Level of consciousness, decreased
Level of consciousness, decreased: Excerpt from Signs & Symptoms: A 2-in-1 Reference for Nurses
A decrease in level of consciousness (LOC), which can range from lethargy to stupor to coma, usually results from a neurologic disorder and may signal a life-threatening complication, such as hemorrhage, trauma, or cerebral edema. However, this sign can also result from metabolic, GI, musculoskeletal, urologic, or cardiopulmonary disorders; severe nutritional deficiency; effects of toxins; or drug use. LOC can deteriorate suddenly or gradually and can remain altered temporarily or permanently.
Consciousness is affected by the reticular activating system (RAS), an intricate network of neurons with axons extending from the brain stem, thalamus, and hypothalamus to the cerebral cortex. A disturbance in any part of this integrated system prevents the intercommunication that makes consciousness possible. Loss of consciousness can result from a bilateral cerebral disturbance, an RAS disturbance, or both. Cerebral dysfunction characteristically produces the least dramatic decrease in a patient’s LOC. In contrast, dysfunction of the RAS produces the most dramatic decrease in LOC — coma.
The most sensitive indicator of decreased LOC is a change in the patient’s mental status. The Glasgow Coma Scale, which measures a patient’s ability to respond to verbal, sensory, and motor stimulation, can be used to quickly evaluate a patient’s LOC.
Emergency Actions
After evaluating the patient’s airway, breathing, and circulation, use the Glasgow Coma Scale to quickly determine his LOC and to obtain baseline data. (See Glasgow Coma Scale.) Insert an artificial airway, elevate the head of the bed 30 degrees and, if spinal cord injury has been ruled out, turn the patient’s head to the side. Prepare to suction the patient, if necessary. You may need to hyperventilate him to reduce carbon dioxide levels and decrease intracranial pressure (ICP). Then determine the rate, rhythm, and depth of spontaneous respirations. Support his breathing with a handheld resuscitation bag if necessary. If the patient’s Glasgow Coma Scale score is 7 or lower, intubation and resuscitation may be necessary. Continue to monitor the patient’s vital signs, being alert for signs of increasing ICP, such as bradycardia and widening pulse pressure. When his airway, breathing, and circulation are stabilized, perform a neurologic examination.
History
Try to obtain history information from the patient, if he’s lucid, and from his family. Did the patient complain of headache, dizziness, nausea, visual or hearing disturbances, weakness, fatigue, or any other problems before his LOC decreased? Has his family noticed any changes in the patient’s behavior, personality, memory, or temperament? Also ask about a history of neurologic disease or cancer; recent trauma or infection; drug and alcohol use; and the development of other signs and symptoms.
Physical assessment
Decreased LOC can result from a disorder affecting virtually any body system. After performing a complete neurologic examination, let the results of your history guide the rest of your physical assessment.
Medical causes
Adrenal crisis
Decreased LOC, ranging from lethargy to coma, may develop within 12 hours of adrenal crisis onset. Early associated findings include progressive weakness, irritability, anorexia, headache, nausea and vomiting, diarrhea, abdominal pain, and fever. Later signs and symptoms include hypotension; rapid, thready pulse; oliguria; cool, clammy skin; and flaccid extremities. The patient with chronic adrenocortical hypofunction may have hyperpigmented skin and mucous membranes.
Brain abscess
Decreased LOC varies from drowsiness to deep stupor, depending on abscess size and site. Early signs and symptoms — constant intractable headache, nausea, vomiting, and seizures — reflect increasing ICP. Typical later features include ocular disturbances (nystagmus, vision loss, and pupillary inequality) and signs of infection such as fever. Other findings may include personality changes, confusion, abnormal behavior, dizziness, facial weakness, aphasia, ataxia, tremor, and hemiparesis.
Brain tumor
In patients with brain tumors, LOC decreases slowly, from lethargy to coma. The patient may also experience apathy, behavior changes, memory loss, decreased attention span, morning headache, dizziness, vision loss, ataxia, and sensorimotor disturbances. Aphasia and seizures are possible, along with signs of hormonal imbalance, such as fluid retention or amenorrhea. Signs and symptoms vary according to the location and size of the tumor. In later stages, papilledema, vomiting, bradycardia, and widening pulse pressure also appear. In the final stages, the patient may exhibit decorticate or decerebrate posture.
Cerebral aneurysm (ruptured)
Somnolence, confusion and, at times, stupor characterize a moderate bleed; deep coma occurs with severe bleeding, which can be fatal. Onset of a ruptured cerebral aneurysm is usually abrupt, with sudden, severe headache, nausea, and vomiting. Nuchal rigidity, back and leg pain, fever, restlessness, irritability, occasional seizures, and blurred vision point to meningeal irritation. The type and severity of other findings vary with the site and severity of the hemorrhage and may include hemiparesis, hemisensory defects, dysphagia, and visual defects.
