Grade a real, time-stamped clinical examination only. Keep CT blood burden separate, expose confounders and uncertainty, and never translate a poor Hunt-Hess grade into autonomous treatment limitation or futility.
{
"categories": [
{
"outcome_code": "1",
"consciousness": "alert",
"headache": "absent_or_mild",
"nuchal_rigidity": "absent_or_slight",
"focal_deficit": "absent"
},
{
"outcome_code": "2",
"consciousness": "alert",
"headache": "moderate_to_severe",
"nuchal_rigidity": "present",
"focal_deficit": "none_except_possible_cranial_nerve_palsy"
},
{
"outcome_code": "3",
"consciousness": "drowsy_or_confused",
"headache": "not_category_defining",
"nuchal_rigidity": "not_category_defining",
"focal_deficit": "none_or_mild"
},
{
"outcome_code": "4",
"consciousness": "stupor",
"headache": "not_assessable_or_not_category_defining",
"nuchal_rigidity": "not_category_defining",
"focal_deficit": "moderate_to_severe_hemiparesis_possible_early_decerebrate_rigidity_and_vegetative_disturbance"
},
{
"outcome_code": "5",
"consciousness": "deep_coma",
"headache": "not_assessable",
"nuchal_rigidity": "not_category_defining",
"focal_deficit": "decerebrate_rigidity_with_moribund_appearance_or_failing_vital_centers"
}
],
"applicability": {
"intended_use": "Describe the bedside clinical condition of a patient with ruptured aneurysmal subarachnoid hemorrhage at a defined timepoint.",
"required_input": "Direct neurologic examination including level of consciousness, orientation, meningeal symptoms/signs, cranial nerves and focal motor deficit.",
"not_an_imaging_scale": "Do not derive Hunt-Hess from CT, CTA, MRI or angiography. CT blood burden and intraventricular hemorrhage belong in a radiologic scale such as modified Fisher and are reported separately.",
"outside_scope": [
"unruptured_aneurysm_risk",
"nonaneurysmal_headache_without_SAH",
"CT_blood_burden",
"delayed_cerebral_ischemia_diagnosis",
"standalone_long_term_outcome_prediction",
"treatment_selection_by_grade_alone"
]
},
"assessment_time_and_provenance": {
"preferred_timepoint": "Record the grade at admission or another explicitly named time after initial stabilization; never mix findings from different examinations into one grade.",
"required_provenance": [
"assessment_datetime",
"examiner_or_source_note",
"before_or_after_airway_and_sedating_medication",
"Glasgow_Coma_Scale_when_available",
"neurologic_change_since_prior_exam"
],
"trajectory_rule": "Store serial grades with their timestamps. A later grade must not overwrite the admission state or conceal deterioration or improvement."
},
"confounder_gate": {
"potentially_invalidating": [
"sedation",
"general_anesthesia",
"intubation_without_reliable_pre_intubation_exam",
"neuromuscular_blockade",
"postictal_state",
"active_seizure",
"intoxication",
"major_metabolic_derangement",
"hypoxia_or_hypotension",
"severe_analgesic_effect",
"language_or_hearing_barrier"
],
"disease_mediated_but_important": [
"acute_hydrocephalus",
"large_intraparenchymal_hematoma",
"rebleeding",
"raised_intracranial_pressure"
],
"rule": "If consciousness or motor findings cannot be attributed reliably to the SAH clinical state, return grade indeterminate/confounded and preserve the observed examination plus cause; do not manufacture a grade."
},
"grading_algorithm": [
{
"step": 1,
"state": "deep_coma_with_decerebrate_rigidity_and_moribund_or_failing_vital_centers",
"output": "5"
},
{
"step": 2,
"state": "stupor_with_moderate_to_severe_hemiparesis_with_possible_early_decerebrate_rigidity_or_vegetative_disturbance",
"output": "4"
},
{
"step": 3,
"state": "drowsiness_or_confusion_with_or_without_mild_focal_deficit",
"output": "3"
},
{
"step": 4,
"state": "alert_with_moderate_to_severe_headache_and_nuchal_rigidity_and_no_deficit_other_than_possible_cranial_nerve_palsy",
"output": "2"
},
{
"step": 5,
"state": "asymptomatic_or_alert_with_mild_headache_and_at_most_slight_nuchal_rigidity_and_no_deficit",
"output": "1"
},
{
"step": 6,
"state": "features_do_not_fit_one_grade_or_required_exam_is_missing",
"output": "indeterminate_or_adjacent_grade_range"
}
],
"boundary_rules": {
"grade_1_2": "Moderate/severe headache plus definite nuchal rigidity supports grade 2; mild headache and at most slight rigidity supports grade 1. A cranial-nerve palsy may still be grade 2 but any non-cranial focal deficit does not fit grade 2.",
"grade_2_3": "Drowsiness or confusion moves the patient beyond grade 2 even when focal deficit is absent. An alert patient with a mild non-cranial focal deficit does not cleanly fit canonical grade 2 and should not be forced without documenting the conflict.",
"grade_3_4": "Drowsiness/confusion and at most mild focal deficit is grade 3; stupor or moderate/severe hemiparesis is grade 4.",
"grade_4_5": "Stupor with severe deficit is grade 4; deep coma with established decerebrate rigidity and moribund/failing-vital-center appearance is grade 5.",
"worst_feature_rule": "Use the poorest defensible category-defining clinical feature at the same assessment time, while retaining all observed findings and confounders.",
"discordance_rule": "When consciousness and motor severity point to nonadjacent grades, report the discordance and seek reassessment rather than averaging the grade."
