Parathyroid Function Tests
Laboratory Tests
Blood tests to evaluate parathyroid function include serum parathormone (also known as parathyroid hormone; PH, PTH) levels, serum phosphate and calcium levels, urinary calcium, and serum alkaline phosphatase. Tests of other systems will also be ordered because normal calcium and phosphorus balance involves multiple body systems, including the musculoskeletal, gastrointestinal, and urinary systems.
Other Tests
Ultrasound, magnetic resonance imaging (MRI), thallium scan, and fine-needle biopsy can evaluate the function of the parathyroids and localize parathyroid cysts, tumors, and hyperplasia (abnormal increase in size).
Adrenal Function Tests
Laboratory Tests
Blood Tests. Common blood tests to determine adrenal function include the adrenocorticotropin hormone (ACTH) stimulation test, serum ACTH test, and plasma cortisol test. Plasma cortisol and ACTH follow a diurnal (daytime) pattern. They can be measured at 8 am and 4 pm to establish whether or not the normal diurnal pattern is present.
Urine Tests. Urine tests can also be used to evaluate adrenal function. Measurement of metabolites of catecholamines in the urine is useful in diagnosis. Urinary metanephrine is the most diagnostic urine test of adrenal medulla function. A 24-hour urine specimen may be collected for determining vanil-lylmandelic acid (VMA), a metabolite of catecholamines.
A clonidine suppression test can help determine pheochromocytoma, a catecholamine-secreting adrenal tumor. In this condition, serum and urinary catecholamines are elevated and are not suppressed by clonidine. (Normally, clonidine suppresses catecholamines.) Side effects of the test include hypotension, bradycardia, and somnolence (extreme sleepiness).
In addition, a somewhat risky test involves histamine administration, which produces a hypertensive crisis when the client has pheochromocytoma. Similarly, phen-tolamine (Regitine) can be given to provoke a hypotensive situation. The drop in blood pressure is diagnostic of pheochromocytoma.
A 24-hour urine specimen may be collected for determining metabolites such as 17-hydroxycorticosteroids, 17-ketosteroids, and 17-ketogenic steroids. These 24-hour urine collections require special preservatives. Know the institution’s requirements and make sure the appropriate container is available. Proper client education is necessary to ensure the collection of all urine.
Radiographic Evaluations
Radiographic evaluations of adrenal function include the adrenal angiogram and venogram, CT scan of the adrenals, MRI, ultrasonography, and retroperitoneal air sufflation, as well as an x-ray study of the sella turcica. These examinations detect benign and malignant tumors of the adrenal glands, as well as hyperplasia (excess multiplication of normal cells).
Adrenal Angiogram or Venogram. These tests involve insertion of a catheter and injection of a contrast medium (dye) so that x-ray contrast studies can be done. The client is usually NPO (nothing by mouth) before the test. The major complication is an allergic reaction to the dye. Therefore, be sure to determine the client’s allergy to dye before the test, and observe other precautions.To prevent this complication, propranolol (Inderal), diphenhydramine (Benadryl), or other medications may be administered for several days before and after the test. The test may also cause hemorrhage or dislodging of an atherosclerotic plaque from the wall of the blood vessel used for dye injection. This may cause an infarction. If hemorrhage occurs within the adrenal glands, Addison’s disease (chronic adrenocortical insufficiency resulting from adrenal gland destruction) may result. If surgery is needed later, it is more difficult when any of these events have occurred.
Angiograms and venograms are also contraindicated in clients who are pregnant, unstable, or uncooperative and in those with hemophilia, a bleeding disorder, or measurable atherosclerosis.
General Pancreatic Function Tests
The pancreas secretes two enzymes: amylase, necessary for carbohydrate metabolism; and lipase, necessary for fat digestion. Serum levels of both of these enzymes can be obtained. Elevations suggest pancreatitis. Urinary amylase levels also may be obtained. The amylase level in urine remains elevated for a longer time than it does in serum.
Tests for Diabetes Mellitus Blood Tests
A number of blood tests indicate the functioning of the endocrine portion of the pancreas. Some of these tests specifically relate to the detection and evaluation of diabetes mellitus.