Cerebral contusion
Usually unconscious for a prolonged period, the patient may develop dilated, nonreactive pupils and decorticate or decerebrate posture. If he’s conscious or recovers consciousness, he may be drowsy, confused, disoriented, agitated, or even violent. Associated findings include blurred or double vision, fever, headache, pallor, diaphoresis, tachycardia, altered respirations, aphasia, and hemiparesis. Residual effects include seizures, impaired mental status, slight hemiparesis, and vertigo.
Diabetic ketoacidosis
Diabetic ketoacidosis produces a rapid decrease in LOC that ranges from lethargy to coma. It’s commonly preceded by polydipsia, polyphagia, and polyuria. The patient may complain of weakness, anorexia, abdominal pain, nausea, and vomiting. He may also exhibit orthostatic hypotension; fruity breath odor; Kussmaul’s respirations; warm, dry skin; and a rapid, thready pulse. Untreated, this condition invariably leads to coma and death.
Encephalitis
Within 48 hours of onset, the patient with encephalitis may develop LOC changes ranging from lethargy to coma. Other possible findings include abrupt onset of fever, headache, nuchal rigidity, nausea, vomiting, irritability, personality changes, seizures, aphasia, ataxia, hemiparesis, nystagmus, photophobia, myoclonus, and cranial nerve palsies.
Encephalopathy
With hepatic encephalopathy, signs and symptoms develop in four stages: in the prodromal stage, slight personality changes (disorientation, forgetfulness, slurred speech) and slight tremor; in the impending stage, tremor progressing to asterixis (the hallmark of hepatic encephalopathy), lethargy, aberrant behavior, and apraxia; in the stuporous stage, stupor and hyperventilation, with the patient noisy and abusive when aroused; in the comatose stage, coma with decerebrate posture, hyperactive reflexes, positive Babinski’s reflex, and fetor hepaticus.
With life-threatening hypertensive encephalopathy, LOC progressively decreases from lethargy to stupor to coma. Besides markedly elevated blood pressure, the patient may experience severe headache, vomiting, seizures, visual disturbances, transient paralysis, and eventually Cheyne-Stokes respirations.
With hypoglycemic encephalopathy, LOC rapidly deteriorates from lethargy to coma. Early signs and symptoms include nervousness, restlessness, agitation, and confusion; hunger; alternate flushing and cold sweats; and headache, trembling, and palpitations. Blurred vision progresses to motor weakness, hemiplegia, dilated pupils, pallor, decreased pulse rate, shallow respirations, and seizures. Flaccidity and decerebrate posture appear late.
Depending on its severity, hypoxic encephalopathy produces a sudden or gradual decrease in LOC, leading to coma and brain death. Early on, the patient appears confused and restless, with cyanosis and increased heart and respiratory rates and blood pressure. Later, his respiratory pattern becomes abnormal, and assessment reveals decreased pulse, blood pressure, and deep tendon reflexes (DTRs); Babin-ski’s reflex; absent doll’s eye sign; and fixed pupils.
With uremic encephalopathy, LOC decreases gradually from lethargy to coma. Early on, the patient may appear apathetic, inattentive, confused, and irritable and may complain of headache, nausea, fatigue, and anorexia. Other findings include vomiting, tremors, edema, papilledema, hypertension, cardiac arrhythmias, dyspnea, crackles, oliguria, and Kussmaul’s and Cheyne-Stokes respirations.
Epidural hemorrhage (acute)
Acute epidural hemorrhage, a life-threatening posttraumatic disorder, produces momentary loss of consciousness, sometimes followed by a lucid interval. While lucid, the patient has a severe headache, nausea, vomiting, and bladder distention. Rapid deterioration in consciousness follows, possibly leading to coma. Other findings include irregular respirations, seizures, decreased and bounding pulse, increased pulse pressure, hypertension, unilateral or bilateral fixed and dilated pupils, unilateral hemiparesis or hemiplegia, decerebrate posture, and Babinski’s reflex.
Heatstroke
As body temperature increases, LOC gradually decreases from lethargy to coma. Early signs and symptoms of heatstroke include malaise, tachycardia, tachypnea, orthostatic hypotension, muscle cramps, rigidity, and syncope. The patient may be irritable, anxious, and dizzy and may report a severe headache. At the onset of heatstroke, the patient’s skin is hot, flushed, and diaphoretic with blotchy cyanosis; later, when his fever exceeds 105° F (40.6° C), his skin becomes hot, flushed, and anhidrotic. Pulse and respiratory rate increase markedly, and blood pressure drops precipitously. Other findings include vomiting, diarrhea, dilated pupils, and Cheyne-Stokes respirations.
