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Guided Lecture Notes, Chapter 43, Patient Assessment: Endocrine System
Learning Objective 1. Analyze the relationship between dysfunction of the
hypothalamus and the pituitary gland and the signs and symptoms of the resultant
disorder.

Explain that endocrine disorders can affect all body systems and are usually
caused by the overproduction or underproduction of hormones.

Refer to Box 43-1 for summary of the approach used to assess a patient
suspected of having an acute endocrine disorder.

Refer to PowerPoint slide 5 and explain that because the primary function of
ADH is to control water excretion by the kidney, attention must be focused on
the patient’s hydration status (manifests as fluid volume excess or deficit) and
serum and urine osmolality to acquire information about the general
functioning of this part of the pituitary.

PowerPoint slide 6 lists focused assessment for patients with endocrine
disorder.

Refer to Box 43-1 for specific parameters included in the endocrine health
history.

Discuss that assessment of hydration status includes skin turgor, buccal
membrane moisture, vital signs, and weight.

Explain that a patient with hypovolemia (as seen in diabetes insipidus) would
experience weight loss from excretion of large volumes of dilute urine and
would experience tachycardia, hypotension, poor skin turgor, dry buccal
membranes, and cognitive changes associated with dehydration and
hypernatremia.

Explain that a patient with hypervolemia (as seen in SIADH) would display
signs of water intoxication, such as edema, scant urinary output, weight gain
(1 liter of fluid equals 2.2 pounds of weight), hypertension, moist buccal
membranes, good skin turgor, and cognitive changes associated with
hyponatremia.

Strict measuring of intake and output is necessary to assess hydration status.

Urine specific gravity is measured routinely, noting the nature of the urine
(color, concentration, and volume).

Advanced monitoring techniques may be necessary, such as central venous
pressure or hemodynamic monitoring with a pulmonary artery catheter.

Laboratory studies
o The normal serum ADH level is 1 to 13.3 pg/mL; refer to Table 43-2 to
compare and contrast laboratory values for diabetes insipidus and
SIADH.
o Specific gravity reflects the kidneys’ ability to dilute and concentrate
urine. Normal ranges from 1.010 to 1.025.
o Serum osmolality ranges from 270 to 300 mOsm/kg and measures the
concentration of diluted particles in the bloodstream.
o Urine osmolality is a more exact measure of urine concentration and is
a more useful test when performed in conjunction with serum
osmolality. The normal range is 300 to 900 mOsm/kg/24 h and 50 to
1,200 mOsm/kg in a random sample.
o Water deprivation or test water restriction is not useful in critically ill.
o Antidiuretic hormone administration—exogenous ADH (vasopressin or
Pitressin) given subcutaneously. In nephrogenic diabetes insipidus, the
person does not demonstrate a reaction to exogenous ADH because
the kidney receptors in the collecting duct are unresponsive to ADH.
People with central diabetes insipidus respond readily to the
exogenous ADH.

