CNRN key terms

The brain's ability to maintain relatively constant blood flow despite changes in systemic blood pressure, primarily by adjusting the diameter of cerebral arterioles. It keeps perfusion stable within a mean arterial pressure range of roughly 60-160 mmHg.

The principle that the skull is a rigid container holding brain tissue, blood, and cerebrospinal fluid in a fixed total volume. An increase in one component must be offset by a decrease in another, or intracranial pressure rises.

A selective network of tight junctions between capillary endothelial cells in the brain that restricts passage of many substances from blood into brain tissue. It protects the brain but also limits entry of some medications.

Clear fluid produced mainly by the choroid plexus within the ventricles that cushions the brain and spinal cord, removes waste, and helps maintain stable intracranial pressure. It circulates through ventricles and is reabsorbed into venous sinuses.

A network of neurons in the brainstem that regulates wakefulness and arousal. Injury or compression can cause decreased level of consciousness even when cortical function is otherwise intact.

A standardized 3-15 point scale scoring eye opening, verbal response, and motor response to quantify level of consciousness. Lower scores indicate more severe impairment; it is used for triage and trending.

The degree of alertness and awareness, ranging from fully awake and oriented to unresponsive. It is the most important early indicator of neurological deterioration and is assessed before other neurological findings.

A 0-42 point standardized exam that quantifies stroke severity by assessing consciousness, gaze, visual fields, facial palsy, motor function, sensation, language, and neglect. Higher scores indicate more severe deficits.

The normal constriction of a pupil when light is shone into the eye, mediated by the optic and oculomotor nerves. Sluggish or unequal pupils can signal increased intracranial pressure or brain herniation.

The classic sign of increased intracranial pressure consisting of hypertension with widened pulse pressure, bradycardia, and irregular respirations. It is a late and life-threatening finding requiring immediate intervention.

Abnormal motor responses to pain indicating severe brain injury. Decorticate posturing involves flexion of arms toward the chest; decerebrate posturing involves extension and internal rotation of arms, indicating a lower (brainstem) lesion.

The pressure exerted inside the skull by brain tissue, blood, and cerebrospinal fluid. Normal adult ICP is generally 5-15 mmHg; sustained elevation can reduce cerebral perfusion and cause herniation.

The pressure gradient driving blood flow to the brain, calculated as mean arterial pressure minus intracranial pressure. It is typically targeted at 60-70 mmHg or higher to maintain adequate brain oxygenation.

Damage to the brain caused by an external mechanical force, such as a blow, fall, or penetrating injury. It can produce focal injury, diffuse axonal injury, hemorrhage, and swelling.

Downward or sideward displacement of brain tissue through openings in the skull due to increased pressure. It compresses vital brainstem structures and can rapidly cause coma, abnormal posturing, and death.

A collection of blood between the skull and the dura mater, often from a torn middle meningeal artery after head trauma. It may show a lucid interval followed by rapid deterioration.

Bleeding into the space between the arachnoid and pia mater, commonly from a ruptured cerebral aneurysm. It causes sudden severe headache, neck stiffness, and risk of vasospasm and rebleeding.

The area of brain tissue around an ischemic core that is at risk of infarction but still potentially salvageable because blood flow is reduced, not absent. Rapid reperfusion can rescue this tissue.

A thrombolytic medication used for acute ischemic stroke within a limited time window to dissolve the clot and restore blood flow. It requires strict screening for bleeding risk and close monitoring for hemorrhage.

A continuous seizure lasting five minutes or more, or repeated seizures without regaining consciousness between them. It is a medical emergency requiring rapid antiepileptic treatment to prevent brain injury.

A recording of electrical activity generated by the brain, obtained through electrodes placed on the scalp. It is used to detect seizures, evaluate altered consciousness, and monitor brain function.

An antiepileptic medication commonly used to prevent or treat seizures in hospitalized neuroscience patients. It is often chosen because it has few drug interactions and can be given intravenously.

A catheter placed into a ventricle to drain cerebrospinal fluid and measure intracranial pressure. It can be used to treat hydrocephalus and to monitor pressure after brain injury or hemorrhage.

A procedure in which a needle is inserted into the lumbar subarachnoid space to collect cerebrospinal fluid or measure opening pressure. It is used to diagnose infection, hemorrhage, and other neurological conditions.

A life-threatening syndrome in people with spinal cord injury above roughly T6, triggered by a noxious stimulus below the injury. It causes severe hypertension, pounding headache, sweating, and bradycardia and requires immediate removal of the trigger.

A form of distributive shock after spinal cord injury that causes hypotension and bradycardia due to loss of sympathetic vascular tone. It differs from hypovolemic shock and may require vasopressors.

A chronic autoimmune disease in which inflammation and demyelination damage the central nervous system. It causes relapsing or progressive neurological deficits and is managed with disease-modifying therapies and rehabilitation.

A progressive neurodegenerative disorder caused by loss of dopamine-producing neurons, leading to tremor, rigidity, bradykinesia, and postural instability. Medication and rehabilitation help manage symptoms; deep brain stimulation is an option.

An autoimmune neuromuscular disorder in which antibodies impair acetylcholine receptors at the neuromuscular junction, causing fluctuating muscle weakness that worsens with activity. It can affect breathing and swallowing.

An acute immune-mediated polyneuropathy causing ascending weakness, often starting in the legs, and loss of deep tendon reflexes. Respiratory monitoring is critical because weakness can progress to breathing failure.

The brain's ability to reorganize itself by forming new neural connections and pathways in response to learning, injury, or rehabilitation. It is the basis for recovery after stroke and other neurological damage.

Velocity-dependent increase in muscle tone caused by upper motor neuron damage, often after stroke, spinal cord injury, or multiple sclerosis. It can impair movement and comfort and may be treated with baclofen or botulinum toxin.

Difficulty swallowing that can occur after stroke, traumatic brain injury, or neuromuscular disease. It raises the risk of aspiration, dehydration, and malnutrition and requires screening and modified diets or therapy.

A surgical treatment that implants electrodes in specific brain targets and delivers electrical impulses to modulate abnormal neural activity. It is used for Parkinson's disease, essential tremor, and some other movement disorders.

An osmotic diuretic given intravenously to reduce intracranial pressure by drawing water out of brain tissue into the blood. It requires monitoring of kidney function, electrolytes, and serum osmolality.

The irreversible cessation of all brain function, including the brainstem, while the heart may still beat with support. Diagnosis follows strict clinical criteria and may include apnea testing and confirmatory studies.

Drugs that carry a heightened risk of serious harm when used incorrectly, such as anticoagulants, insulin, and opioids. Neuroscience nurses use independent double checks and standardized protocols to prevent errors.

Treatment given to counteract the blood-thinning effect of anticoagulant drugs and stop or prevent serious bleeding. Agents include vitamin K, protamine, and specific reversal products depending on the anticoagulant.

The likelihood that a patient will fall because of factors such as weakness, imbalance, confusion, medications, or sensory deficits. Neuroscience patients often have multiple risks requiring bed alarms and assisted mobility.