Investigations

Once IV/IO access is established, blood should be taken for blood cultures and meningococcal PCR to aid in reaching a definitive laboratory diagnosis. Other laboratory tests which may assist in directing management and predicting prognosis include:

• Blood glucose
• Full blood count (FBC)
• Coagulation (PT/INR)
• Urea & electrolytes (U&E)
• C-reactive protein (CRP)
• Venous or capillary blood gas (pH, base excess, bicarbonate, lactate)

Lumbar puncture[4]

Lumbar puncture should be performed as a primary investigation unless contraindicated. It should not delay the administration of antibiotics. CSF examination should include

• White blood cell count and examination
• Total protein
• Glucose
• Gram stain
• Microscopy and culture
• Bacterial PCR testing (performed if culture negative)

Contraindications to lumbar puncture include

• Signs of raised intracranial pressure (such as reduced or fluctuating consciousness, focal neurology, abnormal posture, relative bradycardia and hypertension)
• Shock
• Extensive or spreading purpura
• Convulsions
• Coagulation abnormalities

In an unwell child, where there is high clinical suspicion of invasive meningococcal disease, performing investigations such as blood tests or a lumbar puncture should not delay resuscitation and definitive treatment[4].