Diagnostic studies
o Discuss that CT and MRI are essential in diagnosing primary diseases
affecting the area of the brain; for example, disorders that affect the
pituitary–hypothalamic axis are brain tumors, aneurysms, edema from
surgical exploration or traumatic injuries, and necrotic lesions.
o Angiography assists with precise viewing of the vascular supply in the
area. PowerPoint slide 8 provides examples of MRI and CT scans of
a pituitary tumor.
Leaning Objective 2. Compare and contrast the signs and symptoms of
hypothyroidism and hyperthyroidism.
 PowerPoint slide 10 discusses the thyroid gland. Explain the negative
feedback system illustrated on PowerPoint slide 13.
 Explain that hyperthyroidism can lead to an extreme form of thyrotoxicosis,
which is life-threatening.
 Explain that hypothyroidism can result in a severe hypometabolic state and if
untreated, myxedema coma can develop.
 Explain that a detailed history is needed to uncover signs and symptoms of
either hypothyroidism or hyperthyroidism.
 PowerPoint slide 15 compares and contrasts the two disorders.
 Refer to Box 43-3 for a detailed description of the steps for palpating the
thyroid gland.
 Explain that a bruit is caused by excessive or turbulent blood flow associated
with hyperthyroidism and the resultant hypermetabolic state.
 Discuss that hypothyroidism is frequently associated with hypotension,
bradycardia, hypoventilation, and subnormal temperature; dry, flaky skin;
edema over the pretibial area; and a deep or husky voice; slowed cognitive
functioning with slower-than-normal verbal responses, slowed rapid
alternating movements, and decreased deep tendon reflexes.
 Discuss that patients with hyperthyroidism have more neurological
manifestations, such as tremor, nervousness, insomnia and restless
movements, and hyperactive reflexes; hypertension, tachycardia, tachypnea,
and hyperthermia; goiter with detectible bruit; and exophthalmos or proptosis
of the eyes.
 Laboratory studies; refer to Table 43-3 for common thyroid tests.
o The TSH test is used to diagnose hypothyroidism and hyperthyroidism
and measures circulating TSH from the anterior pituitary.
o A high TSH level helps diagnose primary hypothyroidism; normal adult
value for TSH is 0.4 to 5.4 mIU/L.
o Total T4 measures both the free T4 and the portion carried by
thyroxine-binding globulin (TBG). T4 is increased in hyperthyroidism
and decreased in hypothyroidism.
o Free T4 and free T4 index measure the free part of T4, the part that is
not bound to protein.
o Free T3 measures the circulating T3 that exists in the free state in the
blood, unbound to protein. This is one measure to evaluate thyroid
function. T3 is about five times more potent than T4 and is more
metabolically active. Decreased values indicate hypothyroidism.
Radioisotopes also affect results. Normal adult values are 260 to 480
pg/dL.
o The T3 resin uptake test is an indirect measure of TBG available to
bind T3 and T4. It is increased with thyrotoxicosis.
o Calcitonin, or thyrocalcitonin, is a hormone secreted by the thyroid. It is
secreted in response to high levels of calcium and reduces the
calcium level by increasing its deposition in bone.
o Thyroid antibodies—several autoimmune thyroid diseases produce
detectable antibodies. Specifically, Graves’ disease, Hashimoto’s
thyroiditis, and chronic autoimmune thyroid disease cause elevations
in antithyroid antibodies, detectable by immunoassay techniques.
These conditions can lead to severe hypothyroidism or
hyperthyroidism if not treated.
o Thyroglobulin can be measured by radioimmunoassay and is elevated
in most thyroid disorders. It is used clinically to follow the progression
of disease in a patient being treated for thyroid cancer.
 Discuss the various diagnostic studies for thyroid dysfunction.
o The radioactive iodine uptake test measures the rate of iodine uptake
by the thyroid gland after the administration of iodine-123 tracer (by
capsule, solution, or intravenous injection). Normally, the radioactive
iodine is evenly distributed in the thyroid gland, and the scan shows a
normal size, position, and shape.
o The thyroid scan may be performed in conjunction with a radioactive
iodine uptake study. These nuclear tests can indicate areas of
increased and decreased function and provide data to diagnose
hyperthyroidism.
o Fine-needle biopsy is the diagnostic tool of choice for detecting
malignancy for a thyroid nodule. It is often the initial test for evaluation
of any thyroid mass.
o Ultrasound of the thyroid gland produces good images of structures
