NSG210 Hinkle Ch. 60: Assessment of Neurologic Function
Source: Hinkle & Cheever, Brunner & Suddarth’s Medical-Surgical Nursing 15e, Chapter 60, pp. 1966-1991 (textbooks/HINKLE_MS_CH60.pdf, also in textbooks/exam04/). Week 11 reading (alterations in cognition and sensing, November 4); Exam 4 content (the course calendars end Exam 3 content with the October 28 OB lecture). Numbering note: the syllabus lists “Ch. 61” (16th edition); neurologic assessment is Ch. 60 in the 15th edition (see nsg210-textbook-chapter-crosswalk). Glasgow Coma Scale, ICP and altered consciousness are in nsg210-hinkle-ch61-neurologic-dysfunction.
Learning Outcomes
- Describe the structures and functions of the central and peripheral nervous systems.
- Differentiate pathologic changes affecting motor control from those affecting sensory pathways.
- Compare the sympathetic and parasympathetic nervous systems.
- Explain the significance of physical assessment in diagnosing neurologic dysfunction.
- Discuss diagnostic tests for suspected neurologic disorders and their nursing implications.
Key Terms
- Agnosia: loss of ability to recognize objects through a particular sense (visual, auditory, tactile)
- Ataxia: inability to coordinate muscle movements (walking, talking, self-care)
- Autonomic nervous system: regulates involuntary functions
- Axon: carries impulses AWAY from the cell body. Dendrite: carries impulses TOWARD the cell body
- Babinski reflex (sign): toe reflex; in adults indicates abnormality of motor pathways from the cortex
- Clonus: rapid alternating contraction and relaxation of a muscle
- Delirium: acute confused state starting with disorientation; can progress to altered consciousness, permanent brain damage and death if not treated early
- Flaccidity: no muscle tone, limp
- Parasympathetic nervous system: active in nonstressful conditions, controls mostly visceral functions
- Position sense (proprioception): knowing where body parts are without looking
- Reflex: automatic response to a stimulus
- Rigidity: increased tone at rest with resistance to passive stretch
- Romberg test: cerebellar test (seated or standing); inability to maintain position for 20 seconds is positive
- Spasticity: sustained increased muscle tension when passively stretched
- Sympathetic nervous system: excitatory “fight or flight”
- Vertigo: illusion of movement (self or surroundings), usually rotation
I. Anatomic and Physiologic Overview
- CNS: brain and spinal cord. Peripheral nervous system: cranial nerves, spinal nerves, autonomic nervous system. Function: motor, sensory, autonomic, cognitive and behavioral control
- Neuron: dendrites, cell body, axon (myelin speeds conduction); clusters of cell bodies are ganglia or nuclei; a functional cluster is a center (respiratory center). Glial cells (50 times more numerous) support and nourish neurons
Neurotransmitters (Table 60-1): released into the synapse, bind postsynaptic receptors, excite or inhibit, then are destroyed by enzymes or reabsorbed.
