Patients with hypothalamic-pituitary lesions generally present with some combination of
Symptoms and signs of a mass lesion: headaches, altered appetite, thirst, visual field defects—particularly bitemporal hemianopia or the hemifield slide phenomenon (images drifting apart)
Imaging evidence of a mass lesion as an incidental finding
Hypersecretion or hyposecretion of one or more pituitary hormones
The most common cause of hypopituitary or hyperpituitary secretion is a pituitary or hypothalamic tumor. A tumor tends to produce an enlarged sella (sella turcica). Alternatively, an enlarged sella may represent empty sella syndrome.
(Pituitary structure and function and relationships between the hypothalamus and the pituitary gland are discussed in Overview of the Endocrine System Overview of the Endocrine System The endocrine system coordinates functioning between different organs through hormones, which are chemicals released into the bloodstream from specific types of cells within endocrine (ductless)... read more .)
Empty sella syndrome
In this disorder, the sella appears empty because it is filled with cerebrospinal fluid, which flattens the pituitary gland against the wall of the sella. The syndrome may be
Secondary to injury (eg, ischemia after childbirth, surgery, head trauma, radiation therapy)
The typical patient is female (> 80%), obese (about 75%), and hypertensive (30%) and may have idiopathic intracranial hypertension Idiopathic Intracranial Hypertension Idiopathic intracranial hypertension causes increased intracranial pressure without a mass lesion or hydrocephalus, probably by obstructing venous drainage; cerebrospinal fluid composition is... read more (10%) or spinal fluid rhinorrhea (10%).
Pituitary function in patients with empty sella syndrome is frequently normal. However, hypopituitarism Generalized Hypopituitarism Generalized hypopituitarism refers to endocrine deficiency syndromes due to partial or complete loss of anterior lobe pituitary function. Various clinical features occur depending on the specific... read more may occur, as may headaches and visual field defects. Occasionally, patients have small coexisting pituitary tumors that secrete growth hormone (GH), prolactin, or adrenocorticotropic hormone (ACTH).
Diagnosis can be confirmed by CT or MRI.
No specific therapy is needed for an empty sella alone.
Anterior lobe lesions
Hypersecretion of anterior lobe hormones (hyperpituitarism) is almost always selective, although occasionally a tumor hypersecretes both growth hormone and prolactin. The anterior pituitary hormones most commonly secreted in excess are GH (as in acromegaly Gigantism and Acromegaly Gigantism and acromegaly are syndromes of excessive secretion of growth hormone (hypersomatotropism) that are nearly always due to a pituitary adenoma. Before closure of the epiphyses, the result... read more , gigantism Gigantism and Acromegaly Gigantism and acromegaly are syndromes of excessive secretion of growth hormone (hypersomatotropism) that are nearly always due to a pituitary adenoma. Before closure of the epiphyses, the result... read more ), prolactin (as in galactorrhea Prolactinoma Prolactinomas are noncancerous tumors made up from lactotrophs in the pituitary gland. The most common symptom of a prolactinoma is galactorrhea. Diagnosis is by measurement of prolactin levels... read more ), and ACTH (resulting in Cushing disease Cushing Syndrome Cushing syndrome is a constellation of clinical abnormalities caused by chronic high blood levels of cortisol or related corticosteroids. Cushing disease is Cushing syndrome that results from... read more ).
Hyposecretion of anterior lobe hormones (hypopituitarism Generalized Hypopituitarism Generalized hypopituitarism refers to endocrine deficiency syndromes due to partial or complete loss of anterior lobe pituitary function. Various clinical features occur depending on the specific... read more ) may be generalized, usually due to a pituitary tumor, or is idiopathic or may involve the selective loss of one or a few pituitary hormones.
Posterior lobe lesions
The 2 posterior lobe hormones are
Vasopressin (antidiuretic hormone [ADH])
In women, oxytocin causes myoepithelial cells of the breast and myometrial cells of the uterus to contract. Oxytocin is present in men but has no proven function.
Deficiency of vasopressin results in arginine vasopressin deficiency (central diabetes insipidus) ArginineVasopressin Deficiency (Central Diabetes Insipidus) Arginine vasopressin deficiency (central diabetes insipidus) results from a deficiency of vasopressin (antidiuretic hormone [ADH]) due to a hypothalamic-pituitary disorder. Polyuria and polydipsia... read more . Excess vasopressin secretion results in the syndrome of inappropriate ADH secretion Syndrome of inappropriate antidiuretic hormone secretion (SIADH) Hyponatremia is decrease in serum sodium concentration < 136 mEq/L (< 136 mmol/L) caused by an excess of water relative to solute. Common causes include diuretic use, diarrhea, heart failure... read more (SIADH).
Drugs Mentioned In This Article
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|Arginine, Nutricia SHS L-Arginine, R-Gene|