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CASE FILES: BIOCHEMISTRY
A N SW E R S TO C A SE 49: A D D ISO N D ISE A SE
Summary:
A 36-year-old male presents with fatigue, weakness, nonspecific GI
symptoms, hypotension, and darkening skin coloration despite being away
from sunlight.
Diagnosis: Addison disease
Underlying problem: Adrenal insufficiency with lack of
mineralocorticoids and cortisol
C L IN IC A L C O R R E L A T IO N
This 36-year-old male has the clinical stigmata of Addison disease, or adreno-
corticoid deficiency. The weakness, fatigue, and hypotension are caused by
decreased levels of cortisol as well as mineralocorticoids. The darkening of the
skin is a result of increased melanocyte-stimulating hormone, which is metabo-
lized from adrenocorticotropin hormone (ACTH), which is elevated because of
the low levels of the adrenal hormones. This is a potentially fatal disorder and
requires prompt clinical recognition. Serum electrolytes give a clue to the disor-
der, because the patient would likely have hyponatremia and hyperkalemia. An
ACTH stimulation test revealing low levels of adrenal corticoid response is con-
firmatory. The treatment includes hydrocortisone (cortisol) to replace glucocorti-
coid deficiency and a mineralocorticoid supplementation. The most common
cause of adrenal insufficiency on a chronic basis is autoimmune destruction of the
adrenal gland. Other autoimmune diseases should be sought, such as diabetes
mellitus and systemic lupus erythematosus. Adrenal insufficiency may occur
acutely when the adrenal gland is not able to generate high levels of steroids in
times of stress, such as surgery or infection; the most common reason in these
cases is chronic corticosteroid therapy leading to relative adrenal suppression.
These situations can be avoided by the administration of a “stress dose” hydro-
cortisone intravenously around the time of anticipated physiologic stress.
A PPR O A C H TO A D R E N A L H O R M O N E S
O bjectives
1.
Be familiar with the clinical manifestations of mineralocorticoid
deficiency.
2.
Know about the regulation of ACTH and cortisol.
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