1212 SECTION 10 Problems Related to Regulatory and Reproductive Mechanisms

DIAGNOSTIC STUDIES OF ENDOCRINE SYSTEM

Accurately performed laboratory tests and radiologic examina-tions contribute to the diagnosis of an endocrine problem. Lab-oratory tests usually involve blood and urine testing. Ultrasound may be used as a screening tool to localize endocrine growths such as thyroid nodules. Radiologic tests include regular x-ray, computed tomography (CT), and magnetic resonance imaging (MRI). With all diagnostic testing, you are responsible for explaining the procedure to the patient and caregiver. Diagnos-tic studies common to the endocrine system are presented in Table 48-8.

Laboratory StudiesLaboratory studies used to diagnose endocrine problems may include direct measurement of the hormone level, or they may involve an indirect indication of gland function by evaluat-ing blood or urine components affected by the hormone (e.g., electrolytes).

Hormones with fairly constant basal levels (e.g., T4) require only a single measurement. Notation of sample time on the laboratory slip and sample is important for hormones with cir-cadian or sleep-related secretion (e.g., cortisol). Evaluation of other hormones may require multiple blood samplings such as in suppression tests (e.g., dexamethasone) and stimulation tests

FINDING DESCRIPTION POSSIBLE ETIOLOGY AND SIGNIFICANCECardiovascularChest pain Angina caused by increased metabolic demands HyperthyroidismDysrhythmias Tachycardia, atrial fibrillation Hypothyroidism, hyperthyroidism, pheochromocytomaHypertension Elevated blood pressure caused by increased

metabolic demands and catecholaminesHyperthyroidism, pheochromocytoma, Cushing syndrome

MusculoskeletalChanges in muscular

strength or muscle massGeneralized weakness and/or fatigue Common symptoms associated with many endocrine problems,

including pituitary, thyroid, parathyroid, and adrenal dysfunctions; diabetes mellitus; diabetes insipidus

Decreased muscle mass Specifically seen in those with growth hormone deficiency and in Cushing syndrome secondary to protein wasting

Enlargement of bones and cartilage

Coarsening of facial features; increases in size of hands and feet over a period of several years

Gradual enlargement and thickening of bony tissue occurs with growth hormone excess in adults as seen in acromegaly

NutritionChanges in weight Weight loss Hyperthyroidism caused by increases in metabolism, diabetic

ketoacidosisAltered glucose levels Weight gain Hypothyroidism, Cushing syndrome

Increased serum glucose Diabetes mellitus, Cushing syndrome, growth hormone excess

NeurologicLethargy State of mental sluggishness or somnolence HypothyroidismTetany Intermittent involuntary muscle spasms usually

involving the extremitiesSevere calcium deficiency that can occur with hypoparathyroidism

Seizure Sudden involuntary contraction of muscles Consequence of a pituitary tumor; fluid and electrolyte imbalance associated with excessive ADH secretion; complications of diabetes mellitus; severe hypothyroidism

Increased deep tendon reflexes

Hyperreflexia Hyperthyroidism, hypoparathyroidism

GastrointestinalConstipation Passage of infrequent hard stools Hypothyroidism; hyperparathyroidism caused by calcium

imbalances

ReproductiveChanges in reproductive

functionMenstrual irregularities, decreased libido,

decreased fertility, impotenceReproductive function is significantly affected by various endocrine

abnormalities, including pituitary hypofunction, growth hormone excess, thyroid dysfunction, and adrenocortical dysfunction

OtherPolyuria Excessive urinary output Diabetes mellitus (secondary to hyperglycemia) or diabetes

insipidus (associated with decreased ADH)Polydipsia Excessive thirst Extreme water losses in diabetes mellitus (with severe

hyperglycemia) and diabetes insipidus, dehydrationDecreased urine output ADH leads to reabsorption of water from kidney

tubulesSyndrome of inappropriate antidiuretic hormone (SIADH)

Thermoregulation Cold insensitivity Hypothyroidism caused by a slowing of metabolic processesHeat intolerance Hyperthyroidism caused by excessive metabolism

ADH, Antidiuretic hormone.

TABLE 48-7 COMMON ASSESSMENT ABNORMALITIEScontdEndocrine System