Fasting Plasma Glucose. The fasting plasma glucose (FPG) test, formerly called the fasting blood glucose (also referred to as blood sugar), is used for diabetes screening. In most cases, an elevated fasting (without eating) or nonfasting blood glucose level is an indication of diabetes mellitus (metabolic condition involving elevated levels of glucose in the blood). The FPG level is defined as the amount of glucose (sugar) present in the blood when the client has been fasting for the prescribed length of time (6 to 8 hours). The normal for FPG ranges about 65 to 115 mg/dL. An FPG greater than or equal to 126 mg/dL and confirmed on a subsequent day indicates diabetes.
Oral Glucose Tolerance Test. The oral glucose tolerance test (OGTT) is a timed test used to confirm the diagnosis of diabetes mellitus when the client’s FPG is equal to or greater than 126 mg/dL, or when the client’s FPG is above normal, but below the diagnostic level for diabetes. It is also used in screening for gestational diabetes in both the 1- and 3-hour formats. OGTT also can diagnose functional hypoglycemia (abnormally low blood glucose).
• The client should ingest at least 150 grams of carbohydrate daily for 3 days before the test (most individuals following a good general diet easily meet this criterion).
• Tests of both blood and urine are done during the fasting state.
• The client drinks 75 to 100 grams of glucose. He or she must consume this glucose completely and as quickly as possible. Rationale: The starting point of this timed test must be as precise as possible.
• Blood and urine specimens are again taken at prescribed intervals: 1/2 hour, 1 hour, 2 hours, and 3 hours. Specimen collection is timed from the point of ingestion of glucose.
• The test begins with an empty bladder, although the pretest urine specimen is also saved as one of the fasting specimens to be examined.
• The laboratory technician takes the blood and urine specimens, labels them, and indicates the time when each was collected.
• The client may have water to drink during the test to provide comfort and to make voiding easier. Juice, other fluids, and food are not permitted.
• The client is not allowed to smoke or chew gum.
Normally, plasma glucose levels peak at 140 to 180 mL within 30 minutes to 1 hour after administration of an oral glucose solution, and return to fasting levels or lower within 2 to 3 hours. Urine glucose tests should remain negative throughout. Values greater than or equal to 120 to 200 mg/dL at 2 hours (2-hour postload glucose [2-h PG]) suggest diabetes. (Actual blood glucose tolerance levels may differ per laboratory.) Some factors that may affect the test include thiazide diuretics, oral contraceptives, lithium, caffeine, and nicotinic acid. These substances elevate glucose levels.
Glycosylated Hemoglobin. The glycosylated hemoglobin (HA 1C, HA|C, HbA|C) level reflects the client’s average blood glucose level over the previous 6 to 10 weeks. It is measured by determining the amount of glucose attached to a certain portion of hemoglobin in red blood cells. This test is invaluable in monitoring blood glucose control and allows the client and healthcare team to set measurable goals. Although normal ranges vary depending on the laboratory, most physicians want their clients to be in the range of 5% to 7%, depending on which exact subfactors they are measuring.
Estimated Average Glucose. Estimated average glucose (eAG) reports HA1C levels using the same units as standard hand-held glucose monitors. For example, if the HA1C is 7%, the eAG will be about 154 mg/dl.
Glycemic Index. The glycemic index (GI) is a measurement of how foods containing carbohydrates (starchy foods such as potatoes, bread, or cereals) raise blood glucose levels. Carbohydrates are compared with a standard known carbohydrate, such as glucose or white bread. Some foods are known to raise the blood glucose levels significantly and are considered to have a high GI. Carbohydrate-containing foods can be rated as a high GI, medium GI, or low GI. The use of the GI can assist with stabilization of meal planning and blood glucose levels.
Urine Tests
Normal urine is free from sugar (glucose), acetone, and protein, but any of these may be present in a diabetic person’s urine. Excess glucose in the blood spills over into the urine; acetone appears as a by-product of faulty metabolism. With the availability of a variety of sophisticated (but easy-to-use) blood glucose monitors, urine testing is now done infrequently, both in the healthcare facility and at home. The most common need for urine testing is the test for ketones if a client’s blood glucose level is consistently high. Because only clients with type 1 diabetes are susceptible to diabetic ketoacidosis, these clients learn to test their urine for ketones if their blood glucose readings exceed 240 mg/dL.