Hypernatremia
Hypernatremia, life-threatening if acute, causes LOC to deteriorate from lethargy to coma. The patient is irritable and exhibits twitches progressing to seizures. Other associated signs and symptoms include a weak, thready pulse; nausea; malaise; fever; thirst; flushed skin; and dry mucous membranes.
Hyperosmolar hyperglycemic nonketotic syndrome
LOC decreases rapidly from lethargy to coma in hyperosmolar hyperglycemic nonketotic syndrome (HHNS). Early findings include polyuria, polydipsia, weight loss, and weakness. Later, the patient may develop hypotension, poor skin turgor, dry skin and mucous membranes, tachycardia, tachypnea, oliguria, and seizures.
Hypokalemia
With hypokalemia, LOC gradually decreases to lethargy; coma is rare. Other findings include confusion, nausea, vomiting, diarrhea, polyuria, weakness, decreased reflexes, malaise, dizziness, hypotension, arrhythmias, and abnormal electrocardiogram results.
Hyponatremia
Hyponatremia, life-threatening if acute, produces decreased LOC in late stages. Early nausea and malaise may progress to behavior changes, confusion, lethargy, incoordination and, eventually, seizures and coma.
Hypothermia
With severe hypothermia (temperature below 90° F [32.2° C]), LOC decreases from lethargy to coma. DTRs disappear, and ventricular fibrillation occurs, possibly followed by cardiopulmonary arrest. With mild to moderate hypothermia, the patient may experience memory loss and slurred speech as well as shivering, weakness, fatigue, and apathy. Other early signs and symptoms include ataxia, muscle stiffness, and hyperactive DTRs; diuresis; tachycardia and decreased respiratory rate and blood pressure; and cold, pale skin. Later, muscle rigidity and decreased reflexes may develop, along with peripheral cyanosis, bradycardia, arrhythmias, severe hypotension, decreased respiratory rate with shallow respirations, and oliguria.
Intracerebral hemorrhage
Intracerebral hemorrhage, a life-threatening disorder, produces a rapid, steady loss of consciousness within hours, commonly accompanied by severe headache, dizziness, nausea, and vomiting. Associated signs and symptoms vary and may include increased blood pressure, irregular respirations, Babinski’s reflex, seizures, aphasia, decreased sensations, hemiplegia, decorticate or decerebrate posture, and dilated pupils.
Meningitis
Confusion and irritability are expected; however, stupor, coma, and seizures may occur in those with severe meningitis. Fever develops early, possibly accompanied by chills. Associated findings include severe headache, nuchal rigidity, hyperreflexia and, possibly, opisthotonos. The patient exhibits Kernig’s and Brudzinski’s signs and, possibly, ocular palsies, photophobia, facial weakness, and hearing loss.
Myxedema crisis
The patient experiencing myxedema crisis may exhibit a swift decline in LOC. Other findings include severe hypothermia, hypoventilation, hypotension, bradycardia, hypoactive reflexes, periorbital and peripheral edema, impaired hearing and balance, and seizures.
Pontine hemorrhage
With pontine hemorrhage, a sudden, rapid decrease in LOC to the point of coma occurs within minutes; death occurs within hours. The patient may also exhibit total paralysis, decerebrate posture, Babinski’s reflex, absent doll’s eye sign, and bilateral miosis (however, the pupils remain reactive to light).
Seizure disorders
A complex partial seizure produces decreased LOC, manifested as a blank stare, purposeless behavior (picking at clothing, wandering, lip smacking or chewing motions), and unintelligible speech. The seizure may be heralded by an aura and followed by several minutes of mental confusion.
An absence seizure usually involves a brief change in LOC, indicated by blinking or eye rolling, blank stare, and slight mouth movements.
A generalized tonic-clonic seizure typically begins with a loud cry and sudden loss of consciousness. Muscle spasm alternates with relaxation. Tongue biting, incontinence, labored breathing, apnea, and cyanosis may also occur. Consciousness returns after the seizure, but the patient remains confused and may have difficulty talking. He may complain of drowsiness, fatigue, headache, muscle aching, and weakness and may fall into deep sleep.
An atonic seizure produces sudden unconsciousness for a few seconds.
Status epilepticus, rapidly recurring seizures without intervening periods of physiologic recovery and return of consciousness, can be life-threatening.
Shock
Decreased LOC — lethargy progressing to stupor and coma — occurs late in shock. Associated findings include confusion, anxiety, and restlessness; hypotension; tachycardia; weak pulse with narrowing pulse pressure; dyspnea; oliguria; and cool, clammy skin.
Hypovolemic shock is generally the result of massive or insidious bleeding, either internally or externally. Cardiogenic shock may produce chest pain or arrhythmias and signs of heart failure, such as dyspnea, cough, edema, jugular vein distention, and weight gain. Septic shock may be accompanied by high fever and chills. Anaphylactic shock usually involves stridor.
