Babinski’s reflex—dorsiflexion of the great toe with extension and fanning of the other toes—is an abnormal reflex elicited by firmly stroking the lateral aspect of the sole of the foot with a blunt object. (See How to elicit Babinski’s reflex.) In some patients, this reflex can be triggered by noxious stimuli, such as pain, noise, or even bumping of the bed. An indicator of corticospinal damage, Babinski’s reflex may occur unilaterally or bilaterally and may be temporary or permanent. A temporary Babinski’s reflex commonly occurs during the postictal phase of a seizure, whereas a permanent Babinski’s reflex occurs with corticospinal damage. A positive Babinski’s reflex is normal in neonates and in infants up to age 24 months.

If life-threatening causes of back pain are ruled out, continue with a complete history and physical examination. Be aware of the patient’s expressions of pain as you do so. Obtain a medical history, including past injuries and illnesses, and a family history. Ask about diet and alcohol intake. Also, take a drug history, including past and present prescription and over-the-counter drugs.

Next, perform a thorough physical examination. Observe skin color, especially in the patient’s legs, and palpate skin temperature. Palpate femoral, popliteal, posterior tibial, and pedal pulses. Ask about unusual sensations in the legs, such as numbness and tingling. Observe the patient’s posture if pain doesn’t prohibit standing. Does he stand erect or tend to lean toward one side? Observe the level of the shoulders and pelvis and the curvature of the back. Ask the patient to bend forward, backward, and from side to side while you palpate for paravertebral muscle spasms. Note rotation of the spine on the trunk. Palpate the dorsolumbar spine for point tenderness. Then ask the patient to walk—first on his heels, then on his toes; protect him from falling as he does so. Weakness may reflect a muscular disorder or spinal nerve root irritation. Place the patient in a sitting position to evaluate and compare patellar tendon (knee), Achilles tendon, and Babinski’s reflexes. Evaluate the strength of the extensor hallucis longus by asking the patient to hold up his big toe against resistance. Measure leg length and hamstring and quadriceps muscles
bilaterally. Note a difference of more than 3/8″ (1 cm) in muscle size, especially in the calf.

To reproduce leg and back pain, place the patient in a supine position on the examining table. Grasp his heel and slowly lift his leg. If he feels pain, note its exact location and the angle between the table and his leg when it occurs. Repeat this maneuver with the opposite leg. Pain along the sciatic nerve may indicate disk herniation or sciatica. Also, note the range of motion of the hip and knee.

Palpate the flanks and percuss with the fingertips or perform fist percussion to elicit costovertebral angle tenderness.

♦ Abdominal aortic aneurysm (dissecting). Life-threatening dissection of an abdominal aortic aneurysm may initially cause low back pain or dull abdominal pain, but it usually produces constant upper abdominal pain. A pulsating abdominal mass may be palpated in the epigastrium; after rupture, though, it no longer pulsates. Aneurysm dissection can also cause mottled skin below the waist, absent femoral and pedal pulses, blood pressure that’s lower in the legs than in the arms, mild to moderate tenderness with guarding, and abdominal rigidity. Signs of shock (such as cool, clammy skin) appear if blood loss is significant.

♦ Ankylosing spondylitis. Ankylosing spondylitis is a chronic, progressive disorder that causes sacroiliac pain, which radiates up the spine and is aggravated by lateral pressure on the pelvis. The pain is usually most severe in the morning or after a period of inactivity and isn’t relieved by rest. Abnormal rigidity of the lumbar spine with forward flexion is also characteristic. This disorder can cause local tenderness, fatigue, fever, anorexia, weight loss, and occasionally iritis.

♦ Appendicitis. Appendicitis is a life-threatening disorder in which a vague and dull discomfort in the epigastric or umbilical region migrates to McBurney’s point in the right lower quadrant. In retrocecal appendicitis, pain may also radiate to the back. The shift in pain is preceded by anorexia and nausea and is accompanied by fever, occasional vomiting, abdominal tenderness (especially over McBurney’s point), and rebound tenderness. Some patients also have painful urinary urgency.