- Acetylcholine: major PARASYMPATHETIC transmitter; usually excitatory (vagal slowing of the heart is inhibitory); impaired binding in MYASTHENIA GRAVIS
- Serotonin: inhibitory; mood, sleep, inhibits pain
- Dopamine (substantia nigra, basal ganglia): usually inhibitory; behavior and FINE MOVEMENT; DECREASED in PARKINSON disease
- Norepinephrine: major SYMPATHETIC transmitter; usually excitatory; mood and activity
- GABA: inhibitory
- Enkephalins, endorphins: pleasurable sensation, inhibit pain
- PET and SPECT can detect neurotransmitter changes (dopamine in Parkinson disease)
A. Brain
- About 2% of body weight (1,400 g young adult, 1,200 g older adult); cerebrum, brain stem, cerebellum
- Cerebrum: gyri and sulci; longitudinal fissure divides hemispheres joined by the CORPUS CALLOSUM (transfers information between sides); outer gray matter cortex (cell bodies), inner white matter (myelinated tracts)
Lobes:
- FRONTAL (largest): concentration, abstract thought, memory, motor function; BROCA AREA (left hemisphere, motor control of SPEECH); affect, judgment, personality, inhibitions
- PARIETAL: sensory analysis; body position in space, size and shape discrimination, right-left orientation
- TEMPORAL: auditory reception; memory of sound; understanding of language and music
-
OCCIPITAL: VISUAL interpretation and memory
- Left hemisphere is dominant in right-handers (and some left-handers) for verbal, linguistic, arithmetic and analytic functions; nondominant side handles geometric, spatial, visual, pattern and musical functions
- CN I and II nuclei are in the cerebrum
- THALAMUS: relay station for ALL sensation EXCEPT SMELL; memory, sensation and pain impulses pass through it
- HYPOTHALAMUS: connects to the posterior pituitary; regulates pituitary hormones (metabolism, reproduction, stress response, urine production), fluid balance, TEMPERATURE (vasoconstriction or dilation), hunger and appetite, sleep-wake cycle, BP, aggression, sexual behavior, emotional responses; controls the autonomic nervous system; optic chiasm and mammillary bodies nearby
- BASAL GANGLIA: control fine motor movements of hands and lower extremities
Brain stem:
- Midbrain: auditory and visual reflex center; CN III and IV
- Pons: bridge between cerebellar halves and between medulla and midbrain; CN V to VIII; helps regulate respiration
- Medulla: motor and sensory fibers mostly CROSS (decussate) here; CN IX to XII; reflex centers for RESPIRATION, BP, HEART RATE, coughing, vomiting, swallowing, sneezing; RETICULAR FORMATION (arousal, sleep-wake) begins here
Cerebellum: behind midbrain and pons, below the occipital lobe; integrates sensory input for smooth coordinated movement, fine movement, BALANCE and proprioception.
B. Protective structures
- Skull bones (frontal, temporal, parietal, occipital, sphenoid) joined at sutures; anterior fossa (frontal lobe), middle fossa (temporal lobe), posterior fossa (cerebellum and brain stem)
- Meninges:
- DURA MATER: tough outer layer; folds are the falx cerebri (between hemispheres), TENTORIUM (between occipital lobe and cerebellum) and falx cerebelli. Increased pressure can push brain tissue against or around these folds (HERNIATION). Potential EPIDURAL space (above dura) and SUBDURAL space (below dura) can fill with blood or abscess
- ARACHNOID: thin, weblike; SUBARACHNOID space below it holds CSF; ARACHNOID VILLI absorb CSF into venous sinuses; blood or bacteria can block them and cause COMMUNICATING HYDROCEPHALUS
- PIA MATER: thin inner layer hugging the brain
C. Cerebrospinal fluid
- Clear, colorless; made by the CHOROID PLEXUS in the ventricles; about 500 mL/day produced; 125 to 150 mL in the system at a time
- Flow: lateral ventricles, foramen of Monro, third ventricle, aqueduct of Sylvius, fourth ventricle, subarachnoid space, absorbed by arachnoid villi. Blockage within the ventricles causes OBSTRUCTIVE hydrocephalus
- Normal: clear, specific gravity 1.007, minimal WBCs, NO RBCs; tested for protein, glucose, cells, electrolytes, immunoglobulins, bacteria; obtained by lumbar puncture or ventricular catheter
D. Cerebral circulation
- Brain stores no nutrients; receives 15% of cardiac output (750 mL/min)
- Arteries and veins do not run in parallel; collateral flow through the CIRCLE OF WILLIS; vessel walls have 2 layers instead of 3 (rupture more easily)
- Anterior circulation from the internal carotids (anterior and middle cerebral arteries); posterior from vertebral arteries joining as the BASILAR artery, which divides into posterior cerebral arteries; anterior and posterior communicating arteries complete the circle
- Bifurcations of the circle of Willis are common ANEURYSM sites; rupture causes hemorrhagic stroke
- Veins drain into dural sinuses and then the internal jugular veins; cerebral veins have NO VALVES (depend on gravity and BP)
Blood-brain barrier: tight junctions of capillary endothelium (with astrocytes) block many dyes, drugs and antibiotics; altered by trauma, cerebral edema and hypoxemia (affects drug choice).
