Adrenal Disorders Flashcards
What is the mass of the adrenal gland
3-5 grams each
What are the various regions of the adrenal cortex and what they produce
Zona Glomerulosa : Aldosterone (Mineralocorticoid)
Zona Fasiculata : Cortisol (Glucocorticoid)
Zona Reticularis : Dihydroepiandrosterone (DHEA) (Androgen)
What does the inner medulla of the adrenal gland produce
Catecholamines
What are the functions of aldosterone
Acts on renal tubules,intestines, sweat gland)
Sodium reabsorption
K+ excretion
H+ excretion
Water reabsorption
Increase ECF volume
Increase blood volume & maintain blood pressure
What are some functions of cortisol
Effects on carbohydrates, protein & fat metabolism
During acute trauma, exercise, infection, operations and other stresses
Increased cortisol
Increased glucose & fatty acid releases for energy
Anti-inflammatory actions
Maintain adequate vascular tone during stress
What are functions of adrenal androgens
Early development of male sex organs during childhood
Growth of pubic & axillary hairs
Promote protein synthesis
What are some disorders of the adrenal cortex
Adrenal hypofunction – Addison’s disease
Adrenal hyperfunction :
Cushing syndrome (Mainly hypercortisolism)
Conn’s syndrome (Hyperaldosteronism)
Congenital Adrenal Hyperplasia (CAH)
What are the two main adrenal hyper-function disorders
Cushing’s syndrome
Conn’s syndrome
What are some disorders of the adrenal medulla
Pheochromocytoma
What causes primary hypoadrenalism
Destruction of the adrenal cortex by any process producing deficiency of aldosterone, cortisol and adrenal androgens
What causes secondary hypoadrenalism
Secondary hypoadrenalism is caused by deficiency of ACTH
What is the ratio of contraction of Addison’s disease (male:female)
3:1
What are some etiologies (risk factors) of Addison’s disease
Autoimmune
Tuberculosis
Glucocorticoid treatment
Surgical bilateral adrenalectomy
Secondary tumour deposits
Fungal disorders – Histoplasmosis
Hemochromatosis, amyloidosis, sarcoidosis,
Adrenal haemorrhage : septicaemia, anticoagulant therapy, waterhouse – Friderichsen syndrome, bleeding disorders.
Radiation therapy
What are some clinical features of Addison’s disease
Generalized weakness, fatigue, lethergy.
Anorexia, weight loss, nausea, vomiting.
Dizziness, postural hypotension, dehydration, shock.
Muscle, joint pain, fever.
Loss of body hairs, menstrual abnormalities.
Hyper-pigmentation of the palms of the hand
Depression
What are some laboratory investigations for Addison’s disease
Plasma Cortisol – Low to absent.
Plasma ACTH – High ( in primary hypoadrenalism)
ACTH Stimulation Test:
Morning plasma cortisol
ACTH ( Cosyntropin) 250 mg I/M or I/V
Second plasma cortisol level after 30, 60 mins.
Cortisol level fail to rise appropriately after ACTH suggestive of Addison disease
Hyperkalaemia, hyponatraemia.
Increased urea
Hypoglycaemia
Mild anaemia, Neutropenia, Eosinophilia
Anti-adrenal antibodies.
What is another name for Cushing’s syndrome
Hypercortisolism
What are some radiological investigations to make in Addison’s disease
Chest X-ray – R/O Tuberculosis
Abdomen X-ray – R/O Tuberculosis
Ultrasound abdomen
CT abdomen
What is another name of Addison’s disease
Primary Adrenal Insufficiency
What is Cushing’s syndrome
Cushing’s syndrome refers to manifestations due to excessive glucocorticoids in the body. Generally affect young ( mean age 33 years). Common in females 5 :1
What are some etiology of Cushing’s syndrome
ACTH hypersecretion by pituitary (Cushing disease) (Pituitary adenomas)
ACTH hypersecretion by ACTH producing tumors (small cell carcinoma lungs, carcinoid tumors, thymus, pancreas)
Excessive cortisol secretion by adrenal neoplasm (Adrenal adenoma, carcinoma) & hyperplasia
Prolonged corticosteroid treatment
What are some clinical features of Cushing’s syndrome
Effects of Glucocorticoid Excess:
Central obesity, moon face, dorsocervical fat pad, (buffalo hump), supraclaviculer fat pad, protuberant abdomen
Muscle wasting, weakness, fatigue.
Thin skin, easy bruisability, purple striae, poor wound healing, osteoporosis
Hypogonadism, menstrual abnormalities, decrease libido.
Psychosis, depression, impaired memory
Children (Slow growth)
Effects of androgen excess: ( if present)
Hirsuitism, acne, virilization in females
Pseudoprecocious puberty in children
Effects of ACTH excess: (if present)
Hyperpigmentation
Effects of mineralocorticoid excess: (if present)
Hypertension
Hypokalaemia
Effects of pituitary tumour: (if present)
Headache
Visual field defects
Hypopituitarism
How do you diagnose hypercortisolism
Establish diagnosis of hypercortisolism
Find out the cause of hypercortisolism. Is it?:
Adrenal source
Pituitary pathology (Cushing disease)
Ectopic ACTH producing tumors
Plasma cortisol concentrations are at their highest shortly after waking and then decline throughout the day to reach a nadir in the late evening.
Because of this variation, it is important that blood samples are taken at times that coincide with either the peak or the trough
Investigations
To establish the diagnosis of hypercortisolism:
Plasma cortisol:
In normal individuals:
Morning samples at 0800 Hrs: 10 – 28 ug/dl
Evening samples at 2000 Hrs: 5 – 10 ug/dl
In Cushing syndrome:
Plasma cortisol high
Loss of diurnal variation
High level also found in stress, obesity, depression, pregnancy, alcoholism
To differentiate we perform DMX Suppression test
Overnight Dexamethasone Suppression Test:
Best Screening Test
2mg oral dexamethasone given at 2300 Hrs.
Blood specimen for plasma cortisol-next morning at 0800Hrs
Normal individuals: Plasma Cortisol Suppressed to < 50% of basal level.
Cushing Syndrome: Failure to suppression of plasma cortisol levels
Prolonged Dexamethasone Suppression Tests.
Low dose: 0.5 mg six hourly for first two days.
If suppressed : Normal
No suppression : Go with high dose
High dose: 2.0 mg six hourly for next two days
If suppressed : Cushing’s disease
No Suppression : Adrenal tumor - ACTH secreting tumour
To find out the cause of hypercortisolism:
Plasma ACTH:
High plasma ACTH
Pituitary Adenoma (Cushing’s disease)
Ectopic ACTH secretion by tumors
Low plasma ACTH
Adrenal tumors
Other laboratory tests:
Urinary free Cortisol: High
Plasma glucose : High due to anti Insulin effect of Cortisol
Serum K : ± low due to mineralocorticoid effects of cortisol in more severe ACTH dependent disease
Leukocytosis with lymphopenia
Talk about Conn’s syndrome
Excessive production of aldosterone
Hypertension (usually mild), polyuria, fatique and weakness.
Hypokalemia, metabolic alkalosis.
Elevated plasma & urine aldosterone
Suppressed plasma renin.
Adrenal adenoma (75%), bilateral adrenocortical hyperplasia (25%).
CT/MRI of adrenal.
What are some radiological investigations for Cushing’s syndrome
For localization of tumors
MRI – pituitary
CT Scan – chest, abdomen
CT Scan – Adrenals
Radioisotopic studies:
Distinguish adrenal adenoma from hyperplasia