and can detect masses, nodules, cysts, and enlargements of the
gland.
 Discuss the parathyroid gland using PowerPoint slide 18 to guide.
 Explain that overproduction of PTH results in hyperparathyroidism and is
characterized by bone decalcification and the development of renal stones
containing calcium.
 Hypocalcemia, as a result of hypoparathyroidism, manifests neurologically as
tetany (general muscular hypertonia, tremor, and spasmodic movements)
when calcium levels dip below 5 to 6 mg/dL. The patient may complain of
numbness, tingling, and cramps in the extremities. As the hypocalcemia
worsens, the patient experiences bronchospasm, laryngeal spasm,
carpopedal spasm (flexion of the elbows and wrists with extension of the
carpophalangeal joints), dysphagia, photophobia, cardiac dysrhythmias, and
seizures.
Learning Objective 3. Formulate a plan for collecting history and physical examination
data focusing on endocrine function.
 Explain that the nurse establishes a history of electrolyte imbalance,
specifically related to calcium and phosphorus.
 Refer to Box 43-1 for components of the endocrine health history.
 Explain that the patient may present with kidney stone symptoms, such as
severe flank pain, groin pain, frequent urination, hematuria, and nausea and
vomiting. The patient may experience joint and bone pains and may sustain
pathological fractures, especially of the spine. The nurse remains vigilant for
signs of tetany and related complications.
 Refer to Figure 43-5 for illustration of Trousseau’s sign or Chvostek’s sign.
 Discuss laboratory studies.
o Normal calcium levels range from 8.6 to 10.3 mg/dL. Most (99%) of body
calcium is in the bone, and the remaining 1% is in the ECF. Nearly 50% of
serum calcium is ionized or free, whereas the remainder is bound to
albumin.
o Marked serum calcium elevations (levels 10.3 mg/dL) are the most
obvious manifestation of hyperparathyroidism and common causes
include primary hyperparathyroidism, malignancy, sarcoidosis, vitamin D
toxicity, hyperthyroidism, and some medications, such as thiazide
diuretics and lithium.
o Low serum calcium levels are the marker for hypoparathyroidism. Tetany
develops at calcium levels of 5 to 6 mg/dL or lower. Common causes of
hypocalcemia include hypoalbuminemia, renal failure,
hypoparathyroidism, acute pancreatitis, tumor lysis syndrome, and severe
hypomagnesemia.
 Discuss that disorders of the endocrine pancreas are characterized by
chronic hyperglycemia and result in major shifts of fluids and electrolytes as
well as in blood glucose levels.
 Explain that a complete history is multisystem focused because glucose
dysfunction affects every system of the body. Refer to PowerPoint slide 25
for list of pertinent data; refer to Box 43-1 for a health history review of the
endocrine system.
 Physical examination focuses on the severe fluid and electrolyte and
neurological dysfunction seen with acute diabetes complications such as
DKA, HHS, and hypoglycemia. Figure 43-6 summarizes the physical
features seen in the patient with diabetes mellitus.
 Discuss pertinent laboratory studies.
 The fasting blood glucose level provides a foundation for managing diabetes
mellitus. The normal value for fasting glucose in adults is 65 to 110 mg/dL.
Two-hour postprandial blood glucose testing helps further evaluate
carbohydrate metabolism, and the normal value is 65 to 126 mg/dL.
 Discuss that the American Diabetes Association (ADA) criteria for the
diagnosis of diabetes are given in Box 43-6.
 Discuss drugs that interfere with glucose regulation, including corticosteroids,
diuretics, lithium, phenytoin, β-blockers, and estrogen. Hypoglycemic
reactions can result from sulfonylureas, insulin, alcohol, β-blockers,
angiotensin-converting enzyme inhibitors, and aspirin.
 Fingerstick glucose testing can be used at the bedside for immediate
feedback regarding the patient’s glucose status. In general, point-of-service
testing such as this may not be appropriate for the critically ill patient
because fingerstick testing requires adequate tissue perfusion for accuracy,
and many critically ill patients do not have this required level of perfusion.
Testing glucose from more direct sources of blood (ie, veins, venous lines,
central lines, arterial lines) may enhance accuracy.
 Glycosylated hemoglobin (HbA1c) testing offers information about the average
amount of serum glucose that is bound to hemoglobin for the 100- to 120day life span of erythrocytes. This information is now used to diagnose
