Lumbar puncture Flashcards
List 3 indications for lumbar puncture
Suspected CSF/CNS infection, Check CSF composition and colour, diagnose guillain-barree (high protein content) and MS (oligoclonal bands)
List 7 contraindications to lumbar puncture
Patient refusal, Intracranial bleed, Raised ICP, Infection over region for lumbar puncture, Coagulopathy, cord compression, malformation
How would a patient with uncal herniation present?
headache, nausea vomitting, hypertension and bradycardia
How would a patient with cerebellar herniation present
loss of reflexes, seizure and hypertension
How would a patient with raised ICP present?
Nausea, vommitting, confusion/change in behaviour, papilloedema, CN III and IV palsy
List 5 complications of lumbar puncture
Headache (cuased by pulling on meninges and high innervation by trigeminal nerve), bloody traumatic tap, brain or cerebellar herniation, meningitis
Name 3 ligaments punctured during lumbar puncture
Supraspinatus, Interspinatus, Ligamentum flavum
Where does the spinal cord terminate?
L1-L2
How many and what are the pops in a)Lumbar puncture and b) Epidural ?
Lumbar puncture: 2 pops, ligamentum flavum –> dura mater and arachnoid mater
Epidural: 1 pop, ligamentum flavum
Where does the subarachnoid space terminate? How is it landmarked?
S2 landmarked by the PSIS and the sacral spinous process
Which structure is pierced causing bleeding in a traumatic tap? Where does this structure sit relative to spinous process?
Internal vertebral plexus - sits lateral, therefore deflection of the needle could cause trauma
What does the cauda equina supply?
motor function to hips, knees, ankles, feet, internal and external anal sphincter
Where is an adult LP performed (landmark)?
L3/L4 or L4/L5 -palpate the supracristal plane to identify L4 and go 1 spinous process level below to account for variability of spinal cord termination
Where is an LP performed in children? Why?
L4/L5 or S1/S2- their spinal cord terminates lower down due to their size
Why is the orientation of the bevel of needle important?
Bevel should be facing the ceiling with the patient lying on their side - aligns with the direction of the fibres making the dura so the fibres are split not cut; helps with healing, headache and leaking of fluid
How should a patient be positioned?
Lying or sitting with their knees in their chest to maximise space between vertebra.
Why do patients need to wear a sats probe when doing an LP
The position of flexed back could cause breathing problems as the chest cannot expand properly
What are 2 indications for epidural anaesthesia?
Childbirth and lower limb surgery
Where can epidurals be done?
anywhere along the length of the spinal cord however lumbar region has lowest risk of hitting the spinal cord
why should care with epidurals be taken?
Too much or wrong position inserting anaesthesia can cause paralysis of the diaphragm and cardiac dysfunction
Why does the angle of the needle have to become less angulated as you descend down the column?
The vertebral column angulation changes as you descend
Where are spinal anaesthesias performed?
L3/L4 to L5-S1
How is the level of anaesthesia controlled in a spinal block?
The tissues are bathed in anaesthetic, the level of anaesthesia is controlled by the density of the anaesthetic compared to the density of the CSF (anaesthetic is more dense so will sink to the bottom meaning more is needed for higher up blocks)
Can both an epidural and spinal block be done?
Yes, first advance needle into epidural space deliver anaesthetic and then into the subarachnoid space and deliver anaesthetic there
