Read i bc27f85be50b71b1 Online
Authors: Unknown
vasopressin)
Water deprivation test (dehydration [est or concentration
test). Indicated for diagnosing diabetes insipidus (01).
Normally, if water is withheld, ADH levels rise to help
increase water reabsorption in the kidneys. During the
test, the patient is deprived of Au ids, and serial measurements of urine osmolality are taken. Normally,
ADH secretion causes a change in urine osmolality, but
E.NDOCRINE. SYSTEM
663
Hormone(s)
Test Description
with 01, the osmolality remains unchanged. While
the patient is being deprived of water, vasopressin
may be administered to help delineate whether the
DI is caused by piruitary or renal dysfunction.
Water loading test. Indicated for diagnosing syndrome
of inappropriate anridiureric hormone (SIADH).
During the tesr, the patienr ingests 20-25 mUkg of
fluid, with hourly serum and urine osmolaliry levels
being measured for 4 hrs. Normally, with water
ingesrion, the plasma and urine osmolality should
decrease, and urine output should increase. With
SIADH, there is little or no change in these values.
Source: Data from LM Malarkey, ME McMorrow (cds). Nurse's Manual of Laboratory
Tes[s .and Diagnostic Procedures. Philadelphia: Saunders, 2000;580-584, 552-555,
613-614,616-619.
Pih,itary Disorders
Dysfunction of the pituitary-hypothalamic system generally results
from hyper- or hyposecretion of tropic hormones. Hypersecretion of
pituitary hormones (hyperpituitarism) is most commonly due to benign
anterior pituitary tumors. Hyposecretion of pituitary hormones (pituitary insufficiency) can result from pituitary disease, diseases affecting the hypothalamus or surrounding structures, or disturbance of blood
Aow around the hypothalamus and pituitary.'2,13
Hyperpituitarism
The overproduction of the pituirary hormones GH, ACTH, and
antidiuretic hormone (ADH) is discussed below.
Growth Hormone Ouerproductioll
The most common presentation of excessive GH secretion is acromegaly in adults or gigantism in children. Excessive GH secretion has been linked primarily to anterior pituitary adenomas and not necessarily from excessive hypothalamic stimulation of the pituitary.13
Signs and symptoms of acromegaly include the following1•13:
• Enlargement of hands and feet, coarse facial features with furrowed brows
• Oligomenorrhea or amenorrhea in women
664
AClITE CARE HANDBOOK FOR PHYSICAL THERAPISTS
• Paresthesia of hands, carpal tunnel syndrome
• Sweating
• Headaches
• lmpotence in men
• Diabetes mellitus
•
Hypertension
•
Joint pains, osteoarthritis
Management of acromegaly may consist of the following:
transphenoid surgical resection of anterior pituitary adenoma (treatment of choice), GH suppression with somatostatin and its analogs (octreotide), or with dopamine agonists and external irradiation as a
last resorr.14
Clinical Tip
Given the multisystem effects in patients with acromegaly, activity progression should proceed cautiously,
with a focus on energy conservation and joint protection techniques.
Adrenocorticotropic Hormone Overproduction
An increase in ACTH production by the pituitary gland results in
increased levels of serum cortisol, which is a glucocorticoid secreted
by the adrenal glands. Glucocorticoids are involved with carbohydrate, protein, and fat metabolism; therefore, excess cortisol levels affect these cellular processes. Any clinical syndrome that results in
glucocorticoid excess is called Cushing's syndrome. Cushillg's disease,
however, is specific to pituitary lesions that cause bilateral adrenal
hyperplasia and is not discussed in this chapter.' Pituitary hypersecretion of ACTH occurs in approximately 70% of the patients with Cushing's syndrome. The hypersecretion of ACTH is mainly from
pituitary adenomas or microadenomas.6
Signs and symptoms of Cushing's syndrome include the following"., '.13:
• Truncal obesity with thin extremities
•
Redness and rounding of the face (moon face)
ENDOCRINE SYSTEM
665
• Easy bruising, thinning of the skin, and presence of striae and
darker pigmentation
• Hirsutism, oligomenorrhea, or amenorrhea
• Hypertension
• Osteoporosis (radiographically confirmed)
• Proximal muscle weakness
• Backache
• Glucose intolerance
Management of Cushing's syndrome may consist of any of the following: surgical resection of pituitary lesion, radiation or chemotherapy for the lesion, or medical management with steroidogenic inhibitors (ketoconazole, mitotane, etomidate, metyrapone, and aminoglutethimide) or neuromodulators of ACfH release (valproic acid, bromocriptine, and cyproheptadine). Surgical resection of the adrenal
glands is a last-resort measure.14
Clinical Tip
Management of weakness, myopathy, pain, edema, and
osteoporosis should be the focus of physical therapy intervention and be complementary to the medical management of the patient. Blood pressure changes during activity should be monitored, given the possibility of hypertension.
Caution should also be taken to avoid bruising during
mobility. Refer to Diabetes Mellitus for further activity
considerations.
Antidiuretic Hormone Overproduction
The syndrome of inappropriate secretion of ADH (SIADH) is a condition of fluid and electrolyte imbalance resulting in hyponatremia (reduced sodium levels) from excessive water reabsorption. In this
condition, ADH is secreted from the posterior pituitary when it
should be inhibited.