Nursing Alert The test for urine ketones (acetone) is especially important if the client is vomiting, has a fever; or has a high concentration of glucose in the blood (>240 mg/dL).
Keto-Diastix Test. Acetone is a ketone body that is present when the body cells are starving because of faulty metabolism. Buildup of acetone leads to ketosis, which in turn leads to acidosis. Vomiting or excessive perspiration can alter electrolyte balance. The Keto-Diastix test, which detects both elevated glucose and ketone levels in urine, is typically done in the laboratory but can be done by healthcare providers using standardized urine dip sticks.
NCLEX Alert Laboratory test results are commonly seen in nursing situations. NCLEX clinical scenarios might require knowledge of normal levels of many tests, including blood glucose, thyroid functioning, or hormone levels. Nursing reactions to abnormal levels (e.g., low or high blood glucose) are significant concerns.
COMMON MEDICAL AND SURGICAL TREATMENTS
The most common surgical treatment for some pituitary or thyroid disorders is removal of the affected gland. The pituitary gland also may be removed in some cases to slow or stop the spread of certain types of malignancies that are nourished by an endocrine hormone.
Diabetes mellitus cannot be treated with surgery, although pancreatic or cellular transplants have had some success in reversing the symptoms.
NURSING PROCESS
DATA COLLECTION
Using the skills of physical examination and nursing assessment and data gathering, observe and document client status for possible endocrine disorders. This establishes a baseline for future comparison and helps determine the presence of suspected endocrine-related complications. Report any changes in baseline levels.
Much knowledge of endocrine function is based on laboratory examination of blood. Other testing (e.g., x-rays or ultrasound) is also done. Check reports of these evaluations and report any abnormal results immediately. Nurses may perform blood testing for glucose and occasionally urine testing for ketones.
While caring for clients, note any signs and symptoms of endocrine disorders and report them. In addition, observe the client’s emotional response to the disorder or disease. Does the client need assistance to meet daily needs? Is the client anxious or fearful of the outcome? Is the client having difficulty accepting a disorder’s long-term nature?
PLANNING AND IMPLEMENTATION
Plan together with the healthcare team for effective care to meet the client’s needs, based on the nursing diagnoses. Properly prepare clients for diagnostic tests. Provide preoperative and postoperative care for clients undergoing surgery.
Because disorders of the endocrine system can affect most body functions, listing all the nursing implications is difficult. An endocrine disorder can be a simple imbalance that is successfully rectified by administration of hormones or other medications. However, in some cases, such as endstage renal disease caused by diabetes mellitus, a client may require total nursing care and assistance to meet all needs, including those related to death and dying.
Clients may have difficulty accepting an endocrine disorder’s chronic nature and the fact that treatments, such as insulin injections or thyroid medications, must continue for life. Most clients need to learn about their disorder, its prognosis, and its treatment.
EVALUATION
Periodically, the healthcare team evaluates the outcomes of the client’s care. Have short-term goals been met? For example, is the client’s blood glucose level being maintained within an acceptable range? Are long-term goals still realistic? Planning for further nursing care considers the client’s prognosis, any complications, and the client’s response to care given. Client and family teaching is an important component of nursing care. Do the client and family understand the treatment required and the underlying reasons? For example, do they demonstrate an understanding of the need for lifelong thyroid hormonal replacement? Is teaching adequate and documented?
PITUITARY GLAND DISORDERS
Disorders of the Anterior Lobe
The anterior pituitary exerts control by a negative feedback system—after it has stimulated a target gland to produce a hormone and the hormone level rises sufficiently high, the anterior pituitary stops stimulating the target gland and stops the hormone release. The anterior lobe alone produces or releases the following hormones: growth hormone (GH; somatotropin [STH]), ACTH, TSH, prolactin, follicle-stimulating hormone (FSH), and luteinizing hormone (LH). These hormones are of vital importance in growth, maturation, and reproduction.
