Hypopituitarism

Clinic

• Decreased secretion of one or more of 8 hormones normally produced by the pituitary gland at the base of the brain.
• If there is decreased secretion of one specific pituitary hormone, the condition is known as selective hypopituitarism.
  • Panhypopituitarism
  • Autoimmune hypophysitis

Autoimmune hypophysitis

• It can affect Anterior or posterior part of pituitary gland
  • Lymphocytic Infundibuloneurohypophysitis (LINH): Posterior pituitary is affected resulting in Central diabetes insipidus.
  • Lymphocytic Adenohypophysitis (LAH): Anterior pituitary gland is involved.
  • In some cases, pituitary inflammation leads to interruption of dopamine flow from the hypothalamus into pituitary causing Hyperprolactinaemia Surprisingly HPV and HHV-6 is seen in pituitary adenoma.

LINH

• Infundibulo-neuro-hypophysitis is a rare, acquired pituitary hormone deficiency, a type of primary hypophysitis
• It is characterized by an inflammation of the posterior pituitary and the stalk.
• The major clinical manifestation is diabetes insipidus with polyuria and polydipsia.
• It has also Post-Node sign / Symptoms due to pressure effect of Pituitary adenoma including nausea, vomiting, visual disturbances / dizziness
• They may have fatigue, loss of libido, amenorrhea due to
• Mass effects on adjacent structures (e.g. optic chiasm)

LAH

• LAH occurs when the anterior pituitary cells are affected by autoimmune (Lymphocytic) inflammation resulting in
  • Adrenal insufficiency (ACTH producing cells are affected)
  • Hypothyroidism (TSH producing cells are damaged)
  • Hypogonadism (LH and/or FSH producing cells are involved).
• Causation: MTB (Tuberculosis Hypophysitis)

Hyperprolactinaemia

• Hyperprolactinemia inhibits the secretion of GnRH / FSH and LH results in hypogonadism.
• Hyperprolactinemia may cause
  • Galactorrhea
  • Infertility
  • Abnormal menstrual period
  • Hypogonadism
  • Erectile dysfunction
  • Gynecomastia

• 17% of PCOS have Hyperprolactinaemia

Both anterior and posterior pituitary

Lymphocytic infundibular panhypophysitis

Signs / Symptoms

• The most common problem is insufficiency of FSH and/or LH leading to sex abnormalities.
• Growth hormone deficiency is more common in people with an underlying tumor than those with other causes.

Related disease

• Autoimmune thyroiditis: HCV, MMP, EBV, MTB
• Pernicious anemia: EBV, HCV
• SLE
• Rheumatoid arthritis
• Dacryoadenitis : EBV, MMP, MTB
• ipilimumab: monoclonal antibody drugs

Hyphophysitis & thyroiditis

• 80% of patients with pituitary antibodies also have antibodies to thyroid gland or its hormones.
• Likewise, 20% of autoimmune thyroid patients also have pituitary antibodies.
• It follows that a subset of thyroid patients may have a disease related to autoimmune hypophysitis