Investigations

1st investigations to order

glucose

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Result
Test

Take emergency bloods for glucose.[19] Abnormal levels of glucose can cause seizures and status epilepticus.

Result

may be normal; may show hypoglycaemia or hyperglycaemia

arterial blood gases

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Result
Test

Take emergency bloods for arterial blood gases.[16] Significant metabolic abnormalities are common following prolonged seizures. These usually normalise following seizure termination.

Result

may show normal values; may show abnormal values in the presence of acidosis or alkalosis

urea

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Result
Test

Take emergency bloods for urea levels.[19] Raised levels may provoke acute symptomatic seizures.[19]

Result

may be normal; may be raised

creatinine

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Result
Test

Take emergency bloods for renal function tests. This is to establish a baseline, investigate the cause of seizures, and identify those who might be at particularly high risk of complications such as acute kidney injury (from rhabdomyolysis).[19] See Acute kidney injury.

Elevated creatinine may provoke acute symptomatic seizures.[28]

Result

may be normal; may be raised

liver function tests

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Result
Test

Take emergency bloods for liver function tests.[16][19]

Abnormal levels may indicate systemic disease or alcohol-use disorder.[19]

Result

may be normal; may be abnormal in the presence of systemic disease or alcohol-use disorder

sodium, calcium, and magnesium

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Result
Test

Take emergency bloods for sodium.[16][19] Also take emergency bloods for calcium and magnesium levels.[16][19] Electrolyte imbalances can cause status epilepticus.[19]

Result

may show normal values; may show hyponatraemia, hypocalcaemia, hypomagnesaemia

full blood count

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Result
Test

Take emergency bloods for full blood count.[16][19]

Abnormal levels may indicate infection (raised WBC count or chronic alcohol-use disorder (raised mean corpuscular volume).[19][29]

Result

may be normal; may show raised WBC count or raised mean corpuscular volume

C-reactive protein

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Result
Test

Take emergency bloods for C-reactive protein levels.[16][19]

Result

may be normal; may be raised if there is infection or systemic inflammation

clotting screen

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Result
Test

Take emergency bloods for a clotting screen.[19]

Take as a baseline measure and to identify patients with coagulopathy.[19]

Result

usually normal; may be abnormal in people with coagulopathy

anticonvulsant drug levels

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Result
Test

Take emergency bloods for anticonvulsant drug levels (irrespective of a known history of epilepsy).[19]

A sub-therapeutic anticonvulsant level is a common cause of status epilepticus in people with epilepsy. This is usually due to poor adherence to treatment.[9] Remember that people with epilepsy may have an acute cause for their status epilepticus.[11]

Result

may be normal; may show sub-therapeutic levels

chest x-ray

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Result
Test

Arrange an emergency chest x-ray to evaluate the possibility of aspiration.[1] See Aspiration pneumonia.

Result

may be normal; may show aspiration pneumonia

Investigations to consider

ECG

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Result
Test

Arrhythmias or cardiac ischaemia may be the result of prolonged status epilepticus (and, in rare cases, its cause). Early treatment of these potential complications is of high priority. Widened QRS complex may suggest overdose of prescribed anti-epilepsy medications including carbamazepine.[10]

Result

may show abnormal heart rhythm or evidence of cardiac ischaemia

CT-head

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Result
Test

Consider an urgent CT-head in people with no previous epilepsy history or with new focal neurology, head injury, or for any patient with refractory status epilepticus.[16]

Result

may be normal; may show haemorrhage, evidence of ischaemic strokes, oedema, tumour, hydrocephalus

lumbar puncture

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Result
Test

Consider a lumbar puncture for cerebrospinal fluid evaluation if you suspect central nervous system infection or inflammation.[1]

Result

may show high WBC count, high protein, and low glucose in the presence of infection

toxicology screen

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Result
Test

Consider a toxicology screen (blood and urine samples) if you suspect substance misuse/overdose.[1][19]

  • Serum alcohol level: detectable levels indicate recent alcohol ingestion.[19]

  • Urinary drug screen: detectable levels may indicate recreational drug use (e.g., cocaine, amphetamines).[19]

Practical tip

Save 5 mL of serum and 50 mL urine for future analysis, e.g., toxicology.

Result

may be positive for alcohol or potentially epileptogenic substance

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