♦ Cholecystitis. Cholecystitis produces severe pain in the right upper quadrant of the abdomen that may radiate to the right shoulder, chest, or back. The pain may arise suddenly or may increase gradually over several hours; many patients have a history of similar pain after a highfat meal. Accompanying signs and symptoms include anorexia, fever, nausea, vomiting, rightupper-quadrant tenderness, abdominal rigidity, pallor, and sweating.

♦ Chordoma. A slowly developing malignant tumor, chordoma causes persistent pain in the lower back, sacrum, and coccyx. As the tumor expands, pain may be accompanied by constipation and bowel or bladder incontinence.

♦ Endometriosis. Endometriosis causes deep sacral pain and severe cramping pain in the lower abdomen. The pain worsens just before or during menstruation and may be aggravated by defecation. It’s accompanied by constipation, abdominal tenderness, dysmenorrhea, and dyspareunia.

♦ Intervertebral disk rupture. Intervertebral disk rupture produces gradual or sudden low back pain with or without leg pain (sciatica). It rarely produces leg pain alone. Pain usually begins in the back and radiates to the buttocks and leg. The pain is exacerbated by activity, coughing, and sneezing and is eased by rest. It’s accompanied by paresthesia (most commonly, numbness or tingling in the lower leg and foot), paravertebral muscle spasm, and decreased reflexes on the affected side. This disorder also affects posture and gait. The patient’s spine is slightly flexed and he leans toward the painful side. He walks slowly and rises from a sitting to a standing position with extreme difficulty.

♦ Lumbosacral sprain. Lumbosacral sprain causes localized aching pain and tenderness associated with muscle spasm on lateral motion. The recumbent patient typically flexes his knees and hips to help ease pain. Flexion of the spine and movement intensify the pain, whereas rest helps relieve it.

♦ Metastatic tumors. Metastatic tumors commonly spread to the spine, causing low back pain in at least 25% of patients. Typically, the pain begins abruptly, is accompanied by cramping muscle pain (usually worse at night), and isn’t relieved by rest.

♦ Myeloma. Back pain caused by myeloma—a primary malignant tumor—usually begins abruptly and worsens with exercise. It may be accompanied by arthritic signs and symptoms, such as achiness, joint swelling, and tenderness. Other signs and symptoms include fever, malaise, peripheral paresthesia, and weight loss.

♦ Pancreatitis (acute). Pancreatitis is a lifethreatening disorder that usually produces fulminating, continuous upper abdominal pain that may radiate to both flanks and to the back. To relieve this pain, the patient may bend forward, draw his knees to his chest, or move about restlessly.

Early associated signs and symptoms include abdominal tenderness, nausea, vomiting, fever, pallor, and tachycardia; some patients experience abdominal guarding and rigidity, rebound tenderness, and hypoactive bowel sounds. Jaundice may be a late sign. Occurring as inflammation subsides, Turner’s sign (ecchymosis of the abdomen or flank) or Cullen’s sign (bluish discoloration of skin around the umbilicus and in both flanks) signals hemorrhagic pancreatitis.

♦ Perforated ulcer. In some patients, perforation of a duodenal or gastric ulcer causes sudden, prostrating epigastric pain that may radiate throughout the abdomen and to the back. This life-threatening disorder also causes boardlike abdominal rigidity, tenderness with guarding, generalized rebound tenderness, absence of bowel sounds, and grunting, shallow respirations. Associated signs include fever, tachycardia, and hypotension.

♦ Prostate cancer. Chronic aching back pain may be the only symptom of prostate cancer. This disorder may also cause hematuria and decreased urine stream.

♦ Pyelonephritis (acute). Pyelonephritis produces progressive flank and lower abdominal pain accompanied by back pain or tenderness (especially over the costovertebral angle). Other signs and symptoms include high fever and chills, nausea and vomiting, flank and abdominal tenderness, and urinary frequency and urgency.

