Neurologic Diseases

Alexander Fay

Kristin P. Guilliams

Christina A. Gurnett

NEUROLOGIC EXAMINATION

Head Circumference

Always document the occipitofrontal circumference (OFC) in children <2 years of age and in those you are seeing for the first time. The rule of 3s and 9s (birth: 35 cm; 3 months: 40 cm; 9 months, 45 cm; 3 years, 50 cm; 9 years to adult, 55 cm) is helpful to remember the approximate OFC appropriate for age.
Document parental OFCs if there is a concern for macrocephaly or microcephaly; benign familial macrocephaly is a leading cause of macrocephaly.
Posterior fontanelle closes 1-3 months postnatally. Anterior fontanelle closes 7-19 months postnatally in most children. May be enlarged and have delayed closure in trisomy 21, hypothyroidism, and achondroplasia.

General Examination

Be sure to assess the following: vital signs, including respiratory pattern; dysmorphic features, including ambiguous genitalia and sacral anomalies; the pulmonary, cardiac, and gastrointestinal systems; cutaneous manifestations (look for such features such as café au lait macules, neurofibromas, ash leaf spots, hypomelanotic macules, whorled lines); spine; and extremities.

Mental Status

Level of consciousness and response to stimulus (e.g., awake, asleep, opens eyes to voice, grimace to sternal rub, unresponsive)
In infants, assess visual fixation/tracking, and if irritable, whether consolable with pacifier, swaddling, etc.
Language
Assess expressive language (fluency), receptive language (following commands), and ability to repeat
Orientation to Person, Place, Time (Year, Month, Day), Situation
Higher Cognitive Assessment (Must be Appropriate for Developmental Level)
Registration and Recall of Three Words (Chair, Candle, Dog)
Ability to name colors, animals
- Counting or basic calculations: 24-36 months “Count as high as you can,” 4-8 years “Count backwards from 20,” 9-13 “Count backwards from 50 by 3’s,” >13 “Count backwards from 100 by 7’s”

Cranial Nerves

Olfactory: use nonnoxious stimuli, such as coffee or vanilla
- Performance is mandatory in cases of facial trauma.
Optic nerve
- Pupillary examination (use actual size and change [i.e., 4/4 down to 2/2 brisk])
- Funduscopic examination—evaluate for:
  - Papilledema (takes ˜24 hours to develop)
  - Hemorrhage (most sensitive clinical indicator of subarachnoid hemorrhage, easier to demonstrate with pupillary dilation)
  - Venous pulsations (present when intracranial pressure [ICP] is below 180 mm; note that ˜20% of normal people do not have venous pulsations)
- Visual fields, visual acuity: this helps differentiate between optic neuritis and papilledema because there is little change in fields or acuity with papilledema. Red desaturation often occurs in optic neuritis and can be tested by comparing the intensity of a red object between two eyes, or using Ishihara color plates. Bitemporal hemianopsia indicates chiasmatic lesion; homonymous hemianopsia or quadrantanopsia indicates lesion of optic radiations or occipital cortex.
- Relative afferent pupillary defect: this is brought out by the swinging flashlight test, which documents abnormality in afferent arc of pupillary light response proximal to dorsal midbrain (i.e., lesion in the macula, retina, optic nerve or tract, brainstem; it is generally not seen with cataracts).
- Red reflex: hold the ophthalmoscope at arm’s length in a darkened room and examine for equivalence in color, intensity, clarity, and absence of opacities or white spots; it will be lighter than usual in pigmented individuals or absent in retinoblastoma. If abnormal, examine dilated pupils or refer to ophthalmology.
Cranial nerves (CNs III, IV, and VI)
- Extraocular movements: using H-shaped path to isolate muscles, pay particular attention to nystagmus (end-gaze nystagmus that extinguishes is normal, most often indicative of myopia), CN VI (lateral rectus), and CN III palsy (affecting the pupil) are often early signs of increased ICP.
- Conjugate gaze: examine whether light reflects identically from each iris; does alternating cover test uncover a latent esophoria (inward deviation) or exophoria (outward)? CN IV palsy causes hypertropia (elevation) and excyclotorsion of the affected eye, and the patient may tilt the head away from the affected eye to compensate.
Facial nerve (CN VII): assess facial symmetry; distinguish between upper motor neuron (UMN) and lower motor neuron (LMN) disease (i.e., if the whole face is weak, then it is likely LMN, but if only the lower face is weak, then it is UMN because of bilateral cortical input to the forehead)
CN VIII: head impulse test, Dix-Hallpike maneuver indicate peripheral lesion if positive, can help to exclude a central lesion. Hearing: test with Weber and Rinne (512-Hz tuning fork) to distinguish conductive and sensorineural hearing loss.
CNs IX and X: determine any changes in voice, palate elevation, gag reflex
CN XI: test shoulder elevation and head rotation
CN XII: check tongue movements and look for atrophy or fasciculations

Motor Examination

Assess muscle bulk, tone (appendicular and axial), and strength graded on the Medical Research Council (MRC) scale (0—no contraction, 1—contraction but no movement across joint, 2—movement across joint without gravity, 3—movement against gravity but not resistance, 4—movement against some resistance but not against examiner’s full force, 5—examiner cannot overcome patient force). In infants, hold under the arms and in ventral suspension to assess axial tone.
Assess adventitial movements (e.g., tics, chorea, dystonia).