Stroke
With stroke, LOC changes vary in degree and onset, depending on the lesion’s size and location and the presence of edema. A thrombotic stroke usually follows multiple transient ischemic attacks (TIAs). LOC changes may be abrupt or take several minutes, hours, or days. An embolic stroke occurs suddenly, and deficits reach their peak almost at once. Deficits associated with a hemorrhagic stroke usually develop over minutes or hours.
Associated findings vary with stroke type and severity and may include disorientation; intellectual deficits, such as memory loss and poor judgment; personality changes; and emotional lability. Other possible findings include dysarthria, dysphagia, ataxia, aphasia, apraxia, agnosia, unilateral sensorimotor loss, and visual disturbances. In addition, urine retention, incontinence, constipation, headache, vomiting, and seizures may occur.
CULTURAL CUE:The incidence of stroke is higher in Blacks than Whites. In fact, Blacks have a 60% higher risk for stroke than Whites or Hispanics of the same age. This is believed to be the result of an increased prevalence of hypertension in Blacks.
Subdural hematoma (chronic)
LOC deteriorates slowly in patients with chronic subdural hematomas. Other signs and symptoms include confusion, decreased ability to concentrate, and personality changes accompanied by headache, light-headedness, seizures, and a dilated ipsilateral pupil with ptosis.
Subdural hemorrhage (acute)
With acute subdural hemorrhage, a potentially life-threatening disorder, agitation and confusion are followed by progressively decreasing LOC from somnolence to coma. The patient may also experience headache, fever, unilateral pupil dilation, decreased pulse and respiratory rates, widening pulse pressure, seizures, hemiparesis, and Babinski’s reflex.
Thyroid storm
LOC decreases suddenly and can progress to coma. Irritability, restlessness, confusion, and psychotic behavior precede the deterioration. Associated signs and symptoms of a thyroid storm include tremors and weakness; visual disturbances; tachycardia, arrhythmias, angina, and acute respiratory distress; warm, moist, flushed skin; and vomiting, diarrhea, and fever to 105°F (40.6°C).
TIA
LOC decreases abruptly (with varying severity) and gradually returns to normal within 24 hours of a TIA. Site-specific findings may include vision loss, nystagmus, aphasia, dizziness, dysarthria, unilateral hemiparesis or hemiplegia, tinnitus, paresthesia, dysphagia, or staggering or incoordinated gait.
West Nile encephalitis
Signs and symptoms of this brain infection caused by the West Nile virus include fever, headache, and body aches, commonly with skin rash and swollen lymph glands. More severe infection is marked by high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, occasional seizures, paralysis and, rarely, death.
Other causes
Alcohol
Alcohol use causes varying degrees of sedation, irritability, and incoordination; intoxication commonly causes stupor.
Drugs
Sedation and other degrees of decreased LOC can result from an overdose of a barbiturate, another central nervous system depressant, or aspirin.
Poisoning
Toxins, such as lead, carbon monoxide, and snake venom, can cause varying degrees of decreased LOC. Confusion is common, as are headache, nausea, and vomiting. Other general features include hypotension, cardiac arrhythmias, dyspnea, sensorimotor loss, and seizures.
Special considerations
Reassess the patient’s LOC and neurologic status at least hourly. Carefully monitor ICP and intake and output. Ensure airway patency and proper nutrition. Take precautions to help ensure the patient’s safety. Keep him on bed rest with the side rails up, and maintain seizure precautions. Keep emergency resuscitation equipment at the patient’s bedside. Prepare the patient for a computed tomography scan of the head, magnetic resonance imaging of the brain, EEG, and lumbar puncture. Keep the head of the bed elevated at least 30 degrees. Don’t administer an opioid or a sedative because either may further decrease the patient’s LOC and hinder an accurate, meaningful neurologic examination. Apply restraints only if necessary because their use may increase his agitation and confusion.
Pediatric pointers
The primary cause of decreased LOC in children is head trauma, which usually results from physical abuse or a motor vehicle accident. Other causes include accidental poisoning, hydrocephalus, and meningitis or brain abscess following an ear or a respiratory infection. To reduce the parents’anxiety, include them in the child’s care. Offer them support and realistic explanations of their child’s condition.
Patient counseling
Talk to the patient even if he appears comatose; your voice may help reorient him to reality. Explain all treatments and procedures to the patient and his family. Explain all safety and seizure precautions. Discuss quality-of-life decisions with the patient and his family, and make the appropriate referrals to other sources of support such as hospice care.
Pictures
Book Source Details
- Book Title: Signs & Symptoms: A 2-in-1 Reference for Nurses
- Author(s): Springhouse
- Year of Publication: 2007
- Copyright Details: Signs & Symptoms: A 2-in-1 Reference for Nurses, Copyright © 2007 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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