E. Spinal cord
- Continuous with the medulla; about 45 cm (18 inches); from the foramen magnum to the lower border of L1, ending as the CONUS MEDULLARIS; nerve roots below L2 form the CAUDA EQUINA
- H-shaped gray matter: ANTERIOR horns are MOTOR (voluntary and reflex activity); POSTERIOR horns are SENSORY (relay); thoracic LATERAL horns give rise to SYMPATHETIC fibers
- Ascending tracts: posterior columns (fasciculus cuneatus and gracilis) carry deep touch, pressure, VIBRATION and POSITION from the same side and cross in the medulla; spinocerebellar tracts (muscle spindle input, uncrossed to the cerebellum); SPINOTHALAMIC tracts carry PAIN and TEMPERATURE (and fine touch, vibration) and cross in the cord to the thalamus
- Descending tracts: anterior and lateral CORTICOSPINAL tracts carry VOLUNTARY motor impulses and cross in the medulla; vestibulospinal (uncrossed; autonomic functions and involuntary muscle control); corticobulbar (voluntary head and face muscles, crosses in the brain stem); rubrospinal and reticulospinal (involuntary movement)
- Vertebral column: 7 cervical, 12 thoracic, 5 lumbar, sacrum (5 fused), coccyx; discs between vertebrae except C1-C2, sacral and coccygeal
F. Peripheral nervous system
Cranial nerves (Table 60-2): sensory I, II, VIII; motor III, IV, VI, XI, XII; mixed V, VII, IX, X.
| CN | Function | How to test |
|---|---|---|
| I Olfactory | Smell | Each nostril with various scents |
| II Optic | Vision | Acuity and visual fields |
| III Oculomotor | Pupil constriction, eyelid elevation, most eye movement | Pupillary light reaction; open and close eyelids |
| IV Trochlear | Downward, inward eye movement | Down and in gaze |
| V Trigeminal | Chewing; sensation of face and neck | Clench jaw while palpating; light touch, pain, temperature on face |
| VI Abducens | LATERAL eye movement | Eye movement in all directions |
| VII Facial | Facial muscles; taste on anterior 2/3 of tongue | Raise eyebrows, smile, show teeth, puff cheeks; taste |
| VIII Acoustic | Hearing (and balance) | Hearing |
| IX Glossopharyngeal | Swallowing; taste on posterior 1/3 | Say “ah,” yawn (soft palate rises); GAG; swallowing; taste |
| X Vagus | Swallowing and speaking | Swallow and speak; note HOARSENESS |
| XI Accessory | Shoulder muscles | SHRUG shoulders against resistance |
| XII Hypoglossal | Tongue movement and strength | Protrude tongue; push tongue against cheek |
Spinal nerves: 31 pairs (8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal). DORSAL roots are SENSORY (dermatomes); VENTRAL roots are MOTOR.
G. Autonomic nervous system
- Regulates heart, lungs, vessels, digestive organs, glands; maintains homeostasis; regulated by spinal cord, brain stem and the HYPOTHALAMUS (major subcortical center)
- Most organs receive both divisions
| Structure | Parasympathetic | Sympathetic |
|---|---|---|
| Pupil | Constricted | DILATED |
| Heart rate and force | Decreased | INCREASED |
| Coronary and skeletal muscle vessels | Dilated | |
| Skin and abdominal vessels | CONSTRICTED (cool skin, blood shunted to vital organs) | |
| Blood pressure | Decreased | Increased |
| Bronchioles | Constricted | DILATED |
| Peristalsis | Increased | DECREASED |
| GI sphincters | Relaxed | Contracted |
| Saliva | Thin, watery | Thick, viscid |
| Liver glycogen to glucose | Increased | |
| Bladder wall / sphincter | Contracted / relaxed (voiding) | Relaxed / contracted (retention) |
| Sweating, goose flesh | Increased | |
| Adrenal medulla | Releases epinephrine and norepinephrine |
- SYMPATHETIC (thoracolumbar, T1 to L2-L3; chain of 22 linked ganglia): fight-or-flight; norepinephrine (adrenergic). Sympathetic storm: altered consciousness, vital signs, diaphoresis and agitation after traumatic brain injury
- PARASYMPATHETIC (craniosacral: brain stem and below L2): dominant in nonstress conditions; acetylcholine (cholinergic)
- Celiac (solar) plexus serves adrenals, kidneys, liver, spleen, stomach, duodenum
H. Motor and sensory pathways
- Motor cortex in the frontal lobe; fibers converge in the INTERNAL CAPSULE (a small lesion here causes more paralysis than a larger cortical lesion); cross in the MEDULLA to the anterior horn
