History and exam

Key diagnostic factors

common

history of pituitary or hypothalamic disease

Key risk factors for hypopituitarism include pituitary tumors, apoplexy, surgery, or radiation; genetic disorders such as mutations of the PROP1 gene that cause familial hormone deficiencies; and hypothalamic disease.

history of traumatic brain injury

Fractures of the skull base and traumatic brain injury can lead to isolated or multiple pituitary hormonal deficits.[6][31][40]

headaches

Often develop due to raised intracranial pressure from a space-occupying lesion in the sellar or parasellar region.

In patients who develop a sudden severe headache, the possibility of pituitary apoplexy needs to be considered.

faltering growth or short stature

Growth hormone deficiency in children.

infertility

Gonadotropin deficiency.

hypoglycemia

Adrenal insufficiency.

amenorrhea/oligomenorrhea

Suggests gonadotropin deficiency and occurs early in the sequence of pituitary hormone loss. Patients can also present with prolactin excess causing functional suppression of the pituitary gonadal axis.

galactorrhea

Seen in patients with elevated prolactin levels from stalk effect or a prolactinoma.

May be spontaneous or expressible.

delayed puberty

Absence of facial and body hair, gynecomastia, and small undeveloped testes due to gonadotropin deficiency in childhood.

uncommon

family history of pituitary hormone deficiencies

Family members may have required multiple hormone replacement therapies from childhood.

hypotension

Acute adrenal insufficiency.

visual field defects

Patients will complain of difficulty seeing into the periphery, sometimes described as tunnel vision.

ophthalmoplegia

Associated with cranial nerve invasion or impingement by a sellar or parasellar process. Patients characteristically complain of diplopia.

Other diagnostic factors

common

cardiovascular events

Attributable to relative insulin resistance and chronic growth hormone deficiency (leading to obesity, hyperlipidemia, and hypertension).[4]

cold intolerance

Thyroid hormone deficiency.

weight gain

Thyroid hormone deficiency.

erectile dysfunction and reduced libido

Seen in males with low testosterone from hypogonadotropic hypogonadism.

nausea

Adrenal insufficiency.

vomiting

Adrenal insufficiency.

fatigue

Adrenal insufficiency.

weakness

Adrenal insufficiency.

dizziness

Adrenal insufficiency.

constipation

Thyroid hormone deficiency results in reduced gastrointestinal motility.

dry skin

Thyroid hormone deficiency.

delayed relaxation of reflexes

Thyroid hormone deficiency.

uncommon

hypoactive sexual desire

Gonadotropin deficiency.

hot flashes

Gonadotropin deficiency.

nocturia and polyuria

Antidiuretic hormone insufficiency leading to diabetes insipidus.

breast atrophy

Gonadotropin deficiency.

reduced bone and muscle mass

Due to gonadotropin deficiency in both sexes. Osteoporosis may present as an atraumatic fracture or as an incidental finding on radiologic tests.

loss of axillary and pubic hair

Chronic cases of adrenal insufficiency.

Risk factors

strong

pituitary tumor

Typical clinical syndrome such as acromegaly, resulting from hypersecretion of one or more anterior pituitary hormones. Alternatively, they may present more insidiously with mass effect, with tumor expansion leading to compression of surrounding structures.[8]

Hypopituitarism resulting from pituitary adenomas is related to impaired blood flow to the normal pituitary tissue, compression of normal tissue, or interference with the delivery of hypothalamic hormones via the hypothalamus-hypophyseal portal system.

Craniopharyngiomas arise in Rathke pouch and may be cystic or solid and are commonly calcified. They commonly present with growth hormone deficiency and diabetes insipidus, with or without visual field defects.[10]

pituitary apoplexy

Denotes the sudden hemorrhagic destruction of a pre-existing pituitary adenoma. It presents with the sudden onset of an excruciating headache, visual disturbance, or ophthalmoplegia due to cranial nerve palsies (III, IV, VI).[35]

Sudden onset of adrenocorticotropic hormone deficiency and subsequent cortisol deficiency is the most serious complication and can lead to life-threatening hypotension, hyponatremia, and hypoglycemia.