Gigantism and Acromegaly
Disturbances of the anterior lobe may cause overproduction of the growth hormone STH. If overproduction occurs in childhood, it causes excessive growth of bones, or gigantism. In adults, an excess of STH causes overgrowth of tissues, called acromegaly. The features of the person with acromegaly coarsen. He or she develops a massive lower jaw, thick lips, a bulbous nose, a bulging forehead, and hands and feet that seem enormous. In women, facial hair also appears (hirsutism) and the voice deepens. Headaches are common and partial vision loss may develop. The spleen, heart, and liver enlarge; muscles weaken; and joint pain and stiffness appear. Men may be impotent. Women may not menstruate (amenorrhea).
Acromegaly is treated by irradiation of the pituitary gland using proton-beam therapy or surgical intervention. Recently, certain drugs, such as bromocriptine mesylate (Parlodel) and somatostatin analogs, have shown promise in lowering the levels of STH. Treatment can stop the disease’s progression, but therapy cannot alter abnormal growth that has already occurred.
Disorders of the Posterior Lobe
The posterior lobe of the pituitary secretes and releases hormones that affect blood pressure and control water balance in the kidney tubules. It releases antidiuretic hormone (ADH or vasopressin), which regulates the passage of water through the kidneys. It also releases oxytocin in women, which stimulates uterine contractions during labor, and milk release during breastfeeding.
Syndrome of Inappropriate Antidiuretic Hormone (SIADH)
The syndrome of inappropriate antidiuretic hormone (SIADH) involves the excessive secretion of ADH. Clients with SIADH cannot excrete dilute urine. Fluid retention and ultimately water intoxication occur, along with sodium deficiency. SIADH can result from central nervous system (CNS) disorders, chemotherapy, ADH production by some cancers, and overuse of vasopressin therapy.
Urinary output decreases. The severity of the condition depends on how low the client’s serum sodium levels fall (hyponatremia) and how much water he or she retains. The client may complain of a headache or experience confusion, lethargy, seizures, and possibly coma if sodium deficiency is severe. Hyponatremia may cause diarrhea. Weight gain also occurs with fluid retention.
Close monitoring of fluid intake and output (I&O), daily weights, and mental status is necessary. Institute safety measures to reduce the risk of possible injury. Fluids usually are restricted to 500 to 1,000 mL daily. To correct fluid retention and hyponatremia, medications such as hypertonic saline infusions and diuretics may be ordered. Also, medications such as demeclocycline (Declomycin) and lithium carbonate, which interfere with the antidiuretic action of ADH, may be ordered. Treatment is aimed at correcting the underlying problem.
Diabetes Insipidus
Diabetes insipidus is a disease that results from underproduction of ADH. Primary nephrogenic insipidus is rare and is caused by kidney dysfunction due to a deficiency in ADH or to a lesion in the midbrain. Secondary central diabetes insipidus results from a tumor in the gland itself or pressure in the pituitary area from head trauma, infection, or other tumors. It may also occur after pituitary surgery that removes all or a portion of the gland.
In diabetes insipidus, the client voids copious amounts of urine, as much as 15 to 20 L in 24 hours. The urine is dilute, with a specific gravity less than 1.006, and contains no sugar or acetone. The client is constantly thirsty; restricting fluids may have some effect. Keep accurate I&O records to make sure the volume of output is being replaced; closely monitor electrolyte levels. Record daily weights in the early morning before breakfast. Despite an abnormally large appetite, the client is weak and may need assistance with self-care. Treatment consists of giving ADH (vasopressin [Pitressin] subcutaneously, intramuscularly, or by nasal spray) to control urinary output.
Nursing Alert Monitor Pitressin administration closely because it can cause coronary artery constriction.
Pituitary Neoplasms
Neoplasms of the pituitary gland can affect various aspects of body function. An overgrowth of eosinophilic cells in the pituitary can result in gigantism. A basophilic tumor in the pituitary can upset production of the hormone that regulates the adrenal glands, leading to hyperadrenalism (Cushing’s syndrome). A chromophobic tumor can destroy the pituitary and result in hypopituitarism. A client with this disorder has fine, scanty hair; lowered basal metabolic rate; lowered body temperature; and a tendency toward obesity and slow movements.
Hypophysectomy
Hypophysectomy, surgical removal of the pituitary gland, may be done for a variety of reasons, including malignancy or to decrease diabetic retinopathy. Occasionally the pituitary is removed to control pain associated with metastatic carcinoma of the breast or prostate. The client usually is admitted to the intensive care unit after surgery.
