptoms of adrenal failure in order to avoid suppression of growth.
The adequacy of a treatment regimen may be clinically judged by noting decreased hyperpigmentation, absence of weakness, and normalization of blood sugar values. Adequate glucocorticoid replacement should not cause any adverse effects. Suppression of adrenocorticotropic hormone (ACTH) levels in FGD can be very difficult and, therefore, should not be used as a goal for therapy.
Overtreatment may result in poor linear growth, hypertension, edema, euphoria, insomnia, headache, steroid-induced acne, hyperglycemia, Cushing syndrome, peptic ulcers, and cataract formation. [14]
Intercurrent illness or stress necessitates a readjustment of glucocorticoid dosage. For minor stress, such as a fever or upper respiratory tract infection, double or triple the glucocorticoid dosage until the illness has resolved. If the patient is ill with vomiting or diarrhea and cannot tolerate oral fluids and medication, hospitalization may be necessary. In individuals with severe stress, such as surgery or serious illness, the daily requirement for parenteral hydrocortisone is 40-100 mg/m2/24h (approximately 3-10 times the maintenance dose) in 3-4 divided doses.
With a major decline in the clinical condition of the patient (eg, development of hypotension, fever, decreasing mental status, acute intercurrent illness), promptly initiate treatment for possible adrenal crisis even before the diagnosis is confirmed.
The treatment of an adrenal crisis includes fluid, dextrose, and glucocorticoid replacement in order to restore fluid volume and prevent hypoglycemia and death. Adequately treat any precipitating event such as an infection.
Fluids administered (eg, 0.9% NaCl with 5% dextrose) should be administered at 1.5-2 times the maintenance rate (2250-3000 mL/m2/d). If the patient presents in shock, administer 0.9% NaCl (10-20 mL/kg) during the first hour of treatment. In addition, cortisol as a soluble ester (21-hemisuccinate or 21-phosphate) must be administered as an immediate IV bolus and every 6 hours (25 mg for infants; 50 mg for small children; 100-150 mg for larger children or adolescents).
Once the clinical condition improves, gradually taper down the steroid dosage by one third every day until the patient is back to maintenance dose.
All patients with FGD on replacement glucocorticoid therapy must be instructed on appropriate sick day management to adjust steroid dosage and taught how to administer parenteral hydrocortisone at home in cases of severe stress or when oral intake is compromised, and they should be provided a 24-hour physician contact number in case of emergency.
All patients with FGD should wear a MedicAlert bracelet outlining their condition and medical treatment. Because of the rarity of this condition, provide families with a physician letter outlining FGD and its potential complications and treatments to present to an emergency care facility if a visit to the emergency department becomes necessary.
Achalasia and alacrima
In those cases of FGD associated with achalasia and alacrima, these conditions should be carefully monitored and managed. See Allgrove (AAA) Syndrome for full details.
FGD associated with achalasia and Allgrove syndrome (AS) requires surgical intervention.
Consultations
Geneticist
Counsel patients with FGD and their families regarding the inheritance pattern of FGD, which is autosomal recessive.
Observe siblings and other close relatives for potential symptoms of FGD.
Screen family members with a Cortrosyn stimulation test to exclude this condition, which is potentially fatal if unrecognized and untreated.
Some cases of FGD have been associated with mutations in the MC2R gene. Confirming this diagnosis by DNA analysis may be possible in some cases.
In individuals with FGD associated with alacrima, achalasia, or AS, other consultations are warranted, including an ophthalmologist to assess alacrima and a neurologist to assess development and to address the neurologic manifestations of AS (see Allgrove (AAA) Syndrome).
