Image Based Question – 72054

Correct Answer » A Explanation

Ans:A. Hypoglycemia.

Image shows:This photograph shows reddish-purple stretch marks on the belly and under the arms in a person with Cushing’s syndrome.

CUSHING’S SYNDROME

• Most common cause is latrogenic (excess steroids/ACTH)

• Most common endogenous cause is ACTH producing pituitary adenoma (Cushing’s disease)

Etiology

↑ Cortisol + ↑ ACTH

• ACTH producing pituitary micro/macroadenoma

• Ectopic ACTH producing tumors: occult carcinoid tumors – mc lung

↑ Cortisol + ↓ACTH:

• Exogenous steroid administration

• Adrenal adenoma

• Adrenal carcinoma

Clinical features:

• Body fat: Weight gain, central obesity, rounded (moon) face, fat pad on back of neck (buffalo hump)

• Skin: Facial plethora, thin skin and visible capillaries, easy bruising, purple striae, acne, hirsuitism

• Bone: Osteoporosis, decreased linear growth in children, exuberant callus with fractures

• Muscle: Weakness, proximal myopathy (prominent atrophy of gluteal and upper leg muscles)

• CVS: Hypertension, hypokalemia, edema, atherosclerosis

• Endocrine: Hyperglycemia (adrenal diabetes), dyslipidemia

• Reproductive system: Decreased libido, in women amenorrhea

• GIT: peptic ulcer

• CNS: insomnia, irritability, emotional lability, depression, in severe cases, paranoid psychosis

• Blood and immune system: Increased susceptibility to infections (bacterial and fungal), increased WBC count, eosinopenia, hypercoagulation with increased risk of deep vein thrombosis and pulmonary embolism

• Others: poor wound healing, Wasting and weakness of proximal thigh muscles.

Diagnosis two steps:

STEP 1: Establishing the presence of Cushing’s syndrome by using the screening tests

• Increased 24-hour urine free cortisol (3 times)

• Failure to suppress serum cortisol with low doses of oral dexamethasone

• Overnight dexamethasone suppression test (ONDST): (easiest of all) 1 mg dexamethasone given at 2300 hrs and measuring serum cortisol at 0900 hrs the following day.

• Low-dose dexamethasone suppression test (LDDST), serum cortisol is measured following administration of 0.5 mg dexamethasone 4 times daily for 48 hours

• Midnight plasma or salivary cortisol level

• Loss of the normal circadian rhythm of cortisol, with inappropriately elevated late-night serum or salivary cortisol.

STEP 2: Determining the underlying cause

• Excess cortisol secretion + undetectable ACTH (below 5 pg/mL) adrenal cause

• Excess cortisol secretion + ACTH levels greater 15 pg/mL pituitary cause or ectopic ACTH.

• High-dose dexamethasone suppression test (HDDST) – serum cortisol is measured before and after administration of 2 mg of dexamethasone 4 times daily for 48 hours.

• In pituitary-dependent Cushing’s disease

• ACTH secretion is suppressed by high dose dexamethasone

• ACTH is stimulated by corticotrophin-releasing hormone (CRH)

Treatment:

• Cushing’s disease: treatment of choice – removal of the pituitary corticotrope tumor, usually via a transsphenoidal approach. If pituitary disease recurs, options include second surgery, radiotherapy, stereotactic radiosurgery, or bilateral adrenalectomy

• Following bilateral adrenalectomy there is a risk of Nelson’s syndrome (aggressive pituitary macroadenoma with very high ACTH levels) – prevented by pituitary irradiation

• Cushing’s syndrome: metyrapone and Ketoconazole

• Adrenocortical carcinoma: mitotane