What is a pituitary gland?
Pituitary is a pea sized gland located in the brain. It is also known as the master gland as it controls the function of other endocrine glands. Pituitary is divided into anterior and posterior parts. Anterior pituitary secretes six hormones: TSH, ACTH,LH, FSH, GH and Prolactin. Posterior pituitary secretes: Antidiuretic hormone( also called vasopressin) and Oxytocin.
Disorders of pituitary gland
The major disorders of pituitary are: Acromegaly, Diabetes insipidus, Hypopituitarism, Pituitary tumour.
- Hypopituitarism: refers to partial or complete deficiency of anterior and/or posterior pituitary hormones, and may be due to primary pituitary disease or hypothalamic disease (hypothalamus is a gland that controls pituitary gland). Patients with hypopituitarism require long term hormone replacement therapy.
- Prolactinomas : is the commonest functioning pituitary tumour characterized by high levels of prolactin. Such patients may present with infertility,milky discharge of breasts, absent or delayed menses, loss of libido, headaches, visual disturbance etc. Most cases of prolactinoma can be managed with dopamine agonist drugs ( dopamine inhibits prolactin production) such as cabergoline or bromocriptine. However, sometimes prolactinomas that are big in size (macroprolactinoma) can cause visual compromise or patients may be resistant or intolerant to dopamine agonist drugs. In such special situation transphenoidal surgery will be advised.
- Acromegaly : clinical condition characterized by excessive growth hormone production due to pituitary tumours, hypothalamic disease or ectopic GHRH ( growth hormone releasing hormone) secretion. Clinical features of acromegaly are coarse facial feactures , enlarged nose, protruding jaws, enlargement of hands and feet, change in ring or shoe size, increased sweating, deep voice and so on.
- Cushing’s disease: condition characterized by excess cortisol secretion due to ACTH-secreting ( ACTH is an anterior pituitary hormone that controls cortisol production)pituitary tumor. It is a rare disease with an annual incidence of approximately 2/million. However, it has high mortality if left untreated. Clinical features include weight gain, round plethoric complexion, easy bruising , purple striae on abdomen, breasts, thigh, axilla, proximal muscle weakness, mood disturbance, menstrual disturbance and so on. The treatment options are transphenoidal surgery ( removing the pituitary tumor) or adrenelectomy.
- Diabetes insipidus: condition characterized by passage of large volumes (>3 L/ 24 h) of dilute urine due to deficiency of anti-diuretic hormone(central DI), renal resistance to anti-diuretic hormone(nephrogenic DI) or excess urination due to excessive drinking(primary polydipsia).