Paediatrics: Acute abnormal movements

Acute abnormal movements

Ataxia

An abnormality in gait that is wide-based, staggering, and unsteady may have a number of causes including:

·  Posterior fossa tumours.

·  Inborn errors of metabolism.

·  Poisoning.

·  Brainstem encephalitis.

·  Post-infectious or autoimmune: acute cerebellar ataxia.

·  Trauma.

·  Vascular disorders.

·  Congenital malformations: Dandy–Walker.

·  Neurological: olivopontocerebellar degeneration, ataxia–telangiectasia (at), adrenoleucodystrophy, Friedreich’s ataxia (FrA).

·  Conversion disorders.

Clinical review

·  Speech: increased separation of syllables and varied volume—scanning speech.

·  Neurology: sensory disturbance in proprioception, positive Romberg, nystagmus with eye movement.

·  Systemic: immunodeficiency in AT; hypertrophic cardiomyopathy and diabetes in Fanconi’s anaemia (FA).

Investigation

Cerebral imaging, if cause not found plasma and CSF analysis for the above, with particular reference to assessing for varicella, streptococcal and other infections, and for inborn errors of metabolism, e.g. urea cycle disorders.

Chorea

Jerk-like movements may involve the face, arms, or legs. In childhood the causes include:

·  Drugs: anticonvulsants, psychotropics, benzodiazepine withdrawal after intensive care.

·  Systemic illness: Sydenham’s chorea, SLE, hyperthyroidism.

·  Genetic: Huntington’s chorea, glutaric aciduria and other inborn errors of metabolism, benign familial chorea.

·  Other: pregnancy.

Streptococcal infection

Sydenham’s chorea is often associated with streptococcal infection. It occurs in older children particularly girls. It is frequently misdiagnosed as being psychogenic, particularly as it may be associated with emotional liability. It is characterized by the onset of a mild to moderate chorea (may be unilateral) that is more distal, in a well child (possibly with recent infection).

·  About 20% of rheumatic fever cases include chorea.

Treatment: high-dose penicillin V 500mg, oral, bd., for 10 days; then daily prophylaxis.

·Sodium valproate is the first line treatment, if inborn errors of metabolism are unlikely, as it can cause metabolic decompensation.

·Benzodiazepines, phenothiazine, haloperidol may control the movement.

·Improvement may occur over weeks to months.

Paediatric autoimmune neuropsychiatric disorder associated with streptococcus (PANDAS)

PANDAS has specific diagnostic criteria and is accompanied by behav-ioural problems, e.g. obsessive–compulsive disease and tics. There is some debate as to whether it represents a separate entity.

Conversion or ‘psychologically mediated’ disorders

A high percentage of children older than 7yrs who present with rapidly progressing and bizarre neurological symptoms, with no sign of system-ic illness, and retained consciousness have a conversion disorder. These children are more likely to be teenage girls. However, it is important that this fact should not prejudice your clinical assessment—major oversights and mistakes can be made. These children tend to be well and have signs that cannot be explained anatomically, e.g. paralysis of one leg and the contralateral arm, sensory disturbances that do not fit a typical neuropa-thy, and visual phenomena.

The initial diagnosis should be that of a genuine physical disorder until all assessments (medical, psychological, and social) are complete.

Examination must be thorough. You may reveal inconsistent signs such as an inability to lift the leg off bed, but the child is able to walk across the room. Video can be very helpful, especially if a second opinion is needed/the signs intermittent.

Investigation

These should only be undertaken if clinically indicated, as there is a risk of a false positive

Imaging 

Sophisticated imaging is at the physician’s discretion, but the fam-ily is likely to become very distressed if a psychological diagnosis is given while there are outstanding investigations. Therefore correlate all the rel-evant information, decide if it is either psychological or a physical disorder. If unsure refer for expert opinion.

Treatment 

If confident it is psychological follow the strategy for PDPE.