Healthcare and Medicine Reference
In-Depth Information
CHAPTER 7
Sampling: Lumbar Puncture
Mike Byrne
Birmingham Heartlands Hospital, Birmingham, UK
Box 7.1 Lumbar puncture and anticoagulation
OVERVIEW
By the end of this chapter you should have a good understanding of:
indications and contraindications of lumbar puncture (LP)
Patient on full anticoagulation:
warfarin - stop and ensure INR <1.5
anatomical considerations
unfractionated heparin infusion - stop infusion and ensure APTT
different types of spinal needles
normal (after approx 4 h)
the practical procedure of LP
Prophylactic anticoagulation:
unfractionated heparin - wait 4 h after dose, can give heparin 1 h
possible complications and their management
interpretation of results for meningitis.
after LP
low molecular weight heparin - wait 12 hours after dose, can
give 4 hours after LP
Platelets - ensure >80 × 10 3
Aspirin/NSAIDs - no increased risk of spinal/epidural haematoma
Introduction
Lumbar puncture (LP) is an infrequently performed procedure
that has an important role in the diagnosis and treatment of
many serious conditions. A full understanding of the anatomy
and contraindications is essential if potentially life-threatening
complications are to be avoided.
Contraindications
These can be absolute or relative.
Absolute
Patient refusal.
Indications
You are most likely to encounter lumbar puncture on the acute
medical wards for the diagnosis of meningitis or subarachnoid hae-
morrhage. Its indications are:
Clotting abnormality or full therapeutic anticoagulation. Risk of
epidural haematoma causing cord compression (see Box 7.1 for
timing of LP if anticoagulation has been given).
Raised intracranial pressure (ICP) (risk of 'coning'). If raised ICP
is suspected (see Box 7.2 for symptoms and signs) then a CT scan
should be performed before LP to look for hydrocephalus or a
space-occupying lesion. Unfortunately a CT scan is not infallible
so the indication for LP should be strong.
Local infection at injection site. Risks causing epidural abscess or
Diagnostic
CNS infection (e.g. bacterial, viral, TB meningitis)
subarachnoid haemorrhage
neurological disease (e.g. multiple sclerosis, Guillain-Barré
syndrome).
meningitis.
Therapeutic
intrathecal chemotherapy
Relative
Systemic sepsis. Risks causing epidural abscess or meningitis.
removal of CSF (e.g. idiopathic intracranial hypertension).
Neurological disease. Any subsequent new neurological symp-
toms can be blamed on the LP. The indication needs to be strong,
the patient's informed consent given and a full neurological
examination should be performed and documented before LP.
Anaesthetic
spinal anaesthesia for lower limb/lower abdominal surgery.
Anatomy
Lumbar puncture requires the insertion of a needle into the
cerebrospinal fl uid (CSF) in the lumbar region of the spine
(Figure 7.1). In adults the spinal cord ends at the lower border of
 
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