Clinical Aspects of Endocrine Diseases (II)

Study Notes

Hyperaldosteronism involves excess secretion of aldosterone, leading to sodium retention and potassium loss.
Primary hyperaldosteronism can result from adrenal adenomas (Conn’s Syndrome) or bilateral adrenal hyperplasia.
Secondary hyperaldosteronism is caused by increased renin production due to conditions like renal artery stenosis, heart failure, or cirrhosis.
Symptoms of hyperaldosteronism include severe resistant hypertension, particularly in younger individuals.

Key investigations: plasma aldosterone levels (diurnal and postural), plasma aldosterone-renin ratio, serum electrolytes, and urinary electrolytes.
Imaging techniques like CT/MRI are used for adrenal assessment.
Treatment includes surgical removal of adenomas and medication (spironolactone, eplerenone, amiloride).

Pheochromocytoma is a tumor of the adrenal medulla derived from sympathetic nerve tissue, with 10% being malignant.
Pathophysiology involves excessive secretion of adrenaline and noradrenaline, often in an intermittent manner and could lead to sudden death.
Investigations include urinary metanephrines, vanillylmandelic acid, CT/MRI of the adrenal glands, and 131I MIBG scans.

Surgical removal is the primary treatment method.
Preoperative patient preparation involves alpha blockers (phenoxybenzamine) followed by beta blockers (propranolol).
In cases of severe hypertension, emergency medications like phentolamine, sodium nitroprusside, or magnesium sulfate are utilized.

Characterized by "excess production of tasteless urine," DI can be differentiated into cranial, nephrogenic, dipsogenic, and gestational types.
Cranial DI results from hypothalamic disease leading to a deficiency of ADH, presenting with polyuria and excess thirst.
Investigations reveal hypernatremia, hyperosmolality, and failure to concentrate urine under water deprivation.

Treatment includes desmopressin (synthetic ADH), carbamazepine, and chlorpropamide for cranial DI.
Nephrogenic DI is caused by renal unresponsiveness to ADH and is managed by addressing the underlying renal disease or lithium treatment.

SIADH causes water retention due to excess ADH, resulting in hypervolemia and natriuresis.
Symptoms are nonspecific but may include confusion, nausea, irritability, seizures, and coma.
Investigations include plasma osmolality, serum electrolytes, and hormonal levels (ACTH, TSH).

Treatment involves fluid restriction and medications like demeclocycline and hypertonic saline.
Vasopressin receptor antagonists, such as tolvaptan, are also utilized.

Insulinoma is a tumor of pancreatic beta cells causing recurrent hypoglycemia.
Diagnosed through Whipple’s triad: symptoms of hypoglycemia induced by fasting/exercise, biochemical evidence, and relief of symptoms by glucose.
High fasting insulin or C-peptide levels confirm diagnosis; a 72-hour fasting may be required.

Specific details regarding APS were not provided in the text, generally defined as a group of disorders with multiple endocrine gland dysfunctions.

The details on MEN were not outlined but refer to genetic disorders leading to tumors in multiple endocrine glands.

CAH is an autosomal recessive disorder with six major types.
Characterized by the diversion of glucocorticoids and mineralocorticoids to androgen production, causing adrenal hyperplasia.
Clinical presentations can include ambiguous genitalia in females, virilization, adrenal failure, and salt-wasting, often evident at birth or in childhood.