Headache after SAH increases in intensity during first 7d after onset.
- factors that contribute to vasopasm may also lead to headache
- chemical irritation of blood on meninges and subarachnoid space can cause pain
- infiltration of immune cells, immune activation and inflammatory cytokines contributes to pain
- alterations in brain perfusion from vasopasm may also be a factor
- Fioricet largely ineffective, ?associated with early vasospasm
- In SAH patients, elevated Mg levels associated with less severe headache, – IV magnesium therapy may provide relief for SAH patients?
- Magnesium is a non-competitive antagonist of voltage-dependent calcium channels and NMDA receptor. Blocking of NMDA receptor is involved in pain modulation – prevents induction of central pain sensitisation.
- The effect of magnesium on headache after SAH is unknown.
- Most studies use dose of 1-2G IV bolus, in the study referenced below, higher daily dose (16G MgSO4 for a sustained period – nonbolus) was given.
- Diarrhea is a common side effect.
- Fioricet 1 q4h
- tramadol 100 q6h
- valproate 500 IV q8h x3d
- metoclopramide 5-10mg q6h x 3d
- Mg 2G IV once
*monitor QT interval
Dorhout Mees, S., Bertens, D., van der Worp, H., Rinkel, G., & van den Bergh, W. (2009). Magnesium and headache after aneurysmal subarachnoid haemorrhage. Journal Of Neurology, Neurosurgery & Psychiatry, 81(5), 490-493. doi: 10.1136/jnnp.2009.181404
Swope, R., Glover, K., Gokun, Y., Fraser, J., & Cook, A. (2014). Evaluation of headache severity after aneurysmal subarachnoid hemorrhage. Interdisciplinary Neurosurgery, 1(4), 119-122. doi: 10.1016/j.inat.2014.07.003