Autoimmune hypophysitis

Autoimmune hypophysitis
Synonyms	Lymphocytic hypophysitis
Pronounce	N/A
Specialty	N/A
Symptoms	Headache, visual field defects, hormonal deficiencies
Complications	Adrenal insufficiency, hypothyroidism, diabetes insipidus
Onset	Typically in pregnancy or postpartum
Duration	Chronic
Types	N/A
Causes	Autoimmune disease
Risks	Pregnancy, female sex
Diagnosis	MRI, hormonal assay
Differential diagnosis	Pituitary adenoma, Rathke's cleft cyst, sarcoidosis
Prevention	N/A
Treatment	Glucocorticoids, immunosuppressive therapy, surgery
Medication	N/A
Prognosis	Variable, depends on response to treatment
Frequency	Rare
Deaths	N/A

Other Names: LYH; LH; Lymphocytic hypophysitis Lymphocytic hypophysitis (LH) is a condition in which the pituitary gland becomes infiltrated by lymphocytes, resulting in pituitary enlargement and impaired function. It most often occurs in women in late pregnancy or the postpartum period, but can also occur in prepubertal or post-menopausal women, and in men.

Epidemiology

A large scale study on cadavers done in Sweden, performed biopsies on hundreds of pituitary glands. The study indicated that perhaps as much as 5% of the population experiences some amount of autoimmune pituitary destruction. It is further hypothesized that perhaps half that many show, or may experience, clinical manifestations.

Cause

The exact cause of lymphocytic hypophysitis (LH) is still under debate and remains unclear. It has been suggested that LH has an autoimmune etiology. This has generally been supported by the frequent postpartum occurrence and the lymphocytic infiltration, as well as several histopathological, laboratory and clinical findings.

Signs and symptoms

Individuals affected with lymphocytic hypophysitis typically have headaches as their first symptom. This usually precedes or occurs with visual field impairment; rarely, double vision (diplopia) may be present. Hyperprolactinemia affects approximately one third of individuals, causing amenorrhea (absence of menstruation) or galactorrhea (production of breast milk) in women and sexual dysfunction in men. Other features that occur more rarely and are related to alterations in pituitary secretions may include:

• hypoprolactinemia (deficiency of prolactin)
• subclinical hypopituitarism (decreased production of pituitary hormones with no symptoms)
• ACTH deficiency
• acute adrenal crisis
• hypogonadotropic hypogonadism (usually diagnosed only in males)
• isolated growth hormone (GH) deficiency

Diagnosis

Biopsy is the only means of accurate diagnosis as no autoantigen has been discovered. Biopsy of the pituitary gland is not easily performed with safety as it sits under the brain, however, a test does exist to detect antibodies to the pituitary without biopsy: autoantibodies to M(r) 49,000 pituitary cytosolic protein may represent markers for an immunological process affecting the pituitary gland. Tests for normal pituitary gland hormone production tend to be expensive and in some cases difficult to administer. In addition, certain hormone levels vary largely throughout the day and in response to metabolic factors, making abnormal levels difficult to calibrate—further hampering diagnosis. Transsphenoidal surgery (accessed "through the nose") to confirm diagnosis and save viable pituitary tissue may be required in individuals with symptoms or signs of severe compression. Visual improvement following decompression with this type of surgery has been reported. In some cases, pituitary biopsy is both diagnostic and therapeutic, because after this procedure a progressive recovery of pituitary function may occur.

Treatment

Lymphocytic hypophysitis can evolve differently among affected individuals, so different treatment strategies may be required. Some individuals experience spontaneous remission (improvement or reversal of the condition without any formal treatment). Careful follow-up is typically recommended. Many affected individuals only have headaches as a manifesting symptom, and there have been multiple reports of these individuals improving with glucocorticoids alone. Although the use of glucocorticoids or other anti-inflammatory and immunosuppressive drugs have been suggested as medical treatment, their long-term efficacy still needs to be confirmed. High-dose methylprednisolone pulse therapy (short, intensive administration given at set intervals) seems to be effective in about 30% of treated patients. Transsphenoidal surgery (accessed "through the nose") to confirm diagnosis and save viable pituitary tissue may be required in individuals with symptoms or signs of severe compression. Visual improvement following decompression with this type of surgery has been reported. In some cases, pituitary biopsy is both diagnostic and therapeutic, because after this procedure a progressive recovery of pituitary function may occur.

NIH genetic and rare disease info

• NIH info on Autoimmune hypophysitis

Autoimmune hypophysitis is a rare disease.

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