♦ Reiter’s syndrome. In some patients, sacroiliac pain is the first sign of Reiter’s syndrome. Pain is accompanied by the classic triad of conjunctivitis, urethritis, and arthritis.

♦ Renal calculi. The colicky pain of renal calculi usually results from irritation of the ureteral lining, which increases the frequency and force of peristaltic contractions. The pain travels from the costovertebral angle to the flank, suprapubic region, and external genitalia. It varies in intensity but may become excruciating if calculi travel down a ureter. Calculi in the renal pelvis and calyces may cause dull and constant flank pain. Renal calculi also cause nausea, vomiting, urinary urgency (if a calculus lodges near the bladder), hematuria, and agitation due to pain. Pain resolves or significantly decreases after calculi move to the bladder. Encourage the patient to recover any expelled calculi for analysis.

♦ Sacroiliac strain. Sacroiliac strain causes sacroiliac pain that may radiate to the buttock, hip, and lateral aspect of the thigh. The pain is aggravated by weight bearing on the affected extremity and by abduction with resistance of the leg. Associated signs and symptoms include tenderness of the symphysis pubis and a limp or a gluteus medius or abductor lurch.

♦ Smallpox (variola major). Worldwide eradication of smallpox was achieved in 1977; the United States and Russia have the only known storage sites of the virus. The virus is considered a potential agent for biological warfare. Initial signs and symptoms include high fever, malaise, prostration, severe headache, backache, and abdominal pain. A maculopapular rash develops on the oral mucosa, pharynx, face, and forearms and then spreads to the trunk and legs. Within 2 days, the rash becomes vesicular and later pustular. The lesions develop at the same time, appear identical, and are more prominent on the face and extremities. The pustules are round, firm, and deeply embedded in the skin. After 8 to 9 days, the pustules form a crust, which later separates from the skin, leaving a pitted scar. Death may result from encephalitis, extensive bleeding, or secondary infection.

♦ Spinal neoplasm (benign). Spinal neoplasm typically causes severe localized back pain and scoliosis.

♦ Spinal stenosis. Resembling a ruptured intervertebral disk, spinal stenosis produces back pain with or without sciatica, which commonly affects both legs. The pain may radiate to the toes and may progress to numbness or weakness unless the patient rests.

♦ Spondylolisthesis. A major structural disorder characterized by forward slippage of one vertebra onto another, spondylolisthesis may produce no symptoms or may cause low back pain with or without nerve root involvement. Associated symptoms of nerve root involvement include paresthesia, buttock pain, and pain radiating down the leg. Palpation of the lumbar spine may reveal a “step-off” of the spinous process. Flexion of the spine may be limited.

♦ Transverse process fracture. This type of fracture causes severe localized back pain with muscle spasm and hematoma.

♦ Vertebral compression fracture. A vertebral compression fracture may be painless

initially. Several weeks later, it causes back pain aggravated by weight bearing and local tenderness. Fracture of a thoracic vertebra may cause referred pain in the lumbar area.

♦ Vertebral osteomyelitis. Initially, vertebral osteomyelitis causes insidious back pain. As it progresses, the pain may become constant, more pronounced at night, and aggravated by spinal movement. Accompanying signs and symptoms include vertebral and hamstring spasms, tenderness of the spinous processes, fever, and malaise.

♦ Vertebral osteoporosis. Vertebral osteoporosis causes chronic aching back pain that is aggravated by activity and somewhat relieved by rest. Tenderness may also occur.

♦ Neurologic tests. Lumbar puncture and myelography can produce transient back pain.

Monitor the patient closely if the back pain suggests a life-threatening cause. Be alert for increasing pain, altered neurovascular status in the legs, loss of bowel or bladder control, altered vital signs, sweating, and cyanosis.

Until a tentative diagnosis is made, withhold analgesics, which may mask symptoms. Also withhold food and fluids in case surgery is necessary. Make the patient as comfortable as possible by elevating the head of the bed and placing a pillow under his knees. Encourage relaxation techniques such as deep breathing. Prepare the patient for a rectal or pelvic examination. He may also require routine blood tests, urinalysis, computed tomography scan, appropriate biopsies, and X-rays of the chest, abdomen, and spine.

