Pituitary gland disorders

Considerations

The anterior pituitary gland produces:

ACTH: Over production of ACTH, usually the result of a basophil micro-adenoma, can result in Cushing’ disease because of adrenal cortex overstimulation.

The symptoms and signs may include central obesity, hypertension, plethora, poor wound healing, striae, easy bruising, diabetes, osteoporosis and muscle atrophy.

The treatment is by trans-sphenoidal excision of the adenoma.

Prolactin: Over production of Prolactin is usually the result of a micro-adenoma (size less than 1cm) or macro-adenoma (size 1 cm or more). Large adenoma may affect the anatomy of the Sella Turcica and compress the optic chiasma.

The symptoms and signs include galactorrhoea, menstrual cycle disturbance, visual fields defects, headaches and well as low testosterone levels in males.

Prolactin levels are increased. Brain MRI and CT demonstrate the enlarged pituitary gland and its surroundings. Treatment is by Dopamine antagonists, e.g. Cabergoline, which should be taken long term. Rarely surgery is required to decompress the Sella Turcica.

It is important to note that Cabergoline and similar medication may affect behaviour in a manner that is of concern to flight safety.

Growth hormone: Overproduction of growth hormone results in acromegaly. The symptoms and signs include increased bone size that is most visible on hands, feet and face. Soft tissues enlargement also occurs with thicken skin, lips, tongue and ears enlargement.

The key biochemistry tests include insulin like growth factor 1 (IgF-1) level determination which may show an elevation, and GH determination following oral glucose loading which normally suppresses GH significantly but not in acromegaly. MRI will generally show the pituitary tumour.

If no tumour is seen a GHRH level may reveal the existence of a non-pituitary GHRH producing tumour somewhere else in the body. Treatment is most often surgical but also by irradiation and medication.

The posterior pituitary gland produces

Antidiuretic Hormone (Vasopressin - ADH): Underproduction results in polyuria (Diabetes Insipidus). Fluid deprivation secures the diagnosis if the urine remains diluted despite a raise in osmolality over 295 mOsm/kg. Treatment is by titrated Desmopressin, usually administered as a nasal spray.

Information to be provided

On the first occasion that an applicant presents with a pituitary gland disorders:

• All specialists and investigations reports relating to the condition;
• A recent endocrinologist report, to include comments on risk of deterioration;
• Associated investigations results;
• Visual fields testing in case of pituitary macroadenoma.

On subsequent occasions that an applicant present with a history of pituitary gland disorder:

• Copy of all interim specialists and investigations reports relating to the condition;
• An endocrinologist report and associated investigations reports, as necessary. A report dated within the past 6 months will often be sufficient.

Disposition

• An applicant who first present with a history of pituitary gland disorder should be considered as having a condition that is of aeromedical significance.
• An applicant with a history of ACTH over production (Cushing’s syndrome) should be considered as having a condition that is of aeromedical significance.
• An applicant with a history of overproduction of Growth Hormone (GH - Acromegaly) should be considered as having a condition that is of aeromedical significance.
• An applicant with a history of over production of Prolactin may be assessed as having a condition that is not of aeromedical significance if:
  • A previous assessment under the flexibility process has concluded favourably;
  • The adenoma is classified as micro-adenoma (< 1cm);
  • The adenoma did not result in any functional compromise such as visual field defect, other hormonal compromise and / or compression of surrounding structures;
  • The applicant is undergoing regular review by an endocrinologist and the most recent report is satisfactory;
  • The applicant is asymptomatic and complies with treatment;
  • Medication is well tolerated.
• An applicant with inappropriate secretion of ADH (Diabetes Insipidus) may be assessed as having a condition that is not of aeromedical significance if:
  • A previous assessment under the flexibility process has concluded favourably.
  • The applicant is undergoing regular review by an endocrinologist and a recent satisfactory report is available;
  • The applicant is asymptomatic and complies with the treatment;
  • The treatment is well tolerated;
  • The applicant’s certificate is endorsed with the requirement not to exercise the licence privileges if medication has been omitted on the day.