Paediatrics: Acute encephalopathy

Acute encephalopathy

Encephalopathy is defined as a degeneration of brain function, due to different causes. However, in practical terms it is thought to denote a process with impaired cognition, ± focal neurological signs. It normally is matched by a typical EEG trace: with an abundance of slow waves. There is reduced consciousness as assessed by the GCS.

Note: The difference between encephalopathy and encephalitis—the latter being encephalopathy s to an infective process—mainly viral. It is thought that CSF with normal WCC excludes encephalitis.

Assessment

The cause will be apparent within the history in the majority of cases, e.g.

meningitis, trauma, or HIE. Consider/ask about potential causes:

·  Infections: viruses as well as bacterial, e.g. meningitis.

·  Metabolic: including mitochondrial dysfunction, check for consanguinity.

·  Autoimmune: e.g. ADEM, thyroiditis.

·  Increased ICP: e.g. tumours obstructing CSF.

·  Lack of oxygen or blood flow: hypoxia-ischaemia.

·  Trauma.

·  Toxins (inc. solvents, drugs, alcohol, and metals).

·  Radiation.

·  Nutrition.

If not, or to confirm then perform a full neurological examination—with particular reference to assessment of the conscious state and place on the GCS, eye movement, fundi, bulbar control (can the child manage secre-tions?), upper motor neuron signs in limbs. Also check for other system involvement—skin, immune, and viscerae.

Management

These children are very sick, and at risk of cardiorespiratory compromise, until a diagnosis has been made, and they have a secure plan to manage the encephalopathy. Management should be performed simultaneously to investigation.

Is the GCS<8? If so proceed to intubation/ventilation, keep the CO₂ be-tween 4 and 5kpa.

·Treat shock if present. If not, then IV fluids at 60% of normal daily volume requirements. Early consideration for NG feeding, if too unwell too feed orally.

·Unless there is a conformed non-infective diagnosis, treat as if meningitis. Also treat with acyclovir for Herpes, and oral clarithromycin for mycoplasma pneumoniae.

·Check, full blood count, CRP, ESR, glucose and renal/liver function. If cause unclear, check serum ammonia, lactate, acylcarnitine profile, urine organic acid profile and store for further assessment as needed, e.g. toxicology.

·Only when stable, perform LP make sure there is a full WCC, glucose, protein, lactate and stored sample for subsequent viral analysis/ immunology as needed.

·Neuroimaging is essential, but should only be performed once the child is stable. Always give enhancement, if possible scan the spine as well, and get MRI rather than CT, although the latter is better than nothing.

Further therapy will depend on the case, and should only happen within a centre with a paediatric neurology service and the intensive care unit.