Subarachnoid hemorrhage

Clinical presentation
==== Hunt-Hess Scale ====

==== World Federation of Neurological Surgeons (WFNS) Scale ====

Imaging
==== Fisher grade ==== There is no score in neurocritical care more falsely understood and defined than the Fisher score. Fisher et al. defined their imaging-based score using measurements of vertical layers of blood using a ruler on standard-sized printed images ("transparencies or hard copies" per their paper). We no longer have these standard printings, and therefore the application of their scale to modern imaging is quite suspect. Nevertheless, actual electronic measurements of SAH thickness on modern-day PACS systems is often used but the 1 mm threshold for Fisher score of 2 vs 3 is still used, which is entirely invalid. Moreover, the classification of Fisher score 4 is problematic, as it includes patients with either "diffuse" thin blood or no blood at all in the cisterns, but who had ICH or IVH, and only enrolled 5 of these patients, who all had low risk of vasospasm, which makes the scale not ordinal. While the authors should be credited with development of the first prediction model of vasospasm, we have far better and ordinal scales available now which should be used instead, so the original Fisher score should be retired. ==== Modified Fisher scale ==== The modified Fisher Score (mFS) was developed initially by Claassen et al., who specifically used the parameter of bilateral IVH (not unilateral) in the score. However, in Frontera et al. they subsequently described the utility of the scale using any IVH in the score. This scale is more ordinal than the original Fisher score (although mFS 2-3 confer similar rates of DCI), and is measurable on modern imaging. It should be used in lieu of the original Fisher score.

Hijdra score
This score is calculated by measuring the amount of blood present in various cisterns. 0 = no blood, 1 = small amount of blood, 2 = moderately filled with blood, 3 = completely filled with blood

==== Subarachnoid Hemorrhage Early Brain Edema Score (SEBES) ====

Nimodipine
Nimodipine should be administered to all SAH patients within 24 hours unless there is a clear contraindication. This is a Neurocritical Care Society Clinical Performance Measure.

Delayed hydrocephalus
Some patients may initially pass a clamp trial of an external ventricular drain and then have it removed, only to develop delayed hydrocephalus requiring a subsequent ventriculoperitoneal shunt (VPS). In a retrospective series of 94 patients with SAH requiring an EVD who survived hospitalization, 65 patients (69%) were able to have the EVD removed prior to discharge. However, 10 of these patients (15%) developed delayed hydrocephalus and ultimately required VPS placement. In a large study using administrative data of 8,889 patients discharged after SAH, only 116 (1.3%) developed delayed hydrocephalus. More than 90% of cases of delayed hydrocephalus occurred within 1 year of discharge, the majority occurring within 6 months.

Risk factors include: Shunt complications are common in these patients. In one series of 116 patients they occurred in 18% of patients, including inadequate shunting due to valve malfunction (9.5%), shunt infection (6.9%), exposed hardware (2.6%), wound breakdown (2.6%), IVH or hemorrhage along the shunt tract (3.5%), injury to peritoneal or thoracic structures (1.7%), pseudomeningocele (1.7%), and CSF pseudocyst (0.9%).
 * Fisher grade (higher): OR 7.74 (95% CI 4.47-13.41, n=3,246, from meta-analysis of 10 studies).
 * Acute hydrocephalus at admission: OR 5.67 (95% CI 3.96-8.12, n=6,075, from meta-analysis of 7 studies). However, this was not significant in another study (n=888) with multivariable analysis. It is rare to have delayed hydrocephalus without requiring temporary ventriculostomy placement in the hospital, happening in only 0.9% of patients in a large series (n=8,889)
 * In-hospital complications: OR 4.91 (95% CI 2.79-8.64, n=13,721, from meta-analysis of 6 studies).
 * IVH: OR 3.93 (95% CI 2.80-5.52, n=13,693, from meta-analysis of 7 studies) This was also seen in another study of 888 patients (aOR 5.02, 95% CI 1.70-14.83).
 * Hunt-Hess or WFNS score at admission (higher): Hunt-Hess OR 3.25 (95% CI 2.51-4.21, n=6,705, from meta-analysis of 11 studies). In a study of 888 patients, a higher Hunt-Hess score was not significant, but a higher WFNS score was (aOR 1.46, 95% CI 1.24-1.72).
 * Discharge to skilled nursing facility: HR 2.9 (95% CI 1.8-4.6, n=8,889)
 * Surgical aneurysm treatment: OR 2.34 (95% CI 1.35-4.07, n=888) and HR 2.0 (95% CI 1.2-3.3, n=8,889)
 * Rebleeding: OR 2.21 (95% CI 1.24-3.95, n=767, from meta-analysis of 2 studies).
 * Angiographic vasospasm (aOR 2.16, 95% CI 1.27-3.69, n=888), and seen in another study as well (n=489).
 * Posterior circulation aneurysm location: OR 1.85 (95% CI 1.35-2.53, n=20,477, from meta-analysis of 11 studies).
 * Age ≥ 60 years: OR 1.81 (95% CI 1.50-2.19, n=4,256, from meta-analysis of 2 studies), or older age in general (aOR 1.04, 95% CI 1.02-1.06, n=888).
 * Third ventricular size (larger)
 * On final study, diameter: aOR 1.59 (95% CI 1.11-2.6, n=91)
 * On initial study, volume: aOR 1.719 (95% CI 1.07-2.76, n=217)
 * Mechanical ventilation: HR 1.7 (95% CI 1.1-2.8, n=8,889)
 * Initial CSF protein concentration (higher): aOR 1.02 (95% CI 1-1.04, p=0.023, n=91). This value was 130 mg/dL on average in those requiring late VPS, and 43 in those not requiring VPS.
 * Failure of clamp trials: especially failure of more than one (possibly, univariate analysis)

