Ataxia can result from a variety of lesions, including damage to the peripheral nerves, spinal cord, cerebellum, and cerebral hemispheres. One of the most common etiologies is drug intoxication, especially with alcohol, benzodiazepines, or phenytoin.
Findings of cerebellar dysfunction include nystagmus, staggering wide-based gait, and titubation. In addition, a sensory examination for light touch and pinprick, position, and vibration sense should be performed, because lower-extremity sensory impairment can cause ataxia.
In a patient with acute ataxia, the history and physical examination focus on excluding acute infectious etiologies, such as meningitis or encephalitis, lesions that result in increased intracranial pressure, such as hemorrhage and tumors, and toxic ingestions.
A common cause of ataxia in children younger than 6 years is acute cerebellar ataxia, a postinfectious phenomenon that often occurs about 2 weeks after a viral illness. The onset of ataxia is insidious and predominantly affects the gait, although dysmetria, nystagmus, and dysarthria can occur.
In children, the most common cause of intermittent ataxia is a migraine headache that involves the basilar artery. Besides ataxia, associated symptoms include blurred vision, visual field deficits, vertigo, and headache.
Chronic/progressive ataxia has an insidious onset and progresses slowly over weeks to months. The differential diagnosis consists of brain tumors, hydrocephalus, and genetic disorders.
The combination of ataxia, headache, irritability, and vomiting in a child younger than 6 years is characteristic of a brain tumor.
Hereditary causes of ataxia include spinocerebellar ataxias, of which there are over 30 types. Friedrich’s ataxia is common autosomal recessive ataxia, which usually manifests before 10 years of age. It is characterized by ataxia, nystagmus, dysarthria, kyphoscoliosis, cardiomyopathy, and absent deep tendon reflexes.
Patients with progressive ataxia require a thorough evaluation in the emergency department (ED). All patients are examined for signs of increased intracranial pressure, which in some cases can be severe enough to result in the threat of uncal herniation.
Ataxia is a disorder of intentional movement, characterized by impaired balance and coordination. It is usually due to a cerebellar disorder, which variably affects the trunk or extremities. Severe truncal ataxia is sometimes referred to as titubation. Ataxia affecting the extremities can result in a wide-based gait or can cause dysmetria, which is the tendency of the limbs to overshoot a target, with subsequent movements attempting to correct the overshoot.1–3
Ataxia is best classified as acute, episodic/intermittent, or chronic/progressive. Acute ataxia is usually acquired, whereas chronic/progressive usually is due to a congenital malformation or a hereditary or degenerative disorder, although brain tumors can also result in progressive symptoms.1–3
Ataxia can result from a variety of lesions, including damage to the peripheral nerves, spinal cord, cerebellum, and cerebral hemispheres. Lesions of the cerebellum can be further categorized as affecting the hemispheres, which results in ipsilateral limb hypotonia, tremor, and dysmetria, but spare speech. With walking, these patients tend to veer to the side of the lesion. Lesions of the midline vermis cause truncal ataxia or titubation, dysarthria, and gait abnormalities.1–3 Damage to the spinal cord can cause ataxia when the patient stands with the eyes closed, which is referred to as a positive Romberg sign (which tests proprioception). Patients with cerebellar ataxia have findings whether their eyes are open or closed.
Metabolic and systemic disorders can also cause ataxia. One of the most common etiologies is drug intoxication, especially with alcohol, benzodiazepines, or antiepileptic drugs.2–5
True ataxia must be distinguished from problems with similar neurologic manifestations. Vestibular disorders can cause vertigo, a sensation of abnormal movement or spinning that can cause a severe gait disturbance, nausea, and vomiting. Vertigo is often accompanied by nystagmus. Myopathies can be confused with ataxia, as can peripheral neuropathies. On physical examination, myopathies are characterized by muscle weakness, whereas peripheral neuropathies are accompanied by decreased reflexes. Chorea is a disorder characterized by involuntary movements and incoordination. It is distinguished from ataxia in that it occurs at rest, whereas ataxia is manifested during intentional movement.
Vital signs and a thorough physical examination should be performed. Any abnormalities such as bradycardia, hypertension, and an abnormal breathing pattern (Cushing’s triad) should be recognized as being a sign of increased intracranial pressure and treated immediately with bag-mask ventilation while preparing for rapid sequence intubation.
Findings of cerebellar dysfunction include nystagmus, staggering, wide-based gait, titubation, and speech abnormalities. Specific neurologic tests include the following:
Finger to nose with eyes closed (to look for intention tremor)
Finger to nose to (examiner’s) finger; dysmetria is poor coordination of voluntary movements, and results in under- or overshooting the target (tests cerebellar integrity when limb strength and sensation is intact)
Heel-to-shin maneuvers (test cerebellar integrity when limb strength and sensation are intact)
Rapid alternating hand movements—difficulty is termed dysdiadochokinesia (tests cerebellar function)
Heel and toe walking (with hemispheric lesions there is a tendency to veer in one direction)
Tandem gait (with hemispheric lesions there is a tendency to veer in one direction)
Walking in a circle (with hemispheric lesions there is a tendency to veer in one direction)1,2
In addition, a sensory examination for light touch and pinprick, position, and vibration sense should be performed because lower-extremity sensory impairment can cause ataxia.
Other findings to check for include eye findings such as nystagmus, opsoclonus (neuroblastoma), or papilledema; neck findings including meningismus (central nervous system [CNS] infection) or an ipsilateral head tilt (posterior fossa tumor); and ear findings including otitis media, and hearing loss (labyrinthitis).2
For diagnostic purposes, it is useful to categorize ataxia as acute, intermittent, or chronic/progressive (Table 54-1).
Acute Postinfectious/immune mediated Acute cerebellar Myoclonic encephalopathy of infancy (opsoclonus/myoclonus) Guillain–Barré/Miller–Fisher syndromes Tick paralysis Acute demyelinating encephalomyelitis (ADEM) Posttraumatic Hematoma Mass Vertebrobasilar dissection Infection Meningitis Encephalitis Polyneuritis Posterior fossa tumors Intoxications Alcohol Antiepileptics Benzodiazepines Cyclic antidepressants Sedative-hypnotics Inhalants Carbon monoxide Lead Intermittent/episodic Migraine and migraine variants Seizures Multiple sclerosis Metabolic/inborn errors Urea cycle defects Amino acid disorders Organic acid disorders Recurrent genetic ataxias Chronic/progressive Tumor Abscess Genetics (inborn errors or metabolism, storage diseases, spinocerebellar ataxias) Hydrocephalus Cerebellar malformations: agenesis, hypoplasia, Chiari malformations, and Dandy-Walker cysts |
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