- UPPER motor neurons (cortex, cerebellum, brain stem; entirely within the CNS) modulate LOWER motor neurons (anterior horn or cranial nerve nuclei, axons in peripheral nerves to muscle)
Table 60-4:
| Upper motor neuron lesion | Lower motor neuron lesion |
|---|---|
| Loss of voluntary control | Loss of voluntary control |
| INCREASED tone | DECREASED tone |
| SPASTIC paralysis | FLACCID paralysis |
| NO atrophy | ATROPHY |
| HYPERACTIVE and abnormal reflexes (Babinski) | ABSENT or decreased reflexes |
- UMN lesions: stroke, spinal cord injury; hyperactive DTRs, diminished superficial reflexes, Babinski, leg spasms below the injury. Hemiplegia (arm and leg on one side; internal capsule lesion causes OPPOSITE-side weakness); paraplegia (both legs); tetraplegia or quadriplegia (all four limbs)
- LMN lesions: damage between cord and muscle; flaccid paralysis and atrophy; can recover if the nerve heals, but not if anterior horn cells are destroyed; causes include trauma, polio, toxins, vascular disease, tumors, HERNIATED DISCS
- Coordination: cerebellum adjusts opposing muscle groups for smooth, sustained movement; basal ganglia plan movement and inhibit unwanted activity
- Cerebellar damage: loss of tone, weakness, fatigue; abnormal flexion or extension posturing; FLACCIDITY after abnormal posturing signals severe impairment and may herald brain death
- Basal ganglia damage: NOT paralysis, but RIGIDITY, posture problems, trouble starting or changing movement, involuntary movements: coarse TREMORS (distal upper extremities), ATHETOSIS (slow writhing), CHOREA (jerky purposeless movements and grimacing). Examples: Parkinson and Huntington diseases
- Sensory: pain and temperature fibers cross IMMEDIATELY in the cord (spinothalamic) to the thalamus; touch fibers ascend before crossing; position and vibration ascend UNCROSSED in the posterior columns to the medulla, then cross
- Thalamus integrates all sensation except smell and relays to the parietal lobe
- Sensory losses: destroyed sensory nerve causes total loss in its distribution; posterior root lesions cause pain referred to their area; complete cord destruction causes complete anesthesia below the level; posterior column damage causes loss of position and vibration with pain and temperature intact; a central cord cyst causes loss of pain at that level (crossing fibers cut); thalamic or parietal lesions impair touch, pain, temperature and proprioception
II. Health History
- Observe appearance, mental status, posture, movement and affect during the interview; use yes-or-no questions, records or witnesses as needed
- Onset, character, severity, location, duration, frequency; associated complaints; aggravating and relieving factors; progression, remission, exacerbation; family history
Common symptoms:
- Pain: acute (brain hemorrhage, disc disease, trigeminal neuralgia) or chronic (degenerative conditions such as MS)
- Seizures: abnormal cortical discharge altering sensation, behavior, movement, perception or consciousness; from a blank stare to a tonic-clonic seizure; isolated (fever, alcohol or drug withdrawal, hypoglycemia) or the first sign of a brain lesion
- Dizziness and vertigo: dizziness is common in older adults; about 50% of dizzy patients have VERTIGO (usually vestibular dysfunction; can cause disorientation, loss of balance, nausea and vomiting)
- Visual disturbances: from the eye (cataract), the pathway (tumor) or the cortex (stroke); nystagmus (MS) causes diplopia
- Muscle weakness: sudden (stroke) or progressive (ALS)
- Abnormal sensation: fall and injury risk
History also includes genetics (Chart 60-1: autosomal dominant Huntington disease, neurofibromatosis with cafe-au-lait spots and axillary freckles, familial Alzheimer disease, myotonic dystrophy; autosomal recessive Friedreich ataxia, Canavan; X-linked Duchenne muscular dystrophy, fragile X; predisposition for ALS, epilepsy, neural tube defects, Parkinson disease, Tourette syndrome), trauma, falls, alcohol, medications and drugs.
