396 DISEASES/DISORDERS
Bacterial folliculitis (pyoderma): excess glucocorticoids predispose to skin infections
from bacterial overgrowth and poor immune response.
Dystrophic mineralization may occur in tissues other than the skin: renal pelvis,
skeletal muscles, gastric walls, bronchial walls, heart muscle, blood vessels, and liver.
Muscle weakness and atrophy: excessive protein catabolism and muscle wasting; cru-
ciate ruptures can occur with little stress; high levels of cortisol may cause myotonia
characterized by stiff extensor muscles.Anestrus: glucocorticoids exhibit a negative feedback on pituitary gonadotrophin
secretion.
Testicular atrophy and decreased libido: glucocorticoids exert a negative feedback on
pituitary gonadotrophin secretion, which causes a decrease in testicular androgen
production.Clitoral hypertrophy: excess androgen production; major source of androgen produc-
tion in the female is the adrenal gland.
Perianal gland adenomas: females and neutered males; overproduction of androgens.
Panting: common finding and may be due to wasting of the muscles of respiration as
well as reduced capacity for thoracic expansion from the distended abdomen; other
possible causes include pulmonary hypertension and decreased compliance, primary
CNS disturbance, or pulmonary mineralization.Dyspnea: uncommon; associated with pulmonary thromboembolism; life-threatening
complication of HAC; may occur secondary to a hypercoagulable state, erythrocytosis,
and/or hypertension.Hyperpigmentation: possibly due to the similarity of ACTH to melanocyte-
stimulating hormone (MSH).
Blindness and papillary light reflex changes: pressure exerted on the optic chiasm by
macroadenomas.
Central nervous system signs: seizures, pacing, head pressing, circling, behav-
ioral change (timid/aggressive), impaired thermoregulation (unexplained fever or
hypothermia), ataxia, coma, death; usually due to pituitary macroadenoma and space-
occupying effect; can occur after initiation of antiadrenal therapy due to lack of neg-
ative feedback and subsequent tumor expansion (Nelson’s syndrome).DIFFERENTIAL DIAGNOSIS
Hypothyroidism
Sex hormone dermatoses
Acromegaly
Diabetes mellitus
Hepatopathies
Renal disease
Other causes of polyuria/polydipsia
Follicular dysplasias
Alopecia X/atypical hyperadrenocorticism