ORGANUM
Ataxia is the inability to make accurate, smooth, and coordinated movements, usually due to a dysfunction of the cerebellar pathways. If either the afferent (proprioception) or efferent cereballar connections (cerebellum through thalamus to cerebral cortex) are disturbed, the patient has ataxia.
Truncal ataxia reflects disturbances of the midline cerebellar vermis - medulloblastoma, acute post infectious cerebellar ataxia, or ethanol intoxication). Appendicular ataxia reflects disturbances of the ipsilateral cerebellar hemisphere (cystic cerebellar astrocytoma).
The most common causes of acute ataxia in childhood are post infectious acute cerebellar ataxia and drug intoxications. Discrete lesions within the posterior fossa, tumours (medulloblastoma, ependymoma, cerebellar astrocytomas), MS, strokes, and hemorrhages may cause ataxia. Other causes include benign paroxysmal vertigo, head trauma, seizures, postictal states, migraine, paraneoplastic opsoclonus-myoclonus syndrome associated with neuroblastoma, and inborn errors of metabolism. Congenital disorders also may produce chronic, non progressive ataxia. There are a number of inherited ataxia syndromes.
Drug intoxication is the most common cause of acute ataxia among children. Overdose with any sedative-hypnotic agent can produce acute ataxia and lethargy, but ataxia without lethargy usually results from intoxication with ethanol or anticonvulsant drugs. It is important to ask about any medications or abuse the patient may have access to. Treatment is supportive
This may occur 1 to 3 weeks following varicella, infectious mononucleosis, mild respiratory or gastrointestinal viral illnesses, or other infections. The pathogenesis is uncertain and may represent either a direct viral infection of the cerebellum, or more likely an autoimmune response precipitated by the viral infection and directed at the cerebellar white matter. Symptoms begin abruptly, causing truncal ataxia, staggering, and frequent falling. Dysmetria of the arma, dysarthria, nystagmus, vomiting, irritability, and lethargy may be present. Symptoms, which may be severe enough to prevent standing or sitting, usually peak within 2 days, then stabilize and resolve over several weeks. CSF examination shows mild lymphocytic pleocytosis or mild elevation of protein content. Brain MRI may reveal cerebellar enhancement. Care is supportive and no specific therapy is available except to prevent injury during the ataxic phase.
Brain tumors are the second most common neoplasm in children - 50% arise from within the posterior fossa. Tumours that arise in the posterior fossa or brainstem produce progressive ataxia with headache that may be acute or gradual in onset. There is progressive ataxia with headache that may be acute or gradual in onset. There is progressive worsening over days, weeks, or months, typically with signs and symptoms of elevated intracranial pressure. The ataxia and dysmetria may result from primary cerebellar invasion or from obstruction of the CSF pathways at the aqueduct of Sylvius or fourth ventricle with resultant hydrocephalus. The most common tumours in this region include medulloblastoma, ependymoma, cerebellar astrocytoma, and brainstem glioma.
Rarely, a neuroblastoma located in the adrenal medulla or anywhere along the paraspinal sympathetic chain in the thorax or abdomen is associated with degeneration of Purkinje cells, and thus the development of severe ataxia, dysmetria, irritability, myoclonus and opsoclonus. An immunologic reaction directed toward the tumour may be directed towards the Purkinje cells and other neuronal elements. The myoclonic movements are irregular, lightning-like movements of a limb or the head. Opsoclonus is a rapid, multidirectional, conjugate movement of the eyes, which suddenly dart in random directions. The presence of opsoclonus-myoclonus in a child should prompt a vigorous search for an occult neuroblastoma.
Several rarer inborn errors of metabolism can present with intermittent episodes of ataxia and somnolence. These include Hartnup disorder, maple syrup urine disease, mitochondrial disorders, abetalipoproteinemia, and vitamin E deficiency.
Ataxia is a potential manifesation of acute labrynthitis, but the vertigo, nausea and vomiting, and associated signs of pallor, sweating and nystagmus is seen. Cerebellar function should remain intact.
Ataxia-telangiectasia is an autosomal recessive genetic disorder. It is the most common of the degenerative ataxia. Affected patients present with ataxia around 2 years old, progressing to loss of movement by adolescence. In mid-childhood, telangiectasia is evident over the sclerae, nose, ears, and extremities. Abnormalities in immune function and greatly increased risk of lymphoreticular tumours result in early death.
Progressive, autosomal recessive disorder. Children present in the later primary school years with ataxia, dysmetria, dysarthria, decreased proprioception and vibration, absent deep tendon reflexes and nystagmus. Many develop hypertrophic cardiomyopathy and skeletal abnormalities (high-arched feet, hammer toes, kyphoscoliosis