},
"historical_variant_boundary": {
"systemic_or_vasospasm_modifier": "Historical formulations add one grade for serious systemic disease or severe angiographic vasospasm. Because definitions and modern application vary, apply this only when the reporting protocol explicitly requests the original modifier, store the unmodified clinical grade, name the modifier and never exceed grade 5.",
"grade_0_and_1a": "Some extended tables include grade 0 for an unruptured aneurysm and grade 1a for a fixed neurologic deficit without acute meningeal/brain reaction. They are outside this canonical 1-5 outcome set and must be identified as variants, not silently mapped to grade 1 or 2."
},
"clinical_and_management_context": {
"emergency_rule": "Suspected or confirmed aneurysmal SAH requires emergency neurovascular and neurocritical management regardless of Hunt-Hess grade.",
"treatment_rule": "The grade does not decide aneurysm securing, clipping versus coiling, blood-pressure strategy, nimodipine, hydrocephalus treatment, seizure care, delayed-cerebral-ischemia surveillance or ICU intensity by itself.",
"current_context": "Use current AHA/ASA aneurysmal-SAH guidance together with aneurysm status, rebleeding risk, hydrocephalus/ICP, cerebral ischemia, systemic complications, age, baseline function and goals of care.",
"poor_grade_not_futility": "Grades 4 and 5 denote a poor initial clinical state but are not a declaration of futility and must not autonomously trigger treatment limitation or withdrawal of life support."
},
"prognosis_and_reliability": {
"direction": "Higher grade is associated with worse outcomes at the population level, but the scale is ordinal and does not yield a calibrated individual probability.",
"cohort_example": "In one prospective single-center cohort of 1,200 consecutive spontaneous SAH patients enrolled from 1996-2009, in-hospital mortality was 3 percent for grades 1-2 combined, 9 percent for grade 3, 24 percent for grade 4 and 71 percent for grade 5.",
"cohort_caveat": "Those figures reflect one historical-center cohort, included spontaneous aneurysmal and nonaneurysmal SAH, and were affected by subsequent complications and life-support decisions. They are context, not a bedside forecast or current benchmark.",
"interobserver_evidence": "In a 50-patient, 103-paired-assessment study, Hunt-Hess had weighted kappa 0.48 (95% CI 0.36-0.59), lower than WFNS 0.60 and PAASH 0.64; subjective terms therefore require explicit examination provenance.",
"complementary_data": "Report GCS and, when relevant, WFNS/PAASH, age, baseline status, modified Fisher/CT findings, aneurysm features and systemic physiology rather than treating Hunt-Hess as a complete prognostic model."
},
"agent_output_contract": [
"exact_Hunt_Hess_grade_or_indeterminate_state",
"assessment_datetime_and_pre_or_post_intervention_context",
"consciousness_orientation_headache_nuchal_rigidity_cranial_nerve_and_motor_findings",
"GCS_when_available",
"all_examination_confounders",
"separate_modified_Fisher_or_other_imaging_grade_if_available",
"serial_trajectory_without_overwriting_prior_grade",
"urgent_aSAH_context_without_grade_only_treatment_or_futility_claim"
],
"missing_input_behavior": [
"If there is no direct or reliably documented clinical examination, do not infer Hunt-Hess from CT appearance; return clinical grade unavailable.",
"If sedation, intubation or another confounder obscures the examination and no pre-confounder state exists, return confounded rather than grade 4 or 5.",
"If headache/rigidity distinguish grades 1 and 2 but are undocumented, return 1-versus-2 unless another feature establishes a higher grade.",
"If alertness versus drowsiness/confusion is unclear, retain 2-versus-3 uncertainty and request a time-stamped reassessment.",
"If the patient changes clinically, create a new timepoint rather than retroactively changing the earlier grade."
],
"supporting_sources": [
{
"role": "primary_scale",
"citation": "Hunt and Hess. J Neurosurg. 1968;28:14-20",
"doi": "10.3171/jns.1968.28.1.0014",
"pmid": "5635959"
},
{
"role": "current_care_context",
"citation": "Hoh et al. Stroke. 2023;54:e314-e370",
"doi": "10.1161/STR.0000000000000436",
"pmid": "37212182"
},
{
"role": "interobserver_reliability",
"citation": "Degen et al. Stroke. 2011;42:1546-1549",
"doi": "10.1161/STROKEAHA.110.601211",
"pmid": "21527761"
},
{
"role": "cohort_risk_context",
"citation": "Lantigua et al. Crit Care. 2015;19:309",
"doi": "10.1186/s13054-015-1036-0",
"pmcid": "PMC4556224"
}
],
"source_locator": "Hunt and Hess 1968, DOI 10.3171/jns.1968.28.1.0014, pp. 14-20 for the original clinical categories and historical modifier; Hoh et al. 2023 AHA/ASA guideline, DOI 10.1161/STR.0000000000000436 for current aneurysmal-SAH management context; Degen et al. 2011 abstract/results for weighted kappa; Lantigua et al. 2015, PMC4556224, Abstract and Table 2 for cohort mortality and its determinants."
}