LUMBAR PUNCTURE

Dr Abdulaziz Alrabiah, MD

• Indications: diagnostic if suspect meningitis -encephalitis

• Meningitis culture of CSF

• Encephalitis viral or bacterial

• subarachnoid haemorrhage blood in CSF

• Guillain Barré syndrome measure protein in CSF

• multiple sclerosis

• benign intracranial hypertension

• febrile seizures

• children with fever without focus

Contraindications:

• local sepsis
  SKin infection
• Bleeding tendency
  • systemic anti-coagulation
  • bleeding diathesis
  • thrombocytopenia with platelet counts $<50\times 10^9/L$

* Elevated ICP or suspicion of mass lesion z

✓ Papilloedema

✓ focal neurological deficit

✓ abnormal conscious state

if you suspect pt has high ICP
do CT or MRI before LP
to avoid Herniation

Complications:

• uncal / tentorial herniation i.e. if raised intracranial pressure
• post LP headache
• spinal / epidural haematoma
• infection i.e. meningitis
• worsening paraparesis
• laceration of annulus fibrosis or nucleus pulposus
• nerve root puncture or graze

Method of insertion

• between L4-L5

• midway

• between both Iliac crests

• direct needle toward umbilical

• bead facing up to avoid injury of structure

CSF analysis

	Normal	Bacterial	Viral	Fungal/TB
Pressure (cmH2O)	5-20	> 30	Normal or mildly increased
Appearance	Normal	Turbid	Clear	Fibrin web
Protein (g/L)	0.18-0.45	> 1	< 1	0.1-0.5
Glucose (mmol/L)	2.5-3.5	<2.2	Normal	1.6-2.5
Gram stain	Normal	60-90% Positive	Normal
Glucose - CSF:Serum Ratio	0.6	< 0.4	> 0.6	< 0.4
WCC	< 3	> 500	< 1000	100-500
Other		90% PMN	Monocytes 10% have >90% PMN 30% have >50% PMN	Monocytes