Fit the patient for a corset or lumbosacral support, but instruct him not to wear it in bed. He may also require heat or cold therapy, a backboard, a convoluted foam mattress, or pelvic traction. Explain these pain-relief measures to the patient. Teach the patient about alternatives to analgesic drug therapy, such as biofeedback and transcutaneous electrical nerve stimulation.

Be aware that back pain is notoriously associated with malingering. Refer the patient to other professionals, such as a physical therapist, an occupational therapist, or a psychologist, if indicated.

Children may have difficulty describing back pain, so be alert for nonverbal clues, such as wincing or refusing to walk. Closely observe the family dynamics during history taking for clues of child abuse.

Back pain in children may stem from intervertebral disk inflammation (diskitis), neoplasms, idiopathic juvenile osteoporosis, and spondylolisthesis. Disk herniation typically doesn’t cause back pain. Scoliosis, a common disorder in adolescents, rarely causes back pain.

Suspect metastatic cancer—especially of the prostate, colon, or breast—in older patients with a recent onset of back pain that usually isn’t relieved by rest and worsens at night.

If the patient has chronic back pain, reinforce instructions about bed rest, analgesics, antiinflammatories, and exercise. (See Exercises for chronic low back pain.) Also, suggest that he take daily warm baths to help relieve pain. Help the patient recognize the need to make necessary lifestyle changes, such as losing weight or correcting poor posture. Advise patients with acute back pain secondary to a musculoskeletal problem to continue their daily activities as tolerated, rather than staying on total bed rest.

Begin by asking about a history of pulmonary disease. Note chronic exposure to environmental
irritants such as asbestos. Also ask about the patient’s smoking habits.

Then explore other signs and symptoms of pulmonary disease. Does the patient have a cough? Is it productive or nonproductive? If it’s productive, have him describe the sputum’s color and consistency. Does the patient experience shortness of breath? Is it related to activity? Although dyspnea is common with COPD, many patients fail to associate it with the disease. Instead, they blame “old age” or “getting out of shape” for causing dyspnea.

Auscultate for abnormal breath sounds, such as crackles and wheezing. Then percuss the chest. Hyperresonant sounds indicate trapped air; dull or flat sounds indicate mucus buildup. Be alert for accessory muscle use, intercostal retractions, and tachypnea, which may signal respiratory distress.

Finally, observe the patient’s general appearance. Look for central cyanosis in the cheeks, nose, and mucosa inside the lips. In addition, look for peripheral cyanosis in the nail beds. Also note clubbing, a late sign of COPD.

♦ Asthma. Typically, barrel chest develops only in chronic asthma. An acute asthma attack causes severe dyspnea, wheezing, and a productive cough. It can also cause prolonged
expiratory time, accessory muscle use, tachycardia, tachypnea, perspiration, and flushing.

♦ Chronic bronchitis. A late sign in chronic bronchitis, barrel chest is characteristically preceded by a productive cough and exertional dyspnea. This form of COPD may also cause cyanosis, tachypnea, wheezing, prolonged expiratory time, and accessory muscle use.

♦ Emphysema. Barrel chest is a late sign in this form of COPD. Typically, emphysema begins insidiously, with dyspnea the predominant symptom. Eventually, it may also cause chronic cough, anorexia, weight loss, malaise, accessory muscle use, pursed-lip breathing, tachypnea, peripheral cyanosis, and clubbing.

To ease breathing, have the patient sit and lean forward, resting his hands on his knees to support the upper torso (tripod position). This position allows maximum diaphragmatic excursion, facilitating chest expansion.

In infants, the ratio of anteroposterior to transverse diameter is normally 1:1. As the child grows, this ratio gradually changes to 1:2 by age 5 to 6. Cystic fibrosis and chronic asthma may cause barrel chest in children.

In elderly patients, senile kyphosis of the thoracic spine may be mistaken for barrel chest. However, patients with senile kyphosis lack signs of pulmonary disease.

