Read i bc27f85be50b71b1 Online
Authors: Unknown
670
AClITE CARE HANDBOOK FOR PHYSICAL TI-iERAPISTS
highly dependent on the diurnal rhythm of secretion. Normal serum levels
are 5-23 �gldl (8-10 AM) and 3-1 6 �gldl (4-6 I'M).21
•
Twenty-four-hour urinary corticosteroids. Analysis of urine
over a 24-hour period to determine the urinary levels of corticosteroids will provide a rough outline of cortisol output. Also indicated for diagnosing Cushing's or Addison's disease. Normal urine levels are 20-90 �gldl for a 24-hour period.22
•
ACTH levels are usually examined concomitantly with corti-
sol levels, as ACTH secretion from the pituitary gland is necessary for
cortisol secretion from the adrenal glands. Refer to Table 1 1-6 for
details on ACTH measurement.
Androgens
Individual androgen levels can be measured by RIA in the serum or by
metabolic products (17-ketosteroids) in the urine. I •• High concentrations of androgens may result in the following changes in women:
• Hirsutism, which is excessive hair growth in skin zones considered male in distribution (i.e., upper lip, side burns, chin, neck, chest, and lower abdomen)
• Amenorrhea, which is the absence of menstruation in women
older than 16 years of age or the absence of menses for longer than
6 months in women of childbearing age who previously had been
menstruating
• Voice change
• Increased muscle mass
Milleralocorticoids
Mineralocorticoids can be evaluated by testing serum electrolyte levels or plasma renin activity and aldosterone levels.11 Abnormalities of serum electrolyte levels, such as an increased potassium level, provide
a valuable screening tool for mineralocorticoid secretion disorders.
Aldosterone is the primary mineralocorticoid and is controlled by the
renin-angiotensin system. A rise in serum potassium and angiotensin
II results in aldosterone sectetion, which helps to balance Auid and
electrolyte levels. Blood samples of aldosterone are usually taken first
in the early morning, while the patient is still recumbent, and then
again after 4 hours of being awake and active. Normal serum levels of
ENDOCRINE SYSTEM
671
aldosterone range from 2 to 50 ngldl, depending on whether blood
was taken in the supine or upright position.4,5,1 J
Catecholamilles
Epinephrine and norepinephrine are commonly referred to as catecholamil/es, and their levels are generally measured through 24-hour urine samples. Dopamine, also a catecholamine, is the precursor for
epinephrine and norepinephrine and therefore can also be measured
to reflect rhe amount of carecholamines circulating in the body. However, the preferred screening tool is to measure the amount of catecholamine metabolites in the urine. The primary catecholamine metabolite is called val/illylmal1delic acid (VMA). Normal values for
these substances are as follows4,s:
Dopamine: 65-100 pg per 24 hours
Epinephrine: 1 .7-22.4 pg per 24 hours
Norepinephrine: 12. 1-85.5 pg per 24 hours
Vanillylmandelic acid: 1 .4-6.5 pg per 24 hours
Metabolic Tests
Metabolic tests are described in this section, as glucocorticoids (cortisol) affect carbohydrate, protein, and fat metabolism.
Glucose Toleral/ce Test
A glucose tolerance test was primarily used to diagnose diabetes mellitus; however, because of many confounding variables, it is currently not relied on to establish diabetes mellitus, but rather to help confirm
the diagnosis in certain cases. However, the glucose tolerance test is
the primary method of establishing the diagnosis of gestational diabetes mellirus.4.6
To perform the test, a 75- or 100-g glucose load is given to the
subject in the morning after a l O-hour fast. Blood glucose levels are
then measured at variable time periods, ranging from every half
hour to every hour for the next 2 to 5 hours after the glucose administration. The subject must remain inactive and refrain from smoking throughout the duration of the test. Normally, the blood glucose levels should fall back to baseline values after a 2-hour period. Normal glucose value for a fasting blood sugar (BS) is approximately 70-1 1 0 mgldl.'·4.6
672
ACUTE CARE HANDBOOK FOR PHYSICAL THERAPISTS
Adrenal Disorders
Adrenal Insufficiency
Autoimmune dysfunction can lead to destruction of the adrenal cortex (i.e., primary adrenal insuf(iciellcy Ot Addisoll's disease). Additionally, ACTH deficiency from the pituitaty gland can lead to atrophy of the adrenal cortex (secondary adrellal il1sllf(iciellcy). The
net result is an impaired adrenal system with decreased levels of glucocorticoids (cortisols), mineralocorticoids (aldosterone), and androgens. Given the systemic functions of these hormones, Addison's disease can have severe consequences if left untreated. Fortunately,
the incidence is rare.
Cortisol deficiency results in decreased gluconeogenesis (glucose
production), which in turn alters cellular metabolism. Decreased gluconeogenesis also results in hypoglycemia and decreased ability ro respond to stress. Aldosterone deficiency causes fluid and electrolyte
imbalance, primarily as a result of increased water excretion that
leads ro dehydration B."
The following are symproms and physical findings common ro
adrenal insufficiencyl.6.25:
• Weakness, fatigue
• Weight loss, nausea, vomiting, vague abdominal pain
• Muscle and joint pain
• Salt craving in fewer than 20% of patients
• Hyperpigmentation
• Hypotension
Management of adrenal insufficiency typically consists of pharmacologic intervention with any of the following steroids: hydrocortisone (Cortisol, Compound F), hydrocortisone acetate, prednisone (Deltasone), dexamethasone (Decadron, Dexasone), or fludrocortisone (Florinef) '·ls Caution muSt be taken, however, with corticosteroid administration, as corticosteroids can suppress the release of endogenous cortisol from the adrenal gland.2•
Pheochromocytoma
Pheochromocyroma is a rare adrenomcdullary disorder caused by a
rumor of the chromaffin cells in the adrenal medulla, which results in
excess secretion of the carecholamines, epinephrine, and norepineph-
ENDOCRINE SYSTEM
673
rinc. The occurrence is equal between men and women during their
twenties and thirties. Given the rare occurrence of this tumor, it often
goes undiagnosed. However, proper diagnosis is essential, as the sustained release of catecholamines can be life threatening. Early diagnosis generally has favorable results.6,25,27
Signs and symptoms of pheochromocytoma may include the
following 1.23.25.27:
• Hypertension (sustained or paroxysmal), palpitations, tachycardia, and orthostatic hypotension
• Headache, palpitations, and diaphoresis
• Excessive perspiration
•
crvousness and emotional outbursts or instability
• Elevated blood glucose levels and glucosuria
Management of pheochromocytoma generally consists of surgical
excision of the rumor with preoperative pharmacologic management
with one of the following medications: alpha-adrenergic blocking
agents (e.g., phenoxybenzamine [Dibenzyline], phentolamine [ Regitinel), beta-adrenergic blocking agents (e.g., propranolol [Inderal]), or tyrosine inhi bitors (alphamethlyparatyrosine).8.25.28
Pancreatic Disorders
Diabetes Mellitus
Diabetes mellitus is a syndrome with metabolic, vascular, and neural