Approach to the child with acute ataxia Dr Mohamed Abu nada Pediatric Neurology Department

1. Approach to the child with acute ataxia Dr Mohamed Abunada Pediatric Neurology Department Specialized children Hospitalمستشفي الأطفال التخصصي

2. Ataxia : • a disturbance of smooth, accurate • coordination of movements. • most common manifestation is an • unsteady gait. • usually a result of cerebellar dysfunction. • However, disturbances at many levels • of the CNS can affect coordination

3. Acute ataxia • uncommon presenting complaint in children. • causes of acute ataxia include life-threatening conditions • mass lesions • central nervous system (CNS) infection. • the majority of children have a benign, self-limited process.

4. CAUSES • Life-threatening conditions • Tumors • Intracranial hemorrhage • Stroke • Infection:Cerebellar abscesses, Brainstem encephalitis • ADEM

5. *Common conditions • Acute cerebellar ataxia  • Guillain-Barré syndrome • Miller-Fisher syndrome • Labyrinthitis • Toxic exposure •   Migraine syndromes • Trauma    

6. Other conditions—that can cause acute and chronic ataxia • Hypoglycemia . • Seizure disorder. • Conversion disorder. • Tick paralysis. • Inborn errors of metabolism: urea cycle disorders, • amino acidopathies, • mitochondrial disorders, • organic acidopathies. • Congenital anomalies:Congenital anomalies of the posterior fossa • (Dandy-Walker syndrome, Chiari malformation) • Degenerative/genetic conditions :ataxia-telangiectasia • neuronal ceroid lipofuscinosis , Niemann-Pick disease , • Friedreich ataxia , Vitamin E deficiency, multiple sclerosis

7. EVALUATION • History: • *refusal to walk or with a wide-based, "drunken" gait. • *Onset of symptoms • A rapid onset: • indicative of a traumatic, infectious, post-infectious toxic etiology. • -A slower, more progressive onset usually over a few days : • Guillain-Barré syndrome (GBS) and metabolic syndromes • A slower and insidious course: • brainstem and cerebellar tumors, medulloblastomas may grow • rapidly.

8. *Associated symptoms - Otalgia, vertigo, and vomiting suggest acute labyrinthitis. - Recurrent night-time or early-morning headaches with or without vomiting suggest ICP that develop with brain tumor. - Access to medications (phenytoin, carbamazepine, phenobarbital, primidone, antihistamine, benzodiazepins, others drugs), and other toxic substances (lead, ethanol) should be determined. - A history of antecedent head trauma is consistent with an intracranial injury, - Patients with a recent infection or vaccination may have a post-infectious demyelinating process( acute cerebellar ataxia, GBS, or acute post-infectious demyelinating encephalomyelitis (ADEM). - Previous similar episodes of acute ataxia suggest a migraine syndrome, seizure, or inborn error of metabolism.

9. General examination : • Bradycardia, abnormal respiratory pattern, HTN _ ICP. • Bulging anterior fontanel may indicate ICP. • An ipsilateral head tilt _ with posterior fossa tumors. • Papilledema indicates ICP as may occur in • posterior fossa tumors • that obstruct spinal fluid flow leading to hydrocephalus.

10. Fever is consistent with an infectious process. • . Meningismus , fever and a toxic appearance is • concerning for a CNS infection. • Nystagmus can develop with vestibular, cerebellar, • or brainstem disorders. Opsoclonus may be associated • with an occult neuroblastoma. • . Otitis media , hearing loss, vomiting and intense vertigo indicate acute labyrinthitis. • . A healing rash or viral exanthem _ a clue for • acute post-infectious cerebellar ataxia.

11. Neurologic examination : • Mental status : • Abnormal mental status suggests ingestion, ADEM, • meningitis, encephalitis, or stroke. • Lethargy may be present in many inborn errors of metabolism. • In comparison, children with post-infectious cerebellar ataxia • are normally alert and interactive. • Cranial nerves : • Abnormalities of cranial nerve function suggest post. fossa • lesions, brainstem encephalitis, or the Miller Fisher syndrome.

12. Motor examination : **Acute onset of weakness may stagger as an attempt to compensate. This gait abnormality may be mistaken for true ataxia and has been called "paretic" ataxia. Paretic ataxia is proportional to the degree of weakness. It may be due to GBS, botulism, myasthenia gravis, transverse myelitis, or tick paralysis. ** (DTR) Deep tendon reflexes absent in patients with GBS, botulism, and tick paralysis.

13. Cerebellar examination : • Gait wide-based, unsteady, lurching, or staggering. • Speech abnormalities include • fluctuations in clarity, rhythm, tone, volume. • Patients may have difficulty maintaining truncal position • (titubation). • Coordination of voluntary movement, as demonstrated with • over- or under-shooting (best seen on finger-nose testing) • rapid alternating movements (dysdiadochokinesia), is poor. • Hypotonia and tremor may also occur.

14. Findings that localize the disorder within the cerebellum include the following:       - Vermal (midline cerebellar) lesions cause dysarthria, truncal titubation and gait abnormalities.       - Lesions of the cerebellar hemispheres result in ipsilateral limb dysmetria, hypotonia, and tremor. Children may veer in the direction of the affected cerebellar hemisphere when walking.

15. Laboratory • Toxicologic screen : • urine screen for drugs or blood for specific drug levels. • Blood glucose: • A bedside test - hypoglycemia. • Metabolic evaluation: • liver function tests, blood pH, CBC, amino acid in blood • and urine, serum lactate, pyruvate , ammonia levels, urine organic acids. • CSF examination : • CNS infection, such as meningitis or encephalitis. • Moderate CSF protein elevation can occur in acute cerebellar ataxia, • ADEM, MS. • CSF protein usually elevated in GBS, but it may be normal in as many • as 20 percent of children within a week of symptom onset.

16. Neuroimaging • before a LP is performed when there is concern for ICP. • Imaging may also be helpful when considering a diagnosis of exclusion, such as acute cerebellar ataxia or a conversion disorder. • Neuroimaging should be obtained for patients with acute ataxia who have • altered levels of consciousness, • focal neurologic signs, • cranial neuropathies, • marked asymmetry of ataxia, • concern for a mass lesion, • or a history of trauma.

17. Magnetic resonance imaging (MRI) • is superior to computed tomography (CT) for detection . posterior fossa lesions (tumors, strokes, abscess). • demyelinating diseases • or brainstem encephalitis. • Computer Tomography (CT) • is generally more available emergently than MRI. • CT can usually detect conditions that require immediate surgical intervention such as .hydrocephalus, • traumatic injury, • and many mass lesions.