Date post: | 18-Jan-2016 |
Category: |
Documents |
Upload: | laura-ford |
View: | 216 times |
Download: | 0 times |
DISORDERS OF THE ADRENOCORTICAL
HORMONES
Dr. Ayisha QureshiMBBS, Mphil
Hypoadrenalism- ADDISON’S DISEASE
ADDISON’S DISEASE
DEFINITION:Addison’s disease results from the inability of the
adrenal cortices to produce the adrenal hormones & this is most frequently caused by the primary atrophy
of adrenal cortex. CAUSES:1.Autoimmune disorder2.Tuberculous destruction of the glands3.Cancer4.Secondary to impaired pituitary gland function leading to insufficient ACTH production.
Signs & Symptoms
Mineralocorticoid deficiency• Greatly decreased renal
sodium reabsorption• Increased loss of Na, Cl &
water in the urine• Decreased ECF/ hypovolemia• Hyponatremia• Hyperkalemia• Mild Acidosis• Increased RBC conc. Due to
decreased ECF• Decreased CO• Shock • Death
Glucocorticoid deficiency• Patient cannot maintain
normal blood glucose levels as no gluconeogenesis b/w meals
• Nausea, vomiting, fever, hypotension
• All metabolisms effected• Patient highly susceptible to
the deteriorating effects of stress.
• Even mild infections can lead to death
Signs & Symptoms• Extreme melanin pigmentation of the mucous membranes &
skin.• Usually deposited in blotches• Cause is increased ACTH secretion as well as increased
MSH secretion WHAT IS POMC & MSH? Proopiomelanocortin (POMC) is a preprohormone which when
cleaved causes the formation of:• MSH (melanocyte stimulating hormone) which causes
darkening of the skin by stimulating formation of melanin & dispersing it to the epidermis
• Beta Lipoprotein• Beta endorphin & few others
(ACTH also has 1/30 as much activity of MSH & so its hypersecretion also causes Hyperpigmentation of the skin.)
TREATMENT
• A person with complete destruction of the adrenal may die within a few days to 2 weeks b/c of weakness & circulatory shock.
• However, if small quantities of mineralo & glucocorticoids are administered daily, they can live for years.
Hyperadrenalism- Cushing’s Syndrome
DEFINITION:Hypersecretion by the adrenal cortex causes a complex cascade
of hormone effects called Cushing’s syndrome. CAUSES: •Exogenous
- Factitious- Iatrogenic
•ACTH-Dependant- Pituitary adenoma- Ectopic ACTH syndrome
•ACTH-Independant- Adrenal adenoma- Adrenal carcinoma
When Cushing’s syndrome is secondary to excess secretion of ACTH by the anterior
pituitary, it is called CUSHING’S DISEASE.
Signs & Symptoms
• Truncal Obesity• Supraclavicular & dorsal
fat pad• Buffalo hump• Moon Facies• Purple striae due to
decreased collagen proteins
• Thin skin• Capillary fragility & easy
bruising• Hirsuitism
• Diabetes Mellitus also called Adrenal Diabetes
• Thin extremities and severe muscle weakness due to increased protein catabolism
• Infections due to suppressed immune system with impaired wound healing
• Osteoporosis • Hypertension
Diagnosis & Treatment
DIAGNOSIS:•Very challenging•Diagnose excess Cortisol (24 hour urine cortisol & midnight salivary cortisol level) •Dexamethasone suppression testTREATMENT:•Removal of the cause: Surgery of the adrenal tumour OR pituitary tumour•Drugs that block steroidogenesis.e.g. Ketaconazole•Drugs that inhibit ACTH secretion.e.g. Serotonin antagonists•Partial or total adrenalectomy
PRIMARY ALDOSTERONISM(CONN’S SYNDROME)
DEFINITION:Occasionally, a small tumor of the zona glomerulosa
cells occurs & secretes large amounts of aldosterone; the resulting condition is called
“Primary aldosteronism” or “ Conn’s disease”.CAUSES: •Small tumour of Zona Glomerulosa cells that secretes large amounts of Aldosterone.•Sometimes even hyperplastic adrenal cortices secrete aldosterone instead of cortisol.
Signs & Symptoms
• Severe hypokalemia causing muscle paralysis
• Increased blood and ECF volume
• Slight increase in Na conc.
• Hypertension
Usually, diagnosed by decreased plasma renin and increased aldosterone concentration.
ADRENOGENITAL SYNDROME
A syndrome that is caused by occasional adrenocortical tumour that secretes excessive quantities of androgens.
Signs & Symptoms
• In Females:
- Virile characteristics
- Growth of a beard
- Deeper voice
- Occasionally baldness
- Masculine distribution of hair on the body
- Deposition of proteins in a masculine manner
• In Males:- In prepubertal male, a virilizing adrenal
tumour causes same characteristics as in the female plus rapid development of the male sex organs
- In adult male, the virilising characteristics are often masked by the virilising effects of Testosterone
- Diagnosis is made by the presence of excess 17-ketosteroids in the urine.