diabetes and to assess data trends for a person who has been previously
diagnosed with diabetes (normal: 4% to 7%).
 Serum fructosamine level measures glycosylation of serum protein albumin. It
is a useful index that reflects chronic glycemic control in patients with
diabetes for whom HbA1C may be inaccurate, such as those with anemia or
hemoglobin abnormalities (eg, sickle cell disease).
 Insulin measures abnormal carbohydrate metabolism by measuring the
amount of circulating serum insulin in the fasting state. Insulin is released in
response to serum glucose levels. The normal adult value is 6 to 24
mcU/mL.
 C-peptide is a single chain of amino acids connecting A and B chains of
insulin in the proinsulin molecule. It has no known physiological function, but
because it persists in higher concentrations than insulin, it may be a more
accurate reflection of insulin levels. Normal values are 0.5 to 2.0 ng/mL and
indicate that the body is still producing some insulin.
 Glucagon controls the production, storage, and release of glucose. Normal
fasting values are 50 to 200 pg/mL.
 Serum ketones reveal information about the use of fat metabolism in lieu of
carbohydrates as seen in the critically ill person with diabetes. The normal
serum ketone level is 2 to 4 mg/dL.
 Urine ketones are not normally found in the urine. Ketones in the urine are
associated with diabetes and other diseases of altered carbohydrate
metabolism.
Learning Objective 4. Differentiate between normal and abnormal findings for an
adrenal gland disturbance.
 Discuss the function of the adrenal glands (refer to PowerPoint slide 30).
 Refer to Box 43-1 for a review of relevant health history questions related to
adrenal disorders.
 Refer to the summary of the clinical manifestations of adrenal cortical
insufficiency and glucocorticoid excess given in Table 43-5.
Learning Objective 5. Explain laboratory tests used to diagnose acute endocrine
disorders.
 Discuss pertinent laboratory values listed on PowerPoint slide 32.
 Explain that cortisol secretion is diurnal; it is normally higher in the early
morning (6:00 to 8:00 AM) and lower in the evening (4:00 to 6:00
PM).
This
variation is lost in patients with adrenal hyperfunction and in people under
stress. Serum samples are drawn between 6:00 and 8:00
AM
and between
4:00 and 6:00 PM. Normal 8:00 AM values are 5 to 23 fg/dL or 138 to 635
mmol/L. Normal 4:00 PM values are 3 to 16 fg/dL or 83 to 441 mmol/L.
 Explain the cortisol (dexamethasone) suppression—when healthy people
receive a low dose of dexamethasone (chemically similar to cortisol), ACTH
production is suppressed. However, people with adrenal hyperfunction and
some with endogenous depression continue to produce ACTH and do not
have a diurnal variation of cortisol.
o For this test, dexamethasone is given at bedtime. Blood samples are
taken the next day at 8:00
AM
and 4:00 PM. Medications are discontinued
for 24 to 48 hours before this test is started, especially estrogens,
phenytoin, and cortisol-related preparations. Radioisotopes should not be
given within 1 week of this test. This test is the test of choice to diagnose
Cushing’s syndrome.
 Cortisol stimulation test measures the response of the adrenal glands to an
injection of cosyntropin (Cortrosyn, a synthetic ACTH preparation).
o Blood is drawn for a fasting 8:00 AM cortisol level before cosyntropin is
administered.
o Then blood samples are taken 30 and 60 minutes after it is administered.
The adrenal glands normally respond to the cosyntropin by synthesizing
and secreting adrenocorticoids.
o The plasma cortisol level should increase to at least 18 fg/dL. The
response to cosyntropin is decreased or absent in people with adrenal
insufficiency or hypopituitarism.
 Urine vanillylmandelic acid, a metabolite of catecholamines, is rarely used
diagnostically today.
 Urine 17-ketosteroids and 17-hydroxycorticosteroids—these 24-hour urine
collection tests reflect adrenal function by measuring the urinary excretion of
steroids. They are used infrequently because they have been replaced by
serum immunoassays.
 Discuss that the adrenal scan is used to identify the site of certain tumors or
sites that produce excessive amounts of catecholamines. The radionuclide
iobenguane (131I) is injected intravenously, and scans are performed on days
2, 3, and 4. Sometimes only 1 day is needed, and other times imaging is
needed on days 6 and 7. Normally tumors and sites of hypersecretion are
absent. If ACTH levels are elevated, MRI of the pituitary should be done to
seek the source.