III. Physical Assessment
Five components: consciousness and cognition, cranial nerves, motor system, sensory system, reflexes. Priorities depend on the problem: motor, sensory and reflexes for spinal injury; cranial nerves and LOC for a comatose patient.
A. Consciousness and cognition
- Describe findings specifically and nonjudgmentally; avoid labels like “inappropriate” or “demented”
- Mental status: appearance, dress, grooming, hygiene, posture, gestures, facial expression; orientation to time, place and person; immediate and remote memory
- Intellectual function: repeat 7 digits forward and 5 backward; count backward from 100 or SERIAL 7s; interpret PROVERBS (abstract reasoning); similarities (mouse and dog); judgment (locked out without a key). Frontal damage may look intact until these are tested
- Thought content: spontaneous, clear, relevant, coherent; fixed ideas, illusions, preoccupation with death, hallucinations, paranoia need evaluation
- Emotional status: affect (natural, irritable, anxious, flat, euphoric), mood swings, match of affect to content and of verbal to nonverbal cues
- Language: comprehension, reading, writing, copying a figure. APHASIA (Table 60-5): auditory receptive (temporal lobe); visual receptive (parietal-occipital); expressive speaking (inferior-posterior frontal, Broca); expressive writing (posterior frontal)
- Impact on lifestyle and roles
- LEVEL OF CONSCIOUSNESS is the MOST SENSITIVE indicator of neurologic function: alertness and ability to follow commands; if not alert, note eye opening, verbal and motor responses and what stimulus is needed (use noxious stimuli first, then painful stimuli if no response). With decreased LOC, motor and cranial nerve assessments become the priority
B. Cranial nerves
Assessed with decreased LOC, brain stem disease or peripheral nerve disease; compare right and left (Table 60-2).
C. Motor system
- Gait and posture; muscle size and symmetry; atrophy; involuntary movements (tremors, tics); tone at rest and with passive movement (SPASTICITY, RIGIDITY, FLACCIDITY)
- Strength against resistance, comparing sides; PRONATOR DRIFT (arms out, palms up; drifting and pronation reveals subtle weakness)
- Muscle strength scale (record on a stick figure, proximal and distal):
| Grade | Meaning |
|---|---|
| 5 | Full strength against gravity and full resistance (normal) |
| 4 | Against gravity and moderate resistance (slight weakness) |
| 3 | Just overcomes gravity, no resistance (moderate weakness) |
| 2 | Moves but cannot overcome gravity (severe weakness) |
| 1 | Palpable contraction, no movement (very severe weakness) |
| 0 | No movement |
- Coordination (cerebellum, basal ganglia): rapid alternating movements (pat thighs, pronate and supinate, touch each finger to thumb); point-to-point (finger to examiner’s finger to nose); HEEL down the opposite SHIN; ataxia; tremors
- ROMBERG: feet together, arms at sides, eyes open then CLOSED for 20 seconds, examiner standing close; slight sway is normal; LOSS OF BALANCE is a POSITIVE test. Also hopping, knee bends, heel-to-toe walking
D. Sensory system
- Subjective; eyes closed; reassure; follow dermatomes
- Light touch with cotton or fingertip, compare proximal to distal and side to side
- Pain with the sharp and dull ends of a broken swab or tongue blade (NOT a safety pin, which breaks the skin); usually reserved for patients who cannot discriminate touch. Pain and temperature travel together, so temperature testing is usually unnecessary
- Vibration with a 128 or 256 Hz tuning fork on the great toe or thumb joint, moving up if absent
- Position sense: move the great toe or index finger up or down with eyes closed. Vibration and position are often lost together
- Two-point discrimination; EXTINCTION (simultaneous touch on both sides felt on only one side)
- STEREOGNOSIS: identify an object (key, coin) by touch; inability is tactile agnosia (astereognosis)
- Agnosia sites (Table 60-6): visual (occipital), auditory (temporal), tactile (parietal), body parts (parietal)
- Peripheral neuropathy and spinal cord injury follow dermatomes; brain lesions can affect an entire side
E. Reflexes
- Deep tendon reflexes with a reflex hammer; slightly stretched tendon; relaxed patient; equal force; SYMMETRY matters more than the absolute response
