• Subarachnoid Haemorrhage
    Link:ceaccp.oxfordjournals.org/content/13/2/52.full.pdf
    • Cause of 5% of strokes, 10/100,000 people per yr - peak incidence 40-60yrs
    • 50% mortality, 25% die before reaching hospital. 1/3 of survivors will be dependent ant 1/2 will have cognitive impairment
    • Causes
      • Aneurysmal in 85% (genetic association with APCKD, Ehlers Danlos)
      • Rarer causes include AVMs & trauma
      • Contributed to by HT, smoking, cocaine use,
    • Clinical features & Ix
      • Classic thunderclap headache, neck stiffness, photophobia, LOC, focal neurology, possible cardiac arrest
      • CT will pick up 95% of cases on first day
      • LP at 12h after onset of symptoms may be indicated if CT is negative and SAH is still suspected to look for xanthochromia
      • A CT angio may look for the cause of SAH (most sensitive for >4mm in size) and a DSA may be done if further Ix is needed
    • Management
      • Initial assessment and management is similar to other forms of acute brain injury (CO2 4.5-5kPa, pO2 >13kPa)
      • Extreme hypertension must be managed (aim SBP<160, MAP <110) as well as hypotension (SBP <100 is detrimental)
      • Risk of re-bleed is highest in first 72h, and in females, and poor grade haemorrhages
        • Risk of re-bleeding reduced by minimising changes in transmural pressure
          • Avoid fluctuations in BP
            • Smooth anaesthesia
          • Avoid rapid rises/falls in ICP
            • Smooth anaesthesia
            • Coughing
            • Vasalva
            • ICD insertion
      • Clipping versus Coiling
        • ISAT trial favoured coiling over clipping
        • Slightly higher longer term risk of re-bleeding
        • Clipping still necessary for aneurysms with wide neck, or MCA aneurysms
    • Non-Neurological Complications
      • VTE
        • Multidisciplinary decision re: LMWH, all should have mechanical prophylaxis. LMWH usually started after the aneurysm is secure
      • Cardiogenic
        • Massive catecholamine surge with SAH leads to cardiac involvement in 50% of cases. Can cause ST elevation, AF, TWI, troponin rises, LVF and regional wall movement abnormalities
      • Pulmonary complications
        • 80% have impaired oxygenation at some time
        • Non-cardiogenic pulmaonry oedema, aspiration, ARDS, VAP, and cardiogenic pulmonary oedema are all causes
    • Ongoing management focuses on preventing delayed neurological deficit (DND)
      • Delayed cerebral ischaemia (DCI)
        • Occurs in 60% of patients
        • Risk highest on days 4-10
        • May be due to vasospasm but can occur independently of it
          • Vasospasm risks include poor grade SAH, IVH, smokers, large subarachnoid blood load
          • Vasospasm is seen in 70% of patients who have angiography, with 30% having clinical symptoms
          • May be asymptomatic or difficult to detect
          • Can be diagnosed with TCD, CTA, DSA or CT perfusion imaging
          • Treatments
            • Nimodipine, an L-type Ca channel antagonist
              • Mode of action not understood
              • 60mg 4 hourly (enterally when possible) for 3 weeks. Can be given IV on ITU.
            • HHH therapy (hypertension, hypervolaemia, haemodilution)
              • Not universally accepted as has poor evidence base
              • However, keep CPP >70
              • Aim for NORMOvolaemia
              • Traditional H’ct of 0.3 for haemodilation has also fallen out of favour
              • Aim for Hb 8-10
            • Magnesium
              • No benefit (IMASH trial)
            • Statins
              • No good evidence (STASH trial awaited)
            • Endovascular therapies
              • IA vasodilator therapy & angioplasty have been tried but prophylaxis is not recommended
            • Antiplatelets
              • Only indicated when a stent is deployed in the treatment of a ruptured aneurysm
      • Hydrocephalus
        • Occurs in 25% within the first 3 days
        • Higher risk in poor grade
        • Treatment requires insertion of EVD
      • Cerebral oedema
        • Medical management and surgical review
      • Fever
        • Common and associated with a worse outcome => treat
      • Seizures
        • Uncommon, and seen in 5% - may be a sign of a re-bleed
        • Prophylactic anticonvulsants not recommended
        • Treat seizures aggressively
      • Glucose/electrolyte abnormalities
        • Avoid hypoglycaemia, hyperglycaemia associated with a poorer outcome (4.5-11 target)
        • `Na disturbance is common due to SIADH, CSW or DI.