Investigations

Question 1

What does the history for headache involve?

Answer 1

• SOCRATES - how it started, when it comes on etc
• Previous episodes
• PMH - previous headaches or other illnesses
• Drug history - oral contraceptive pill, codeine
• FH e.g. migraine
• SH - smoker, caffeine, job, impact on life

Question 2

What are red flags for headaches?

Answer 2

• Blurred/swollen optic discs - papilloedema, sign of raised intracranial pressure
• Peripheral field loss, enlarged blind spots - raised intracranial pressure
• Sixth nerve palsy - false localising sign, giant cell arteritis
• Extensor plantar
• Ataxia - lesion in posterior fossa
• Oral hairy leukoplakia - Epstein-Barr virus
• Purpuric rash - meningococcal septicaemia
• Livedo reticularis - at risk of venous clots, antiphospholipid Ab syndrome, vasculitis

Question 3

What investigations can you do for a headache?

Answer 3

• CT - hydrocephalus
• MRI - large loculated mass (tumour)
• CSF manometer - measures pressure in brain
• Yellowish spinal fluid - xanthachromic fluid, seen when there is blood break down products in fluid - SAH
• Neutrophils in CSF - bacterial infection e.g. meningitis

Question 4

What is the most important sample for suspected meningitis?

Answer 4

CSF

Question 5

What investigations for meningitis should be done in a child under 1?

Answer 5

Full septic screen should include lumbar puncture as well as standard urine and blood cultures.

Question 6

What are the contraindications for lumbar puncture?

Answer 6

Any sign of raised ICP (papilloedema or focal neurological signs), coagulation defects and signs of infection at the site where needle is inserted.

Question 7

What does the colour of the CSF mean?

Answer 7

Normal - clear, colourless
Bacterial - turbid
Tuberculosis - turbid, vicous straw
Viral - clear

Question 8

What are other investigations for meningitis?

Answer 8

• Blood cultures
• Serology for viruses causing meningo-encephalitis
• Throat swab for Neisseria meningitides and streptococcus pneumoniae
• Urine pneumococcal antigen
• Kernig’s test - flex leg and neck, pain down back

Question 9

What tests can you do for encephalitis?

Answer 9

• CT or MRI - may show oedem of the temporal lobes

- Electroneceohalogram (EEG) - show characteristic slow waves

Question 10

What would CSF show for bacterial meningitis?

Answer 10

Increased WBC, increased neutrophils, increased protein, decreased glucose. Gram stain bacteria.

Question 11

What would CSF show for viral meningitis/encephalitis?

Answer 11

Decreased protein, normal glucose, increased WBC (normal monocytes). Gram stain negative, viral PCR might be positive.

Question 12

How do you measure ICP?

Answer 12

• EVD with strain-gauge pressure transducer
• Fibre optic intra-parenchymal transducer
• Air-pouch balloon
• Combined with temperature and microdialysis

Question 13

How do you calculate cerebral perfusion pressure?

Answer 13

CPP = ABP - ICP

Question 14

What are the investigations for giant cell arteritis?

Answer 14

• ESR, CRP are increased
• Increased platlets
• increased ALP, decreased Hb