- Reinforcement (Jendrassik): lock fingers and pull apart to bring out leg reflexes; clench jaw or press heels down for arm reflexes
- Ankle jerks may be normally absent in older adults
DTR grading (Chart 60-2):
- 0: no response
- 1+: diminished (hypoactive)
- 2+: NORMAL
- 3+: increased (may be normal)
- 4+: hyperactive (hyperreflexia)
-
Recorded on a stick figure or as a fraction (2/4)
- Biceps: thumb on the tendon of the slightly flexed elbow; elbow flexion
- Triceps: arm flexed and hanging; strike 2.5 to 5 cm above the elbow; elbow extension
- Brachioradialis: forearm on lap; strike 2.5 to 5 cm above the wrist; flexion and supination
- Patellar: below the patella; knee extension
- Achilles: dorsiflex the foot; plantar flexion (kneel on a chair if the patient cannot relax)
- CLONUS: abrupt dorsiflexion causes repeated beats; a few beats with hyperactive reflexes is not pathologic, but SUSTAINED clonus always indicates CNS disease
- Superficial reflexes graded present (+) or absent (-): corneal, gag and plantar are most often tested
- Corneal (cotton wisp on the outer sclera, blink): loss after stroke or brain injury requires EYE PROTECTION and lubrication
- Gag (touch each side of the posterior pharynx): absence after stroke requires swallow evaluation to prevent ASPIRATION
- Pathologic reflexes: BABINSKI (stroke the lateral sole; toes fan and extend instead of curling) indicates corticospinal disease; normal in newborns, serious in adults. Recorded as an upward arrow. Also suck, snout, palmar grasp and palmomental reflexes (progressive degeneration)
IV. Gerontologic Considerations
- Do not attribute dysfunction to aging without investigation; localized weakness is always disease
- Structural: neuron loss, fewer synapses and neurotransmitters, slower conduction and response; smaller brain, larger ventricles; less cerebral blood flow; less efficient temperature regulation; myelin loss in peripheral nerves; vision, hearing, taste and smell decline; vestibular, cerebellar and proprioceptive degeneration (balance); DTRs decreased or absent; less stage IV sleep; slower autonomic responses; reduced pupil responses
- Motor: less muscle bulk (hand atrophy), less strength and agility, slower reaction, slow wide-based gait, FALL risk
- Sensory: dulled touch, poor body-position awareness from the feet; glare sensitivity, reduced peripheral vision, slow dark adaptation (NIGHTLIGHTS, familiar furniture arrangement); hearing loss causes confusion and isolation; reduced taste and smell (weight loss, cannot smell gas leaks or fire: smoke and CO detectors)
- Temperature and pain: feel cold more easily (extra covers, warmer room); reduced pain perception, so use hot and cold packs cautiously (burns, frostbite) and take complaints like chest or abdominal pain seriously; diabetic and postherpetic neuropathies are common
- Mental status: processing slows but memory, language and judgment remain intact; a change in mental status is NEVER normal aging. DELIRIUM (acute, often from infection, drug reaction, dehydration; screen with the Confusion Assessment Method) must be told apart from DEMENTIA (chronic, irreversible)
- Nursing: assess impact on ADLs; fall prevention; teaching with good light without glare, contrasting colors, large print; low-pitched clear voice (shouting makes it worse); unrushed, short, concrete sessions with reinforcement
V. Diagnostic Evaluation
- Explain purpose and expectations; premenopausal women should use contraception before and for several days after contrast studies; breastfeeding women stop for the time the nuclear medicine department advises; watch trends
| Test | What it does | Nursing |
|---|---|---|
| CT scan | X-ray cross-sections; tumors, infarction, HEMORRHAGE, ventricular shift, atrophy; CT angiography; usually done first without then with contrast; quick, painless, small radiation dose | Lie still; relaxation or sedation; if contrast: ask about IODINE or SHELLFISH allergy, check KIDNEY function, IV line, usually NPO 4 hours; watch for allergic reaction and kidney changes; push fluids afterward |
