CHAPTER 27 HYPERADRENOCORTICISM, FELINE SKIN FRAGILITY SYNDROME 411
or a sex hormone-secreting adrenal neoplasia; cortisol levels measured before and 30
minutes after administration of intravenous 0.125 mg synthetic corticotropin.LDDST: requires use of 0.1 mg/kg dexamethasone IV (10×higher dose than dogs).
HDDST: requires 1 mg/kg dexamethasone IV; unreliable for discriminating between
ADH and PDH – 50% of PDH cases will fail to suppress.
Endogenous plasma ACTH levels: must be collected on EDTA and immediately
chilled; high levels expected with PDH, low levels expected with ADH.
Imaging
Abdominal ultrasonography: bilateral symmetric adrenal glands (normal to increased
size) with PDH; unilateral adrenomegaly with ADH – adrenal masses are often small
until end-stage disease; may be useful to assess for abdominal metastases and tumor
expansion into the vena cava in cases of ADH.CT and MRI: small pituitary tumors (microadenomas) may be difficult to visualize;
MRI may be more successful.
Pathologic Findings
Histopathology: variable results suggestive but not diagnostic: decreased dermal
collagen; atrophic epidermis and dermis; attenuated collagen fibers.
THERAPEUTICS
Underlying metabolic disease should be ruled out.
Many patients are debilitated and require supportive care.
Surgical correction of the lacerations is not helpful because the tissue cannot with-
stand pressure from sutures.
Protect skin: clothing, reduce activities that can traumatize the skin, remove sharp
edges from the environment, prevent damage from interaction with other animals.
Hyperadrenocorticism: adrenalectomy may be the preferred treatment.
Radiation therapy: variable success in the treatment of pituitary tumors.
Drugs of Choice
Medical management: may be useful for preparing patient for surgery and for mini-
mizing postoperative complications (e.g., infections and poor wound healing).
No known effective medical therapy for feline hyperadrenocorticism.
o,p’-DDD (mitotane): 12.5–50 mg/kg PO BID; typically poor response; side effects
include anorexia, vomiting, and diarrhea.
Ketoconazole (Nizoral): 5–10 mg/kg PO BID to TID; typically poor response.
Metyrapone: 65 mg/kg PO BID.
Trilostane: 0.5–12 mg/kg PO q24h to BID; begin with 10 mg q24h and gradually
increase (as needed) to 10 mg/kg q24h based on ACTH stimulation testing; some cats