Congenital Adrenal Hyperplasia Flashcards
What is the aetiology and pathology of CAH?
Autosomal recessive disorder (most types are)
Affects both sexes equally
Gene:
CYP21 - absent or changed =
21β-hydroxylase deficiency (most common)
Aldosterone + cortisol not produced but production of androgens are not affected
Low cortisol feeds back to pituitary - high ATCH
How does CAH present?
Hypotension (21β deficiency; hypertensive if 11β or 17alpha)
Ambiguous genitalia
Virilization (in the female genotype)
And/or precocious puberty (in both males and females)
Irregular menstrual cycles, infertility
Problems:
Hypoglycemia
Adrenal crisis → vomiting and diarrhea → dehydration and shock within the 1st 7-14 days
Failure to thrive
Hyperpigmentation in areas that are not exposed to sunlight (e.g., palm creases, mucous membranes of the oral cavity, and/or genitalia) is a common feature in all forms of CAH - due to co-secretion with melanocyte-stimulating hormone (MSH)
What blood results would you expect in CAH?
Acutely: Addisonian crisis
Hyponatraemia + hyperkalaemia + metabolic acidosis (because no aldosterone - no ENaC channel activation - salt wasting = H+ retention as co transported)
Will also be: High ATCH Low Cortisol Low aldosterone High androgens
How do you manage an Addisonian crisis?
ABCDE
The 4 S’s of adrenal crisis treatment are:
Salt: 0.9% saline
Sugar: 50% dextrose
Steroids: 100 mg hydrocortisone IV every 8 hours
Support: normal saline to correct hypotension and electrolyte abnormalities
Also will be hyperkalaemic:
IV calcium gluconate - cardioprotective
Salbutamol (IV/NEB) or insulin + glucose (IVI)
Calcium resonium PO (K+ chelator)
How do you manage CAH in the long term?
Life long replacement of:
Glucocorticoids - hydrocortisone (neonates/paeds); prednisolone or dexamethasone (teens/adults)
(MUST BE INCREASED DURING PERIODS OF STRESS E.G. SEPSIS)
Mineralocorticoids - fludrocortisone
Possible genital reconstruction