Advise the patient to avoid bronchial irritants, especially smoking, which may exacerbate COPD. Tell him to report purulent sputum production, which may indicate upper respiratory tract infection. Instruct him to space his activities to help minimize exertional dyspnea.

Perform a complete neurologic examination, beginning with the history. Ask the patient about recent trauma to the head. Did he sustain a severe blow to the head? Was he involved in a motor vehicle accident? Note the patient’s level of consciousness as he responds. Does he respond quickly or slowly? Are his answers appropriate, or does he appear confused?

Check the patient’s vital signs; be alert for widening pulse pressure and bradycardia, signs of increased intracranial pressure. Assess cranial nerve function in nerves II, III, IV, VI, VII, and VIII. Evaluate pupillary size and response to light as well as motor and verbal responses. Relate these data to the Glasgow Coma Scale. Also, note cerebrospinal fluid (CSF) leakage from the nose or ears. Ask about postnasal drip, which may reflect CSF drainage down the throat. Look for the halo sign—a bloodstain encircled by a yellowish ring—on bed linens or dressings. To confirm that drainage is CSF, test it with a Dextrostix; CSF is positive for glucose, whereas mucus isn’t. Follow up the neurologic examination with a complete physical examination to detect other injuries associated with a basilar skull fracture.

♦ Basilar skull fracture. Battle’s sign may be the only outward sign of a basilar skull fracture, or it may be accompanied by periorbital ecchymosis (raccoon eyes), conjunctival hemorrhage, nystagmus, ocular deviation, epistaxis, anosmia, a bulging tympanic membrane (from CSF or blood accumulation), visible fracture lines on the external auditory canal, tinnitus, difficulty hearing, facial paralysis, or vertigo.

Expect a patient with a basilar skull fracture to be on bed rest for several days to weeks. Keep him flat to decrease pressure on dural tears and to minimize CSF leakage. Monitor his neurologic status closely. Avoid nasogastric intubation and nasopharyngeal suction, which may cause cerebral infection. Also, caution the patient against blowing his nose, which may worsen a dural tear.

The patient may need skull X-rays and a computed tomography scan to help confirm a basilar skull fracture and to evaluate the severity of the head injury. Typically, these fractures and any associated dural tears heal spontaneously within several days to weeks. However, if the patient has a large dural tear, a craniotomy may be necessary to repair the tear with a graft patch.

Children who are victims of abuse commonly sustain basilar skull fractures from severe blows to the head. As in adults, Battle’s sign may be the only outward sign of fracture and, perhaps, the only clue to child abuse. If you suspect child abuse, follow hospital protocol for reporting the incident.

A late and ominous sign of neurologic deterioration, Biot’s respirations are characterized by irregular and unpredictable rate, rhythm, and depth. This rare breathing pattern may appear abruptly and may reflect increased pressure on the medulla coinciding with brain stem compression.

Observe the patient’s breathing pattern for several minutes to avoid confusing Biot’s respirations with other respiratory patterns. (See Identifying Biot’s respirations.) Prepare to intubate the patient and provide mechanical ventilation. Next, take vital signs, noting especially increased systolic pressure.

If distention isn’t severe, begin by reviewing the patient’s voiding patterns. Find out the time and amount of the patient’s last voiding and the amount of fluid consumed since then. Ask if he has difficulty urinating. Does he use Valsalva’s or Credé’s maneuver to initiate urination? Does he urinate with urgency or without warning? Is urination painful or irritating? Ask about the force and continuity of his urine stream and whether he feels that his bladder is empty after voiding.

Explore the patient’s history of urinary tract obstruction or infections; venereal disease; neurologic, intestinal, or pelvic surgery; lower abdominal or urinary tract trauma; and systemic or neurologic disorders. Ask about his drug history, including his use of over-the-counter drugs.

Take the patient’s vital signs, and percuss and palpate the bladder. (Remember that if the bladder is empty, it can’t be palpated through the abdominal wall.) Inspect the urethral meatus, and measure its diameter. Describe the appearance and amount of any discharge. Finally, test for perineal sensation and anal sphincter tone; in male patients, digitally examine the prostate gland.

