Download Chapter 18: Neurologic Emergencies

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• Neurologic problems can be dangerous because depressed reflexes leave the airway and
other body systems vulnerable.
• The central nervous system has two major structures: the brain and the spinal cord. They
communicate with a neural network to regulate breathing, pulse rate, blood pressure, and
complex cognitive functions such as memory and understanding.
• The peripheral nervous system consists of the somatic nervous system, which controls
voluntary muscles, and the autonomic nervous system, which oversees sympathetic (fightor-flight) and parasympathetic responses.
• Each portion of the brain is responsible for specific functions. The occipital lobe receives
and stores images. The temporal lobe makes language and speech possible. The frontal lobe
controls voluntary motion. The parietal lobe allows perception of the sensations of touch
and pain. The diencephalon filters out unneeded information from the cerebral cortex. The
midbrain helps to regulate the level of consciousness. The brainstem regulates the blood
pressure, pulse rate, and respiratory rate and pattern. The hypothalamus and pituitary
control the release of epinephrine and norepinephrine from the endocrine system. The
cerebellum allows unconscious management of complex motor activity.
• Nerve cells, or neurons, transmit signals along their axons and across synapses by means of
chemical neurotransmitters.
• A variety of disease processes can cause neurologic dysfunction, including cancer,
degenerative conditions, developmental anomalies, infectious diseases, and vascular
conditions. Most neurologic diseases are thought to be multifactorial—that is, a number of
factors combine to induce vulnerability to a particular disease process.
• Intracranial pressure is determined by the volume of the intracranial contents: the brain,
blood, and cerebrospinal fluid.
• The primary dangers of increased intracranial pressure are ischemia and brain herniation.
• The neurologic assessment identifies small alterations that can impair nervous system
function.
• Investigating the neurologic patient’s chief complaint requires taking a history to determine
the mechanism of injury or the nature of the illness. This task is more difficult when the
patient is unresponsive, but environmental clues and the reports of family, friends, and
bystanders can be helpful.
• It is critical to determine when the patient was last seen normal because the amount of time
elapsed since the onset of symptoms will dictate the treatments available.
• Level of conscious can be evaluated using the Glasgow Coma Scale, the AVPU mnemonic,
a test of corneal reflex or pupillary response, evaluation of cranial nerve functioning,
assessment of the patient’s orientation and alertness, assessment of the patient’s speech and
ability to recognize and name objects, evaluation of the patient’s movement, testing of the
patient’s sensory perceptual abilities, testing of the blood glucose level, and measurement of
the vital signs.
• Following a set of standard care guidelines can help you address common neurologic
problems in a systematic way.
• Stroke is a condition in which the blood supply to the brain is interrupted. In ischemic
stroke, the blood supply may be blocked by a clot (thrombus or embolus). In hemorrhagic
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stroke, a damaged artery bleeds into the brain instead of carrying the blood to the brain,
Stroke causes sudden-onset changes in neurologic status, including effects on language,
movement, sensation, level of consciousness, and blood pressure.
Time is brain. Fibrinolytic (clot-busting) agents need to be administered within 3 hours of
the onset of a stroke in order for the agents to be effective. To achieve this target, a stroke
must be recognized and EMS dispatched quickly, and the patient must be transported
rapidly to an appropriate facility, such as a stroke center.
Transient ischemic attacks are episodes of cerebral ischemia that resolve within 24 hours,
leaving no permanent damage. They may, however, signal an underlying vascular problem
that can lead to a stroke. Prompt medical evaluation is essential.
A diminished level of consciousness is marked by increasing deficits in cognition and
speech and changes in movement and posture. The patient may become comatose without
timely medical intervention.
Seizures are cause by the sudden, erratic firing of neurons. Lengthy seizures can have
devastating effects on the brain and body and can even be life threatening.
Seizures have a wide range of causes, from drug use to tumors.
Seizures are classified as either generalized, affecting large portions of the brain, or partial,
affecting only a limited area of the brain.
Generalized seizures are divided into tonic/clonic (grand mal) seizures, which follow a
particular sequence; absence (petit mal) seizures, which are characterized not by movement
but by the absence of it; and pseudoseizures, which have a psychiatric origin.
Simple partial seizures involve either movement of one part of the body (frontal lobe) or
sensations in one part of the body (parietal lobe). Complex partial seizures subtly diminish
the level of consciousness, causing confusion, a lack of alertness, or an inability to speak.
Status epilepticus can be defined as a seizure that lasts longer than 4 to 5 minutes or
consecutive seizures without consciousness returning between seizures.
Syncope, or fainting, is caused by a brief interruption in cerebral blood flow that can be
traced to cardiac rhythm disturbances, other cardiac causes, or noncardiac causes.
Headaches can be classified as muscle tension, migraine, cluster, or sinus headaches. Each
has a different cause and a different presentation. Other types of headache may occur as
well.
Dementia is not a single illness, but a chronic process that can take many forms. It is
characterized by deterioration of memory, personality, language skills, perception,
reasoning, or judgment, with no loss of consciousness. Management is similar for the
various dementias and is primarily supportive.
Tumors of the neurologic system affect the brain and spinal cord and are classified as either
primary or metastatic disease.
Demyelinating conditions attack the insulating sheath that surrounds and protects the axon,
so that nerve impulses can no longer travel smoothly.
Multiple sclerosis is an autoimmune condition in which episodic attacks are followed by
periods of remission. Patients with multiple sclerosis can have a range of neurologic
deficits, from incontinence to significant sensory impairments.
Amyotrophic lateral sclerosis (Lou Gehrig disease) is a disease that strikes the voluntary
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motor neurons, causing progressive paralysis and death.
Parkinson disease damages the substantia nigra, the portion of the brain that produces
dopamine, which is needed for muscle contraction.
Cranial nerve disorders have a range of signs and symptoms and are often mistaken for
other disorders.
Dystonias are severe, abnormal muscle spasms that cause bizarre contortions, repetitive
motions, or postures. They can affect the neck, face, jaw, or other muscles, and they are
often painful.
Encephalitis and meningitis are central nervous system infections that cause inflammation
of the brain and meninges, respectively.
Abscesses indicate the presence of an infectious agent within the brain or spinal cord.
Polio is a viral infection that can cause long-term damage to the brain and brainstem,
leading to muscle weakness and paralysis.
Peripheral neuropathy is a group of conditions in which the nerves leaving the spinal cord
are damaged by trauma, toxins, tumors, autoimmune attack, and metabolic disorders, or
other processes.
Normal-pressure hydrocephalus is a rare condition that occurs in older adults for unknown
reasons. Increased intracranial pressure hydrocephalus occurs primarily among infants with
congenital malformations. It causes increased pressure within the cranial vault.
Cerebral palsy is a developmental condition characterized by damage to the frontal lobe of
the brain. Its cause is unclear.