| MRI | Magnetic field and radio waves; earlier, clearer detection; tumor, stroke, MS; no ionizing radiation; may take an hour or more (limited in emergencies); MRA shows vessels without arterial contrast; DWI, PWI, FLAIR | Screen for metal (work with metal fragments, aneurysm clips, orthopedic hardware, heart valves, IUDs), cardiac devices, cochlear implants (inactivated); remove all metal and credit cards; remove FOIL-BACKED patches (burns); NO metal equipment in the room (oxygen tanks, IV poles, wheelchairs, stethoscopes become projectiles); must lie flat in a narrow tube; loud thumping; claustrophobia (sedation or open MRI, lower image quality); can talk by microphone |
| PET | Inhaled or injected positron-emitting isotope; brain METABOLISM (brain uses 80% of body glucose); Alzheimer disease, tumors, seizure foci, stroke, tumor vs necrosis, mental illness | Explain inhalation and sensations (dizziness, lightheadedness, headache); relaxation |
| SPECT | Radionuclide perfusion study with a gamma camera; stroke location and size BEFORE CT shows it, seizure foci, tumor progression, perfusion before and after surgery | Education; contraindicated in PREGNANCY and breastfeeding; monitor for allergic reaction; accompany for transport |
| Cerebral angiography | Contrast injected through a femoral or radial artery catheter; aneurysms, AVMs, vessel patency, collateral circulation; coils can be placed | BEFORE: BUN and creatinine, hydration (clear liquids allowed), void, MARK peripheral pulses; expect warmth in the face and a metallic taste. AFTER: neuro checks for embolism or dissection (new LOC change, one-sided weakness, motor or sensory deficits, speech changes); site for bleeding and hematoma; distal pulses, color and temperature; fluids; allergic reaction; hypotension if vasodilators were used for radial access |
| Myelography | Contrast injected by lumbar puncture into the spinal subarachnoid space; tumors, cysts, herniated discs; often followed by CT (largely replaced by CT and MRI) | AFTER: HOB 30 to 45 degrees, bed rest 4 to 24 hours; liberal fluids (prevents headache); VS and ability to void; complications nausea, vomiting, headache, fever, stiff neck, seizures, paralysis, LOC changes |
| Carotid flow studies, transcranial Doppler | Noninvasive ultrasound and Doppler of carotid, orbital and intracranial vessels; higher velocity means stenosis; TCD detects VASOSPASM after subarachnoid hemorrhage and helps confirm brain death | Explain; gel on the transducer over the neck and eye orbits; can be done at the bedside |
| EEG | Scalp electrodes record cerebral electrical activity; seizures, coma, organic brain syndrome, tumors, abscess, clots, infection; supports BRAIN DEATH determination; may use hyperventilation (3 to 4 minutes) or flashing light; sleep EEG; depth electrodes for surgical planning | May be SLEEP-DEPRIVED the night before; WITHHOLD anticonvulsants, tranquilizers, stimulants and depressants 24 to 48 hours (check orders); no coffee, tea, chocolate or cola, but do NOT skip the meal (low glucose alters waves); 45 to 60 minutes (sleep EEG 12 hours); not an electric shock and not a treatment; lie quietly; no sedation (lowers seizure threshold); water-soluble paste (shampoo) or collodion glue (acetone) |
| EMG | Needle electrodes in muscle; neuromuscular disorders and myopathies; tells neuropathy from other weakness | Feels like an IM injection; muscles may ache afterward |
| Nerve conduction studies | Stimulate a peripheral nerve and record the action potential; peripheral neuropathy; often part of EMG | |
| Evoked potentials | Visual (checkerboard or flashing light), brain stem auditory (clicks; brain stem lesions, brain death), somatosensory (spinal cord and peripheral conduction, intraoperative monitoring, MS) | Relax and stay perfectly still |
| Lumbar puncture | Needle into the lumbar subarachnoid space at L2-L3, L3-L4 or L4-L5 (cord ends at L1); obtain CSF, measure or reduce pressure, detect blood, give intrathecal drugs | Patient must be relaxed (anxiety alters pressure); RISKY with an INTRACRANIAL MASS (herniation through the foramen magnum); send specimens immediately |
CSF analysis: should be clear and colorless; pink or bloody may mean subarachnoid hemorrhage (bloody from local trauma clears as more fluid drains).
