WFNS SAH WFNS clinical grading of aneurysmal subarachnoid hemorrhage

{
  "categories": [
    {
      "outcome_code": "1",
      "gcs_total": "15",
      "major_focal_neurologic_deficit": "absent"
    },
    {
      "outcome_code": "2",
      "gcs_total": "13_to_14",
      "major_focal_neurologic_deficit": "absent"
    },
    {
      "outcome_code": "3",
      "gcs_total": "13_to_14",
      "major_focal_neurologic_deficit": "present"
    },
    {
      "outcome_code": "4",
      "gcs_total": "7_to_12",
      "major_focal_neurologic_deficit": "present_or_absent"
    },
    {
      "outcome_code": "5",
      "gcs_total": "3_to_6",
      "major_focal_neurologic_deficit": "present_or_absent"
    }
  ],
  "applicability": {
    "intended_use": "Standardized bedside communication of clinical severity in a patient with subarachnoid hemorrhage, classically aneurysmal SAH.",
    "classification_unit": "one_patient_at_one_explicit_clinical_timepoint_after_initial_resuscitation",
    "required_inputs": [
      "reliable_Glasgow_Coma_Scale_total_and_components",
      "presence_or_absence_of_major_focal_neurologic_deficit",
      "assessment_timepoint",
      "confounder_status"
    ],
    "outside_scope": [
      "grading_from_CT_alone",
      "quantifying_subarachnoid_blood_burden",
      "diagnosing_the_aneurysm",
      "predicting_delayed_cerebral_ischemia_from_grade_alone",
      "automatic_treatment_or_futility_decision"
    ]
  },
  "assignment_algorithm": [
    "Stabilize airway, breathing and circulation and identify immediately reversible examination confounders.",
    "Record eye, verbal and motor GCS components plus the total at a named timepoint; do not infer a score hidden by sedation or paralysis.",
    "Record whether a major focal neurologic deficit such as aphasia or hemiparesis is present when the examination can establish it.",
    "Map GCS 15 without a major deficit to 1; GCS 13-14 without versus with a major deficit to 2 versus 3; GCS 7-12 to 4; and GCS 3-6 to 5.",
    "If reliability is materially limited, return the observed facts and a provisional or unassignable state rather than manufacturing a definitive grade."
  ],
  "decisive_boundaries": {
    "grade_1_versus_2": "GCS 15 is grade 1 only when a major focal deficit is absent; GCS 14 is already within grade 2 or 3.",
    "grade_2_versus_3": "Both grades use GCS 13-14. Absence of a major focal deficit is grade 2 and presence is grade 3; never invert this axis.",
    "grade_3_versus_4": "GCS 13 remains grade 2 or 3 according to deficit; GCS 12 is grade 4 regardless of deficit.",
    "grade_4_versus_5": "GCS 7 is grade 4 and GCS 6 is grade 5; focal-deficit status does not move either band."
  },
  "examination_reliability_gate": {
    "confounders_to_record": [
      "sedatives_or_anesthetics",
      "endotracheal_intubation_limiting_verbal_score",
      "neuromuscular_blockade",
      "postictal_state_or_ongoing_seizure",
      "hydrocephalus",
      "hypoxia_or_hypotension",
      "metabolic_or_temperature_derangement",
      "language_or_preexisting_neurologic_limit"
    ],
    "intubated_verbal_component": "Use the locally declared GCS convention and expose the verbal limitation; do not silently assign a normal verbal score.",
    "timepoint_rule": "A grade before resuscitation, after resuscitation, after cerebrospinal-fluid diversion and after sedation are different observations. Preserve the timepoint and any change rather than overwriting the trajectory.",
    "focal_deficit_rule": "Do not declare absence of a major deficit when coma, paralysis or an otherwise unreliable examination prevents testing."
  },
  "imaging_and_system_boundaries": {
    "CT": "CT establishes hemorrhage distribution and complications but cannot provide the clinical GCS-plus-deficit WFNS grade.",
    "original_Fisher_or_modified_Fisher": "These are CT blood-distribution frameworks and must be calculated separately from their own imaging inputs; no numeric crosswalk to WFNS is valid.",
    "Hunt_Hess": "Hunt-Hess uses different clinical descriptors. A historical correspondence is not a one-to-one conversion and must not replace direct grading.",
    "aneurysm_status": "WFNS does not identify aneurysm site, rupture source, rebleeding, hydrocephalus, vasospasm or delayed cerebral ischemia; return those as separate facts."
  },
  "current_management_boundary": {
    "all_grades": "Activate specialized aneurysmal-SAH care, identify and secure the ruptured aneurysm as early as feasible, preferably within 24 hours when appropriate, and apply current neurocritical-care guidance. The WFNS numeral is communication context rather than an order.",
    "poor_grade": "Grades 4-5 do not establish futility or justify withholding aneurysm treatment. Resuscitation, reversible causes, age, comorbidities, hemorrhage pattern, brain injury, patient values and multidisciplinary judgment determine candidacy and timing.",
    "prohibited_legacy_inference": "Do not reproduce the historical rule that grades above 3 should simply wait for surgery; contemporary care evaluates early aneurysm securing across grades."
  },
  "risk_interpretation": {
    "population_gradient": "Higher grades are associated with worse outcomes in groups, but the scale is not a calibrated patient-level probability model.",
    "confounding": "Sedation, intubation, hydrocephalus, seizures, resuscitation state and timing can shift the observed grade and materially bias prognosis.",
    "prohibited_inferences": [
      "individual_mortality_percentage",
      "individual_functional_outcome_percentage",
      "treatment_benefit_from_grade_alone",
      "neurologic_futility"
    ]
  },
  "agent_output_contract": [
    "Return the examination timepoint and reliability before the grade.",
    "Return the exact GCS components and total plus major focal-deficit status.",
    "Name the decisive boundary, especially the grade 2 versus 3 deficit split.",
    "Keep CT blood burden, aneurysm status, hydrocephalus and complications as separate outputs.",
    "Separate population-level severity context from individualized prognosis and treatment."
  ],
  "missing_input_behavior": [
    "Without a reliable GCS total and components, do not assign a definitive WFNS grade.",
    "With GCS 13-14 but unknown deficit status, return a grade 2-or-3 conditional range and request a reliable focal examination.",
    "If a query supplies CT findings only, route to the appropriate CT hemorrhage framework and explicitly withhold WFNS.",
    "If the examination changes after resuscitation or cerebrospinal-fluid diversion, retain both grades with their timepoints."
  ],
  "supporting_sources": [
    {
      "role": "primary_scale",
      "citation": "Drake et al. J Neurosurg. 1988;68:985-986",
      "doi": "10.3171/jns.1988.68.6.0985",
      "pmid": "3131498"
    },
    {
      "role": "current_US_care_context",
      "citation": "Hoh et al. Stroke. 2023;54:e314-e370",
      "doi": "10.1161/STR.0000000000000436"
    },
    {
      "role": "current_European_care_context",
      "citation": "Vergouwen et al. Eur Stroke J. 2026",
      "doi": "10.1093/esj/aakag043",
      "pmcid": "PMC13151661"
    }
  ],
  "source_locator": "Drake et al. 1988, DOI 10.3171/jns.1988.68.6.0985, original table; Rosen and Macdonald 2013, PMC3621041, Table 3; Hoh et al. 2023, DOI 10.1161/STR.0000000000000436, aneurysm-treatment timing; Vergouwen et al. 2026, PMC13151661, current multidisciplinary aSAH care."
}