♦ Benign prostatic hyperplasia (BPH). In BPH, bladder distention develops gradually as the prostate enlarges. Occasionally, its onset is acute. Initially, the patient experiences urinary hesitancy, straining, and frequency; reduced force of and inability to stop the urine stream; nocturia; and postvoiding dribbling. As the disorder progresses, it produces prostate enlargement, sensations of suprapubic fullness and incomplete bladder emptying, perineal pain, constipation, and hematuria.

♦ Bladder calculi. Bladder calculi may produce bladder distention, but pain is usually the only symptom. The pain is usually referred to the tip of the penis, the vulvar area, the lower back, or the heel. It worsens during walking or exercise and abates when the patient lies down. It’s usually most severe when micturition ceases. The pain may be accompanied by urinary frequency and urgency, terminal hematuria, and dysuria.

♦ Bladder cancer. By blocking the urethral orifice, neoplasms can cause bladder distention. Associated signs and symptoms include hematuria (most common sign); urinary frequency and urgency; nocturia; dysuria; pyuria; pain in the bladder, rectum, pelvis, flank, back, or legs; vomiting; diarrhea; and sleeplessness. A mass may be palpable on bimanual examination.

Bladder cancer is twice as common in Whites as in Blacks. It’s relatively uncommon among Asians, Hispanics, and Native Americans.

♦ Multiple sclerosis. In this neuromuscular disorder, urine retention and bladder distention result from interruption of upper motor neuron control of the bladder. Associated signs and symptoms include optic neuritis, paresthesia, impaired position and vibratory senses, diplopia, nystagmus, dizziness, abnormal reflexes, dysarthria, muscle weakness, emotional lability, Lhermitte’s sign (transient, electric-like shocks that spread down the body when the head is flexed), Babinski’s sign, and ataxia.

♦ Prostate cancer. Prostate cancer eventually causes bladder distention in about 25% of
patients. Usual signs and symptoms include dysuria, urinary frequency and urgency, nocturia, weight loss, fatigue, perineal pain, constipation, and induration of the prostate or a rigid, irregular prostate on digital rectal examination. In some patients, urine retention and bladder distention are the only signs.

Prostate cancer is more common in Blacks than in other ethnic groups.

♦ Prostatitis. In acute prostatitis, bladder distention occurs rapidly along with perineal discomfort and a sensation of suprapubic fullness. Other signs and symptoms include perineal pain; tense, boggy, tender, and warm enlarged prostate; decreased libido; impotence; decreased force of the urine stream; dysuria; hematuria; and urinary frequency and urgency. Additional signs and symptoms include fatigue, malaise, myalgia, fever, chills, nausea, and vomiting.

Bladder distention is rare in chronic prostatitis, which may be accompanied by perineal discomfort, a sensation of suprapubic fullness, prostatic tenderness, decreased libido, urinary frequency and urgency, dysuria, pyuria, hematuria, persistent urethral discharge, ejaculatory pain, and dull pain radiating to the lower back, buttocks, penis, or perineum.

♦ Spinal neoplasms. Disrupting upper neuron control of the bladder, spinal neoplasms cause neurogenic bladder and resultant distention. Associated signs and symptoms include a sense of pelvic fullness, continuous overflow dribbling, back pain that often mimics sciatica pain, constipation, tender vertebral processes, sensory deficits, and muscle weakness, flaccidity, and atrophy. Signs and symptoms of urinary tract infection (dysuria, urinary frequency and
urgency, nocturia, tenesmus, hematuria, and weakness) may also occur.

♦ Urethral calculi. In urethral calculi, urethral obstruction leads to interrupted urine flow and bladder distention. The obstruction causes pain radiating to the penis or vulva and referred to the perineum or rectum. It may also produce a palpable stone and urethral discharge.