Post-lumbar puncture headache:
- Hours to days later; throbbing bifrontal or occipital, dull and deep; WORSE sitting or standing, RELIEVED lying down
- Cause: CSF leak through the needle track depletes CSF so the brain loses support and venous sinuses stretch when upright
- Prevent with a small (22-gauge) needle; treat with analgesics, HYDRATION, CAFFEINE, lying SUPINE
- Other complications: rare herniation, epidural abscess or hematoma, meningitis; voiding problems, slight fever, backache, stiff neck
Home and transitional care: many tests are outpatient, so teach patient and family precautions and complications; arrange transport and monitoring; follow up by phone.
High-Yield Numbers
- Brain 2% of body weight; 15% of cardiac output (750 mL/min); uses 80% of body glucose (per text)
- CSF made 500 mL/day; 125 to 150 mL in circulation; specific gravity 1.007; no RBCs
- Spinal cord 45 cm, ends at L1; LP at L2-L3 to L4-L5
- 31 spinal nerve pairs (8, 12, 5, 5, 1); 12 cranial nerves (sensory I, II, VIII; motor III, IV, VI, XI, XII; mixed V, VII, IX, X)
- Glial cells 50 times neurons
- Romberg 20 seconds
- Repeat 7 digits forward, 5 backward
- Strength 0 to 5; DTRs 0 to 4+, 2+ normal
- Tuning fork 128 or 256 Hz
- Post-myelogram HOB 30 to 45 degrees, bed rest 4 to 24 hours
- Hold seizure and CNS drugs 24 to 48 hours before EEG; EEG 45 to 60 minutes, sleep EEG 12 hours
- NPO 4 hours before contrast CT
- 22-gauge needle reduces post-LP headache
Priority Nursing Actions and Red Flags
- LOC is the most sensitive indicator; any change is reported promptly
- Unilateral motor or sensory changes after angiography: suspect embolism; check the site and marked pulses
- No metal in the MRI room; remove foil patches; screen implants and devices
- Contrast: iodine or shellfish allergy, kidney function, fluids afterward
- Lumbar puncture is dangerous with suspected increased ICP or a mass
- Positional headache after LP: lie flat, fluids, caffeine
- Loss of corneal reflex: protect and lubricate the eye
- Absent gag: NPO until swallow evaluation (aspiration)
- Sustained clonus and Babinski in an adult indicate CNS disease
- New confusion in an older adult is delirium until proven otherwise
- Older adults: caution with heat and cold packs; nightlights; fall prevention
Medications
No primary drug therapy in this chapter. Drug-related points:
- Hold anticonvulsants, tranquilizers, stimulants and depressants 24 to 48 hours before EEG (per order); avoid caffeine before EEG; no sedation for EEG
- Sedation may be used for CT or MRI in claustrophobic or agitated patients (monitor)
- Caffeine and analgesics treat post-lumbar puncture headache
- Iodinated contrast: allergy and kidney precautions
Related
- nsg210-hinkle-ch61-neurologic-dysfunction (LOC, GCS, ICP, seizures, headache)
- nsg210-hinkle-ch63-neurologic-trauma (spinal cord injury)
- nsg210-hinkle-ch64-neuro-infections-autoimmune (MS)
- nsg210-hinkle-ch65-degenerative-neuro (Parkinson disease)
- nsg210-hinkle-ch35-musculoskeletal-assessment (MRI safety, EMG)
- INDEX