Ataxia is a term derived from Greek referring to impairment and lack of ability to coordinate or perform voluntary movements.1 Ataxia can present and be noted in children of all age groups ranging from young infants to adolescents. Both genders, plus all racial and ethnic groups, may be affected. However, since there are many conditions and disorders that may cause ataxia in children, there is great variability in its underlying pathogenesis, risk factors, and presentation.

The cerebellum is the structure that, its dysfunction, is commonly attributed to the presentation of ataxia. On the other hand, disturbance to the structures or function of other sites such as the peripheral nerves, dorsal columns of the spinal cord, brainstem, or frontal cerebral cortex, which provide connections or pathways into and out of the cerebellum, may also play contributing roles in ataxia.2,3

Most children presenting with ataxia typically present with abnormal gait.2 Some parents usually describe their children as clumsy, with poor coordination and balance, and unable to perform motor tasks smoothly4,5; whereas some are reported to walk as if under the influence of alcohol.6 The gait is usually wide-based and staggering, with elevation of the feet and then slapping the soles on the ground.2 The impaired balance and coordination may be worsened by closing both eyes (Romberg sign). Dysfunctions in the sensory and proprioceptive cerebellar inputs from the peripheral nerves and the posterior spinal columns may result in children looking at their feet during ambulation.2,3 Frequent falls and fears of injury may urge parents to seek advice from health care professionals. Lesions affecting the cerebellar vermis may lead into ataxia affecting the trunk with difficulties in maintaining axial posture and balance in an upright position. In addition, titubation (bobbing of the head forward and backward)4 may be noted with vermal lesions. The lesions affecting the cerebellar hemispheres may lead into hypotonia and ataxia affecting the limbs ipsilaterally.4

Associated findings in children presenting with ataxia may also include impaired speech, ocular movements, fine motor skills, and intentional tremors.4 The speech may be described as slow, scanning, with uneven volume and separation of syllables.2,4 Nystagmus and ocular dysmetria, overshooting and an inability to keep the moving eyes towards a targeted point, may be noted.1,6 The smooth and accurate performance of rapid alternating movements (diadochokinesia) and complex motor activities may be impaired.4Tables 7-1 summarizes some of the common and rare presentations of signs and symptoms of ataxia in children.

Obtaining an adequate history is the most essential part of evaluating children who present with ataxia. Some of the key elements in the history that can help with identifying the underlying causes include the child’s age plus the course and pattern of onset at the time of presentation (acute versus chronic, intermittent, or progressive). Presence of fever, cough, congestion, rhinorrhea, rash, vomiting, or diarrhea at the time of or within few weeks prior to presentation may identify an infectious or postinfectious source. Other features such as confusion, stiff neck, and seizures may be worrisome for more serious etiologies including meningitis, meningoencephalitis, or acute disseminating encephalomyelitis (ADEM). Experiencing head and neck trauma plus exposure to drugs and toxins should be determined. Headaches, emesis, and focal neurological findings are of concern for acute complications of mass lesions (tumors, abscess, arteriovenous malformations), strokes, or hemorrhage in the regions of the brainstem, cerebellum, or the posterior fossa. Intermittent and recurrent ataxia may be suggestive of migraines, epileptic seizures, postictal period, or disorders of inborn error of metabolism. Chronic or progressive ataxia may be caused by slowly developing tumors or congenital structural malformations, genetic, inherited disorders.

Additional information that may be beneficial in evaluating and diagnosing a child with ataxia include the presence of other medical or systemic illnesses, adequate assessment of the developmental milestones, plus the detailed family and social histories.

After gathering and obtaining a detailed history, a comprehensive general and neurological examination should be performed. The neurological examination should start with the evaluation of the child’s mental status. The examiner should assess the alertness, social interaction, eye contact, and response to verbal and tactile stimuli. In older children, the speech, spelling, naming of objects, calculation, attention, recent or remote memory, and general fund of knowledge should be determined.

A detailed examination of the cranial nerve function and integrity with assessment of the vision, pupillary response to light and accommodation, extraocular movements, nystagmus, facial muscles strength and sensation, hearing, chewing, swallowing, gag reflex, neck and tongue sensation, plus movement should be emphasized. A fundoscopic examination of the eyes should be performed to evaluate for papilledema.

The strength, sensation for light touch, pin prick, temperature, vibration, proprioception, muscle tone, and deep tendon reflexes can also be helpful in localizing other lesions within the nervous system that may be attributed to ataxia.

The cerebellar exam may reveal intentional tremor, dysmetria, abnormal diadochokinesia, and heel to shin or a positive Romberg sign. The gait exam focusing on heel, toe, and tandem walking are also essential in evaluating children with ataxia.

Acute presentation of ataxia may be caused by a variety of conditions including infections, postinfections, trauma, toxins, inflammatory, tumors, strokes, hemorrhage, and seizures (Table 7-2).2,3,5 Among the infectious agents, viruses including varicella, Epstein–Barr virus, echovirus, coxsackievirus, measles, mumps, HIV, rubella, and polio are commonly associated with ataxia.2,3,5 Bacterial agents such as Streptococcus pneumoniae, Haemophilus influenzae, Listeria monocytogenes, and Escherichia coli are common pathogens.2,3,5 Syphilis, Lyme disease, tuberculosis, and mycoplasma pneumoniae have also been associated with ataxia in children. Toxoplasmosis and cysticercosis are two parasitic agents commonly attributed to ataxia,3 especially among individuals exposed to cat feces and the immigrant population from Latin America and Asia, respectively. Postinfectious conditions such as ADEM and inflammatory disorders such as multiple sclerosis can also lead to acute ataxia.