Seizures
Seizures occur in approximately 20% of patients at onset of SAH. Long-term epilepsy occurs in approximately 4-12% of patients and are more common in those with seizure at onset.

Possible risk factors include:
 * Lab values
 * Low serum iron (<9.9 mmol/L), aOR 4.76 (95% CI 1.75-12.99), 82% sensitive, 65% specific, AUC 0.71)
 * Anemia (<11.5 g/dL), aOR 1.03 (95% CI 1.01-1.06), 61% sensitive, 78% specific, AUC 0.68)
 * Imaging markers
 * Higher SAH clot burden with Hijdra score ≥18 (aOR 2.76, 95% CI 1.39-5.49)
 * Subdural hematoma (aOR 5.67, 96% CI 1.56-20.57)

Myocardial stunning
Risk factors include: Diagnosis
 * Higher Hunt-Hess Grade
 * Higher WFNS Grade
 * Lower Glasgow Coma Scale (GCS)
 * TTE
 * Troponin elevation
 * Heart rate variability measures using a machine learning approach.

Pituitary atrophy
Patients with SAH are associated with lower pituitary gland volume early after SAH (16 days on average) and 1 year after SAH compared with age-matched controls. Some patients with SAH gain pituitary volume over the first year of hemorrhage while others have a decrease. Decreases were associated with impaired self-motivation.

Patient factors

 * WFNS scale
 * Admission WFNS scale of 4-5 was associated with unfavorable outcome (mRS 3-6) with aOR 5.441 (95% CI 2.771-10.683) in one retrospective study of 196 patients. Higher WFNS scale was also associated with mRS 3-6 in another study of 888 patients.
 * Modified Fisher scale
 * Admission mFS of 3-4 was associated with unfavorable outcome (mRS 3-6) with aOR 4.116 (95% CI 1.852-9.148) in one retrospective study of 196 patients.
 * Hypertension
 * A 2018 study suggested that hypertension was associated with improved outcomes in aSAH, but this study did not include patients who died before reaching the hospital. Including those patients, hypertensive patients have significantly worse survival after aSAH.
 * Shunt placement: aOR 5.34 (95% CI 2.86-99) for mRS 3-6 in an 888 patient study
 * Shunt infection: aOR 10.16 (95% CI 1.10-93.49) for mRS 3-6 in an 888 patient study
 * Age (older): aOR 1.05 (95% CI 1.03-1.07) for mRS 3-6 in an 888 patient study

Lab factors

 * Serum
 * Alkaline phosphatase
 * Higher levels of alkaline phosphatase are associated with unfavorable outcome (mRS 3-6) with aOR of 1.019 (95% CI 1.002-1.036), although this comes from one study with n=196, so data is limited.
 * Magnesium
 * Lower admission magnesium level is associated with greater severity of initial SAH as graded by mFS.
 * CSF
 * Soluble vascular endothelial-cadherin (sVE-cadherin)
 * This may shift microglia to a more proinflammatory state and cause more neuroinflammation. Higher CSF levels are associatedd with a higher risk of poor outcome (mRS 3-6) in patients with SAH.

Patient factors

 * Smoking
 * Several studies suggested that smoking was associated with improved outcomes in aSAH, but these studies did not include patients who died before reaching the hospital. Including those patients, smokers have significantly worse survival after aSAH.

GWTG Stroke score (2013)
This score as derived and validated from an extremely large sample of over 300,000 stroke patients (all types) from the Get With the Guidelines - Stroke Database. It included 8,664 patients with SAH, for which the AUROC for mortality was 0.89.

==== RAISE Score for Prediction of Mechanical Ventilation (2022) ====

Admission unit
Admission to a dedicated unit (stroke unit, ICU) with neuroscience physician and nursing expertise for all subarachn oid hemorrhage patients is a Neurocritical Care Society Clinical Performance Measure.