Sensory Examination

Check four modalities (temperature/pinprick, vibration, light touch, joint position sense) and assess for hemisensory neglect with bilateral, simultaneous stimulation. Romberg maneuver tests for sensory ataxia.
Try to determine if deficits correlate with regions controlled by the nerve, plexus, root, cord, or cerebral cortex.

Deep Tendon Reflexes

Perform after the motor and sensory examinations because it relies on information gleaned from the motor and sensory exams (i.e., evidence of myopathy, neuropathy, weakness). Typically increased in CNS lesions, decreased in motor neuron and neuropathic disease, though can be decreased in acute spinal cord disease.
Grade on a Medical Research Council (MRC) scale (0—no reflex, which occurs faster in neuropathy compared with myopathy; 1—trace reflex; 2—normal reflex; 3—hyperreflexia, although not always pathologic; 4—hyperreflexia with clonus or spread that is always pathologic)
Perform special reflexes such as jaw jerk, trapezius, pectoralis, suprapatellar, abdominal, cremasteric, and ankle clonus as needed.

Primitive Reflexes

Palmar grasp: present from birth to 2-4 months
Plantar grasp: present from birth until 8 months
Moro: birth until 4-6 months
Tonic neck: birth until able to roll over (3-6 months)
Galant (ipsilateral trunk curvature with stroking along spine): birth until 2-3 months

Coordination

This is sometimes difficult to test in children, so look for velocity and accuracy on reaching for objects as a surrogate.
Use saccades (may overshoot or undershoot), finger-nose-finger, mirror, and heel-shin-heel movements.

Gait

Assess multiple parts of the neuraxis.
Look for stance, arm swing, evidence of hemiparesis with circumduction, weakness with heel or toe walking, and ataxia with tandem. Gower maneuver to assess for proximal weakness.

Coma Examination

Critical in all patients with an altered level of consciousness. Localize pathology to the bihemispheric, bithalamic, or reticular activating system (brainstem).
Mental status: document level of alertness, response to commands, regard, and speech.
Respiratory pattern: if intubated, determine whether the patient is breathing at a rate above that set by the ventilator and if breathing pattern is regular or irregular.
Pupillary reactivity
- Document size and reactivity; it may be necessary to use an otoscope to see poorly reactive pupils.
- Response is resistant to metabolic disturbance with the following exceptions:
  - Opiates: pinpoint
  - Anticholinergics and Sympathomimetics: fixed and dilated
  - Cholinergics: pinpoint
  - Hypoxia or hypothermia: midpoint and fixed
Extraocular movements
- Cold water calorics (20 mL in each ear) to activate the vestibulo-ocular reflex. Be sure there is no wax in the ears and that the tympanic membrane is intact. The doll’s (oculocephalic reflex) examination may be used if the cervical spine is stable.
Corneal reflex: tests afferent CN V and efferent CN VII
Facial grimace to noxious stimuli: nail bed pressure, nostril swab, or mandibular pull are preferable to sternal rub.
Cough/gag reflex
Response to pain
- Check for purposeful withdrawal, triple flexion (stereotyped response), decerebrate (extensor) or decorticate (flexor) posturing, or no response.
- Look for asymmetries.
Adventitial movements: note any tremor, myoclonus, or other involuntary movements.
Stretch reflexes and Babinski reflex
- Hyperreflexia often indicates structural lesion, whereas hyporeflexia often indicates metabolic or spinal cord injury (acutely). However, uremia, hypo/hyperglycemia, and hepatic coma may give focal signs with hyperreflexia.
- Look for asymmetries.

INTRACRANIAL HYPERTENSION (INCREASED INTRACRANIAL PRESSURE)

Clinical Signs and Symptoms

Bulging fontanel in infants
Decreased mental status
Early morning headache and nausea
Emesis without nausea
Cushing response (increased blood pressure, bradycardia, irregular respirations) is a late finding.
Meningismus
Asymmetric or sluggish pupillary response
Absent venous pulsations
Papilledema
Retinal/subhyaloid hemorrhages
Extraocular nerve palsies, such as CN VI palsy or setting-sun sign with paralysis of upgaze