♦ Urethral stricture. Urethral stricture results in urine retention and bladder distention with chronic urethral discharge (most common sign), urinary frequency (also common), dysuria, urgency, decreased force and diameter of the urine stream, and pyuria. Urinoma and urosepsis may also develop.

♦ Catheterization. Using an indwelling urinary catheter can result in urine retention and bladder distention. While the catheter is in place, inadequate drainage due to kinked tubing or an occluded lumen may lead to urine retention. In addition, a misplaced urinary catheter or irritation due to catheter removal may cause edema, thereby blocking urine outflow.

♦ Drugs. Parasympatholytics, anticholinergics, ganglionic blockers, sedatives, anesthetics, and opiates can produce urine retention and bladder distention.

Monitor the patient’s vital signs and the extent of bladder distention. Encourage the patient to change positions to alleviate discomfort. Provide an analgesic if necessary.

Prepare the patient for diagnostic tests (such as endoscopy and radiologic studies) to determine the cause of bladder distention. You may need to prepare him for surgery if interventions
fail to relieve bladder distention and obstruction prevents catheterization.

Look for urine retention and bladder distention in any infant who fails to void normal amounts. (In the first 48 hours of life, an infant excretes about 60 ml of urine; during the next week, he excretes about 300 ml of urine daily.) In males, posterior urethral valves, meatal stenosis, phimosis, spinal cord anomalies, bladder diverticula, and other congenital defects may cause urinary obstruction and resultant bladder distention.

If the patient doesn’t require immediate urinary catheterization, provide privacy and suggest that he assume the normal voiding position. Teach him to perform Valsalva’s maneuver, or gently perform Credé’s maneuver. You can also stroke or intermittently apply ice to the inner thigh, or help him relax in a warm tub or sitz bath. Use the power of suggestion to stimulate voiding. For example, run water in the sink, pour warm water over his perineum, place his hands in warm water, or play tapes of aquatic sounds.

Low blood pressure refers to inadequate intravascular pressure to maintain the body’s oxygen requirements. Although commonly linked to shock, this sign may also result from cardiovascular, respiratory, neurologic, or metabolic disorders. Hypoperfusion states especially affect the kidneys, brain, and heart, and may lead to renal failure, change in level of consciousness (LOC), or myocardial ischemia. Low blood pressure may also be caused by certain diagnostic tests—most commonly those using contrast media—and the use of certain drugs. It may stem from stress or a change of position—specifically, rising abruptly from a supine or sitting position to a standing position (orthostatic hypotension).

Normal blood pressure varies considerably; what qualifies as low blood pressure for one person may be perfectly normal for another. Consequently, every blood pressure reading must be compared against the patient’s baseline. Typically, a reading below 90/60 mm Hg, or a drop of 30 mm Hg from the baseline, is considered low blood pressure.

Low blood pressure can reflect an expanded intravascular space (as in severe infections, allergic reactions, or adrenal insufficiency), reduced intravascular volume (as in dehydration and hemorrhage), or decreased cardiac output (as in impaired cardiac muscle contractility). Because the body’s pressure-regulating mechanisms are complex and interrelated, a combination of these factors usually contributes to low blood pressure.

If the patient’s systolic pressure is less than 80 mm Hg, or 30 mm Hg below his baseline, suspect shock immediately. Quickly evaluate the patient for a decreased LOC. Check his apical pulse for tachycardia and respirations for tachypnea. Also, inspect the patient for cool, clammy skin. Elevate his legs above the level of his heart, or place him in Trendelenburg’s position if the bed can be adjusted. Then start an I.V. line using a large-bore catheter to replace fluids and blood or to administer drugs. Prepare to administer oxygen with mechanical ventilation if necessary. Monitor the patient’s intake and output, and insert an indwelling urinary catheter for the accurate measurement of urine. The patient may also need a central venous access device or a pulmonary artery catheter to facilitate monitoring of fluid status. Prepare for cardiac monitoring to evaluate cardiac rhythm. Be ready to insert a nasogastric tube to prevent aspiration in the comatose patient. Throughout emergency interventions, keep the patient’s spinal column immobile until spinal cord trauma is ruled out.