Encefalopatía neonatal
24 - Junio - 2017
Table 1 Early investigations to assess neonatal encephalopathy
First line investigations
Comment
Full blood count
May suggest infection, haemorrhage, thrombocytopenia.
Clotting
Clotting disorders may be seen in HIE and sepsis, but should also lead the clinician to think about anaemia secondary to inherited coagulation disorders and intracranial haemorrhage.
Direct Coombs test
Evidence of haemolysis.
Liver function test
May be abnormal in HIE but is usually transient unless a severe insult to the liver has occurred. Abnormal liver function tests can be a feature of bilirubin encephalopathy, metabolic conditions, congenital infections, and acute sepsis with bacteria and viruses, including herpes simplex virus.
Urea and electrolytes
May be impaired if the kidneys have had an ischaemic insult but usually improves, unless severe ischaemic injury has occurred. May also be impaired in congenital abnormalities of the kidneys, metabolic conditions.
Whole blood glucose (rather than serum glucose as the latter is around 15% higher than whole blood)
Hypoglycaemia may be seen following HIE, but is usually correctable with appropriate treatment. Persistently low glucose requires further evaluation.
Blood lactate
Lactate is often measured on the blood gas, and may increase rapidly to high levels following HIE, but usually falls within days and returns to normal. A persistently high lactate should trigger further investigations.
Neurophysiology
Amplitude integrated EEG (aEEG) using a cerebral function monitor and/or serial standard EEGs to identify seizures and monitor recovery of encephalopathy. Will also help diagnose neonatal epilepsy syndromes.
Second line investigations to consider ordering which are available quickly (if concerned this is not typical HIE)
Urinary ketones
Urinary ketones, when present, in a neonate indicate the use of intermediary pathways of metabolism and are almost pathognomonic of the presence of a metabolic disorder.
Ammonia
In very sick neonates, ammonia, up to about 110 μmol/L may be present. Very high levels (>200 μmol/L) usually indicate a metabolic cause, for example, urea cycle defect and warrants further investigations.