SAH vs meningitis

Question 1

Describe the risk factors for SAH. (8)

Answer 1

Trauma, hypertension, smoking, alcohol, cocaine, FH, associated pHx (eg Marfans), aneurysms (Berry).

Question 2

Describe the treatment of SAH. (4)

Answer 2

Neuro referral for decompression and aneurysm clipping
Observation esp neuro exams
IV fluids (3l per day)
CCB

Question 3

Describe the complications of SAH. (6)

Answer 3

Death (50%)

Rebleed, cerebral ischaemia, hydrocephalus, seizure, disability.

Question 4

Explain the formation of a rash in meningitis. (6)

Answer 4

A non-blanching, macular papular rash that presents due to micro vascular thrombosis as a result of sluggish circulation, impaired fibrinolysis and impaired antithrombotic mechanisms.

Question 5

Describe risk factors for meningitis. (4)

Answer 5

CSF defects, spinal procedures, immunocompromisation (esp asplenia), crowded populations.

Question 6

Describe the treatments for meningitis. (4)

Answer 6

Supportive - pain relief, anti-pyretics.
IV ceftriaxone for bacterial, aciclovir for viral.
Dexamethasone to prevent hearing loss.

Question 7

Describe complications of meningitis. (11)

Answer 7

Sepsis, death, DIC, coma, cerebral oedema, raised ICP, SIADH, seizures, hearing loss, hydrocephalus, focal paralysis.

Question 8

Describe symtoms that are specific for meningitis. (7)

Answer 8

Fever, normal headache, photophobia, seizure, macular papular rash, shock, flu-ish.

Question 9

Describe common symtoms between SAH and meningitis. (4)

Answer 9

Altered consciousness, meningism, nuchal rigidity, headaches (different types though).

Question 10

Describe symptoms that are specific to SAH. (5)

Answer 10

Thunderclap headache, cardiac arrest, dizziness, history of bleeds, focal neurology.

Question 11

Describe investigations undertaken only in meningitis. (2)

Answer 11

Blood cultures, PCR.

Question 12

Describe investigations undertaken only in SAH. (1)

Answer 12

CT angiography.

Question 13

Describe investigations common to both SAH and meningitis. (2)
Explain why the order is important. (2)

Answer 13

CT scan and lumbar puncture.
You must do a CT first, unless meningitis is certain, because in a SAH, it will cause reactive herniation. A lumbar puncture is diagnostic in meningitis, but you would still need a CT, so do the CT first.

Question 14

Describe the lumbar puncture signs seen in bacterial meningitis. (4)

Answer 14

Cloudy fluid
High protein (>1g)
10-5000 polymorphic white cells
Low glucose

Question 15

Describe normal lumbar puncture signs. (6)

Answer 15

Opening pressure of 8-18 mmHg (25 mmH20)
Clear fluid
Low protein (<45 mg)
0-5 white cells 
Glucose of <60% serum
Minimal red cells.

Question 16

Describe viral meningitis signs on lumbar puncture. (4)

Answer 16

Cloudy fluid
Normal protein
15-1000 lymphocytes
Normal glucose.

Question 17

Describe the lumbar puncture signs of SAH. (6)

Answer 17

Increased opening pressure 
Bloody or xanthochromic appearance
High protein (>1g)
0-5 white cells (normal)
Normal glucose 
>500,000 red cells.

Question 18

Describe xanthochromia. (3)
Explain why it is more specific that blood in the CSF. (2)
Explain what you need to do to ensure results of CSF are as specific as can be. (3)

Answer 18

A sign found on lumbar puncture that occurs over 12 hours post SAH. Yellow colouring in CSF due to bilirubin presence.
More specific because can only be caused by SAH, whereas blood could be traumatic tap.
Take a second or third vial if the first is bloody (to allow for traumatic tap to stop bleeding). Wrap any xanthochromic vials in tin foil to stop UV depredation of bilirubin.