Treatment

Consult with neurology and neurosurgery.
Do not lower blood pressure acutely (cerebral perfusion pressure = mean arterial pressure-intracranial pressure).
Elevate the head of the bed 30 degrees.
Order a “stat” head computed tomography (CT) scan. Order ventriculoperitoneal (VP) shunt series if patient has VP shunt.
Check electrolytes, complete blood count (CBC), and “stat” glucose.
Cardiac telemetry
Only use hyperventilation (PCO₂: <35 mm Hg) as a temporizing measure for impending herniation.
Mannitol (0.5-1 g/kg of 20% solution) works for interstitial edema but not well for cytotoxic edema (i.e., stroke); hypertonic saline may be considered.
Dexamethasone (0.25-0.5 mg/kg Q6 hours, maximum 16 mg/day) may improve vasogenic edema from brain tumor.
Treat hyperthermia aggressively with antipyretics, and closely monitor blood glucose.
Order a lumbar puncture (LP) if indicated (e.g., pseudotumor cerebri, meningitis) and no concern for obstruction or pressure differential between spinal column and ventricles [post-head CT in most cases].

SPINAL CORD COMPRESSION

Consider extensive differential diagnosis (trauma, tumor, transverse myelitis, infarct, vascular malformation, epidural abscess or hematoma, infection, disk protrusion, atlantoaxial subluxation).

Symptoms and Signs

Back pain (esp. focal)
Lower extremity and/or upper extremity weakness
Paresthesias or numbness with sensory level
Bowel and/or bladder constipation or incontinence
Early hypotonia, later hypertonia, and hyperreflexia
Loss of anal sphincter tone, cremasteric reflex, superficial abdominal reflexes

Treatment

Remember that cord compression (myelopathy) is an emergency.
Immobilize neck (cervical collar).
Stabilize airway but avoid hyperextension of the neck.
Spine plain films. Urgent MRI.
Insert a Foley catheter.
Consult trauma and/or neurosurgery (e.g., trauma, epidural abscess, mass).
Give methylprednisolone within 8 hours of injury: 30 mg/kg load over first 15-30 minutes followed by 5.4 mg/kg/hr for next 23 hours.
- Steroids may make diagnosis more difficult but do not delay for this reason.
- Steroid benefit based on adult trials remains controversial

ACUTE WEAKNESS

See Table 21-1.

Methods of Characterizing Weakness

Consider region (hemiplegia, diplegia, quadriplegia, facial involvement).
Consider time course (acute, subacute, or chronic).
Attempt to localize (central nervous system, spinal cord, nerve, neuromuscular junction, muscle).
Determine origin of weakness.
- UMN signs are hyperreflexia, spasticity, and Babinski sign; weakness may be more prominent in the upper extremity extensors and lower extremity flexors.
- LMN signs are hyporeflexia, hypotonicity, fasciculations, weakness, and atrophy.
Ataxia is primarily cerebellar but can also originate from hemispheric lesions.
Further consider systemic disease, especially sickle cell, cardiac defects, and coagulopathies.
History of trauma should prompt consideration of bleeding and arterial dissection.

TABLE 21-1 Evaluation of Acute Ataxia

Category of disease	Examples	Diagnostic testing
Ingestion/toxic	Anti-epileptic medications, sedatives	Urine and serum drug screen
Migraine variants	Benign paroxysmal vertigo, basilar migraine	History, normal MRI
Post-infectious	Acute cerebellar ataxia, acute cerebellitis, acute demyelinating encephalomyelitis (ADEM)	MRI, LP
Infectious	Meningitis, encephalitis, labyrinthitis	CSF culture, PCR for HSV-1,2, EMV, CMV, VZV; HIV
Demyelinating/autoimmune	MS, Sjogren’s, Behcet’s, neuromyelitis optica (NMO), Celiac	MRI brain, CSF oligoclonal bands, NMO Ab, ANA/ENA
Paraneoplastic	Opsoclonus-mycoclonus, NMDA-receptor encephalitis, GAD-65 encephalitis	Paraneoplastic Ab, urine HVA+VMA, CT abdomen, testicular U/S, PET scan
Malignancy	Posterior fossa tumors	Brain MRI with/without contrast
Vascular	Posterior circulation stroke, vertebral or basilar artery dissection, vasculitis	Brain MRI, MR angiography
Episodic ataxia	EA1: last minutes, myokymia, carbamazepine responsive EA2: hours-days, headache, acetazolamide responsive EA3-7: variable medication response	Acetazolamide or carbamazepine trial, genetic testing
Peripheral nerve (sensory ataxia)	Acute inflammatory demyelinating polyradiculoneuropathy (AIDP), Miller-Fisher syndrome	EMG/NCS, LP for albuminocytologic dissociation
Metabolic	Mitochondrial, urea cycle disorders, aminoacidopathies (MSUD), GLUT-1 deficiency, pyruvate dehydrogenase deficiency	Lactate/Pyruvate, CSF glucose, serum/CSF amino acids, urine organic acids, ammonia, acylcarnitine profile
Inner ear	Benign paroxysmal positional vertigo (BPPV), Ménière’s, vestibular Schwannoma
Electronystagmography, MRI
Psychogenic	Conversion disorder	Astasia-abasia gait
Epilepsy	Post-ictal state	EEG