You are the Short Stay/Observation Unit Consultant in a tertiary centre. Megan is a patient that you review on your morning ward round. She presented the previous afternoon to your ED with a sudden onset headache in the occipital area, which she described as “the worst headache ever” which then resolved after one hour. There is no significant past medical history or family history. She takes no regular medications. There was no reduction in conscious state or focal neurology. A plain CT was performed yesterday evening and it is normal. There are no other contra-indications to a lumbar puncture. In the notes from the previous evening the Registrar who initially assessed Megan indicated that they have had a preliminary discussion about undertaking an LP and she expressed some reluctance after hearing it involved putting a “needle in her spine”.
Please discuss the indications and pros/cons of undertaking an LP , then go on to discuss the risks of the procedure and outcomes of both positive and negative results.
You are concerned that the doctor the yesterday evening said you needed a “needle in the spine” to find the cause of your headache. You feel completely fine now, and you are reassured that the scan they did last night was normal. You are “really worried about the needle damaging your spinal cord”.
Your sister had a really bad headache after having an epidural and you are worried that you will have the same.
No prompts are given.
Candidates must clearly explain that:
They are concerned that the headache the previous day was a ‘warning bleed’ from an SAH
The intention is to diagnose a warning bleed so that a serious/life threatening large bleed may be prevented
Better candidates will explain in lay persons terms what an aneurysm is, the fact that they are uncommon, but if there has been a bleed caused by an aneurysm there can be treatment to reduce the chances of a catastrophic bleed
The plain CT showed that there was no evidence of blood, but this doesn’t entirely exclude a SAH
Better candidates may discuss evidence regarding use of CT within 6 hours of onset of headache
May discuss the limitations:
Need expert Neuro-Radiologist opinion on CT
Single large Canadian study (BMJ), not yet replicated
Current “gold standard” is still LP to test for Xanthochromia
If candidates discuss the use of CT Cerebral Angiogram in the investigation of ?SAH prior to LP they must indicate that:
May find asymptomatic Aneurysms (present in 1% of population)
May have SAH and aneurysm not detected due to vasospasm
Will require LP to test for Xanthochromia eg. Has the aneurysm bled
Candidates must describe the procedure
Reassure that needle does not go “into the spinal cord”
Discuss the risks
Local: bleeding/infection in subarachnoid space, rarely meningitis
Neuropraxia: in rare cases can be permanent
Headache: increased risk if multiple attempts, larger bore needle, non-pencil point needle