Hypopituitarism caused by pituitary infarction may develop immediately or after a delay of several years, depending on the degree of tissue destruction.[15] Apoplexy usually spares the posterior pituitary. Associated risk factors for pituitary apoplexy include brain trauma, diabetes mellitus, pregnancy, anticoagulants, and blood dyscrasias.

pituitary surgery

Prompt postoperative assessment of pituitary function should be performed following surgery for pituitary adenomas.[36] Prognostic indicators for good recovery include smaller tumor size and less severe hypopituitarism prior to the surgery. At least partial recovery of pituitary function in up to 50% of patients has been reported after surgery.[37]

cranial radiation

The degree of hormonal deficits caused by radiation therapy is related to the age of exposure of the patient, the radiation dose received, and the time elapsed since the radiation exposure to the hypothalamic-pituitary axis.[34][38][39] Isolated growth hormone deficiency ensues after lower doses, whereas panhypopituitarism occurs after higher doses.

traumatic brain injury

Fractures of the skull base and traumatic brain injury can lead to isolated or multiple pituitary hormonal deficits.[6][31][40]

The pituitary stalk can be injured in deceleration injuries, such as in vehicle accidents, leading to diabetes insipidus.

genetic defects

May be of either pituitary or hypothalamic origin. Congenital deficiencies may be of isolated hormones or multiple pituitary hormones. Transcription factor defects including Pit-1, PROP1, HESX1, LHX3, LHX4, and TPIT are all associated with multiple hormone deficiencies and varying degrees of inherited hypopituitarism.[26][27] These transcription factors are responsible for organogenesis and early differentiation of pituicytes. Mutations in the PROP1 gene are the most common cause of familial and sporadic congenital pituitary hormone deficiencies.

hypothalamic disease

Unlike diseases that affect the pituitary directly, hypothalamic conditions can also diminish secretion of vasopressin and cause diabetes insipidus (DI). Typically, pituitary lesions alone do not cause DI, because some vasopressin-producing neurons terminate in the median eminence. Mass lesions such as craniopharyngiomas, malignant tumors, and metastasis; hypothalamic radiation; and infiltrative lesions such as sarcoidosis and more commonly Langerhans cell histiocytosis X have been associated with the development of DI.

weak

inflammatory disorders

May clinically and radiologically mimic pituitary adenomas with mass effect leading to headaches, visual impairment, and variable degrees of hypopituitarism.

Lymphocytic hypophysitis commonly results in adrenocorticotropic hormone and thyroid-stimulating hormone deficiency; however, diabetes insipidus and hyperprolactinemia have also been described. Hereditary hemochromatosis commonly results in gonadotropin deficiency.

severe postpartum hemorrhage (Sheehan syndrome)

During pregnancy, the pituitary gland enlarges due to hyperplasia and hypertrophy of the lactotroph cells, which produce prolactin. During a severe postpartum hemorrhage, the hypophyseal vessels, which supply the pituitary, constrict in response to decreasing blood volume, and subsequent vasospasm occurs leading to necrosis of the pituitary gland and hypopituitarism. The degree of necrosis correlates with the severity of the hemorrhage. Anterior pituitary hormone deficits may be single or multiple, depending on the degree of necrosis. Classically, it is associated with inability to lactate post delivery.[41]

empty sella syndrome

Empty sella refers to an enlarged sella turcica, which is not entirely filled with pituitary tissue. Primary empty sella is a defect in the diaphragm sella, which allows the cerebrospinal fluid (CSF) pressure to enlarge the sella and is typically not associated with hypopituitarism.[22]

In secondary empty sella, a mass such as an adenoma enlarges the sella and is later removed by surgery, radiation, or infarction and subsequently leaves a CSF vacuum. Most patients have no pituitary hormone dysfunction; however, hypopituitarism can result from mass effect of the adenoma, surgery, radiation, or infarction of the tumor.[42][43]

tuberculous meningitis

May cause hypopituitarism years after the original infection.

syphilis

May cause hypopituitarism in congenital syphilis and adult infection.

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