Investigating Stroke and related conditions

• CT Brain, with contrast is around 85% sensitive for a diagnosis of CVST. If there is doubt MR Venography should be undertaken
• Negative CT in the context of persistent neurological impairment should prompt further investigation with MRI or, if this proves impossible, repeat CT, as pathologies such as arterial ischaemic stroke become more apparent on CT with time.
• In Arterial ischaemic stroke (AIS) as well as brain imaging, investigation should include evaluation for thrombophilia (including anticardiolipin antibodies). The history should include enquiry about previous thrombosis or fetal loss, and consideration should be given to referring the mother for haematological evaluation, especially if she intends to have further pregnancies.
•  MRI (including diffusion-weighted imaging and MR angiography of the cerebral circulation from the aortic arch to the circle of Willis.
• The presence and morphology of arterial disease is one of the most important determinants of subsequent treatment (for example, anticoagulation for dissection, aspirin for focal cerebral arteriopathy, revascularization for moyamoya).
• The other important determinants of acute Management are identification of sickle cell disease (though AIS rarely presents in this way) and the presence of cardiac disease (which might lead to anticoagulation).

Other than vascular imaging and echocardiography the following investigations could he considered:

• full blood count and ferritin (to detect anaemia)
• haemoglobin electrophoresis in Black and South Asian children
• thrombophilia evaluation (protein C, S, antithrombin, factor V Leiden, t-MTHIR PT20210, lupus anticoagulant and anticardiolipin antibodies)
• total plasma homocysteine (significant if > 13.5μmol/L)
• random cholesterol and triglycerides
• transferrin isoforms
• serology: mycoplasma, borellia, varicella zoster.
• AIS in the distribution of the posterior circulation (mostly seen in boys) requires exclusion of vertebral artery dissection, which may necessitate catheter cerebral angiography and screening for Fabry disease (measure plasma alpha-galactosidase A).
• Recurrence of AIS should always prompt reviewing the diagnosis, specifically to exclude a non-vascular cause, and evaluation for potentially treatable conditions such as cerebral vasculitis or moyamoya.
• In CVST Thrombophilia is much more prevalent than in children with AIS and should be sought as it may guide duration of therapy and future management.

Non-traumatic intracranial haemorrhage

• a structural malformation of the cerebral vasculature (most commonly arteriovenous malformations) should be excluded
• Aneurysms are much less common in children, even those presenting with subarachnoid haemorrhage, but may be familial (if there are more than two affected first-degree relatives), associated with polycystic kidney disease or with infection
• Bleeding diatheses should always be excluded, especially in newborn infants, in whom haemorrhagic disease or haemophilia may present in this way.
• It is always important to consider inflicted head trauma, which is usually associated with subdural haemorrhage.
• In the acute stage the priority is to identify any underlying structural malformation; unless urgent haematoma evacuation is clinically indicated (in which case catheter angiography should be undertaken)
• CT angiography is currently the initial investigation of choice
• MRI should be undertaken if CT angiography is negative as, rarely, pathologies not apparent on CT may be identified (for example, brain tumour with secondary haemorrhage)
• It is generally advisable to defer catheter angiography to a time at which the acute haematoma will have resolved and when the diagnostic examination might be combined with endovascular intervention.

'Stroke-like' episodes

• space-occupying lesion (tumour) (brain MRI)
• encephalitis (brain MRI, CSF, microbiology)
• acure disseminated encephalomyelitis (ADEM) (brain MRI)
• mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) (lactate, mtDNA analysis)
• epilepsia partialis continua (EEG, POl.Gl, etc.)
• ornithine transcarbamylase and such-like (ammonia, urine orotic acid and uracil)
• Hashimoto encephalopathy (thyroid peroxidase antibody)
• hypoglycaemia (blood glucose, and - if not insulin induced - urinary organic acids and acylcarnitines)
• congenital defect of glycosylation (CDG) (serum sialotransferrins, EEG during episode: shows spike and wave)
• elF2B-related (brain MRI +CSE asialotransferrin).
• stroke-like episodes may be associated with hemispheric non-convulsive status epilepticus only detectable by ictal EEG. This is a feature of the stroke-like episodes in CDG type 1a and is likely to be a feature of mitochondrial disorders such as with POLG1 mutations.

Source:
Mary D. King, 2009. A Handbook of Neurological Investigations in Children. 1 Edition. Mac Keith Press.