Cookbook 333: Offline Clinical Neurocritical Care Subarachnoid Hemorrhage, Hunt-Hess & TCD Engine

"""
Cookbook 333: Offline Neurocritical Care Subarachnoid Hemorrhage, Hunt-Hess & TCD Engine
OpenPHR Clinical AI Working Group (https://openphr.org)
"""

import math
import numpy as np
import pandas as pd
from typing import Dict, List, Tuple, Optional
from dataclasses import dataclass

@dataclass
class SAHPatientTelemetry:
    patient_id: str
    age_years: float = 54.0
    day_post_ictus: int = 7 # Day 7 (Peak vasospasm window: Days 4-14)
    # Clinical Neurological Examination Telemetry
    glasgow_coma_scale: int = 14 # GCS 3-15
    headache_severity: str = "Severe" # "None/Mild", "Moderate", "Severe"
    nuchal_rigidity_present: bool = True
    cranial_nerve_palsy: bool = True # e.g. CN III oculomotor palsy
    motor_deficit_present: bool = False # Hemiparesis/hemiplegia
    deep_coma_or_decerebrate: bool = False
    # Radiologic CT Subarachnoid Hemorrhage Telemetry
    ct_thick_cisternal_clot_ge_1mm: bool = True # Modified Fisher: Thick SAH >= 1mm
    ct_bilateral_intraventricular_hemorrhage: bool = True # Modified Fisher: Bilateral IVH
    # Transcranial Doppler (TCD) Telemetry
    tcd_mca_mean_flow_velocity_cm_s: float = 215.0 # cm/s (>= 200 = Severe Vasospasm)
    tcd_ica_extracranial_velocity_cm_s: float = 32.0 # cm/s
    # Aneurysm Treatment Status & Hemodynamics
    aneurysm_secured: bool = True # Coiled / Clipped
    current_sbp_mmhg: float = 135.0 # mmHg
    current_map_mmhg: float = 88.0 # mmHg
    is_euvolemic: bool = True
    # Active Medication Warnings
    active_nimodipine_route: str = "Enteral / Oral" # "Enteral / Oral" vs "Intravenous" (🚨 FATAL!)

@dataclass
class SAHEvaluationReport:
    patient_id: str
    hunt_hess_grade: int # 1 - 5
    hunt_hess_description: str
    wfns_grade: int # 1 - 5
    modified_fisher_grade: int # 0 - 4
    modified_fisher_vasospasm_risk: str
    tcd_lindegaard_ratio: float
    tcd_vasospasm_interpretation: str
    nimodipine_order_protocol: List[str]
    dci_hemodynamic_management: List[str]
    safety_sentinels: List[str]
    clinical_ncs_aha_directive: str

class SubarachnoidHemorrhageDecisionEngine:
    """
    Offline clinical engine for Hunt-Hess / WFNS grading, Modified Fisher CT staging,
    TCD Lindegaard ratio computation, and delayed cerebral ischemia (DCI) management.
    """

    def calculate_hunt_hess_grade(self, d: SAHPatientTelemetry) -> Tuple[int, str]:
        if d.deep_coma_or_decerebrate:
            return 5, "Grade 5: Deep coma, decerebrate posturing, moribund appearance."
        elif d.glasgow_coma_scale <= 8 or d.motor_deficit_present:
            return 4, "Grade 4: Stupor, moderate-to-severe hemiparesis, vegetative disturbance."
        elif d.glasgow_coma_scale <= 13 or d.headache_severity == "Severe":
            return 3, "Grade 3: Drowsiness, confusion, or mild focal neurological deficit."
        elif d.headache_severity in ["Moderate", "Severe"] or d.nuchal_rigidity_present or d.cranial_nerve_palsy:
            return 2, "Grade 2: Moderate-to-severe headache, nuchal rigidity, cranial nerve palsy (no other deficit)."
        else:
            return 1, "Grade 1: Asymptomatic or mild headache and slight nuchal rigidity."

    def calculate_wfns_grade(self, gcs: int, motor_deficit: bool) -> int:
        if gcs == 15 and not motor_deficit:
            return 1
        elif gcs in [13, 14] and not motor_deficit:
            return 2
        elif gcs in [13, 14] and motor_deficit:
            return 3
        elif 7 <= gcs <= 12:
            return 4
        else:
            return 5

    def calculate_modified_fisher_scale(self, d: SAHPatientTelemetry) -> Tuple[int, str]:
        thick = d.ct_thick_cisternal_clot_ge_1mm
        ivh = d.ct_bilateral_intraventricular_hemorrhage

        if thick and ivh:
            return 4, "Grade 4: Thick cisternal SAH (>= 1 mm) WITH bilateral IVH -> HIGHEST DCI Vasospasm Risk (~38-42% incidence)."
        elif thick and not ivh:
            return 3, "Grade 3: Thick cisternal SAH (>= 1 mm) WITHOUT IVH -> High DCI Vasospasm Risk (~30% incidence)."
        elif not thick and ivh:
            return 2, "Grade 2: Thin SAH (< 1 mm) WITH bilateral IVH -> Moderate DCI Vasospasm Risk (~20% incidence)."
        else:
            return 1, "Grade 1: Thin SAH (< 1 mm) WITHOUT IVH -> Low DCI Vasospasm Risk (~12% incidence)."

    def evaluate_tcd_lindegaard(self, mca_vel: float, ica_vel: float) -> Tuple[float, str]:
        lr = round(mca_vel / max(ica_vel, 5.0), 2)

        if mca_vel >= 200.0 or lr >= 6.0:
            interp = f"SEVERE ANGIOGRAPHIC VASOSPASM (MCA MFV {mca_vel:.0f} cm/s >= 200, Lindegaard Ratio {lr:.2f} >= 6.0) -> Critical luminal constriction; high risk of DCI infarction."
        elif (140.0 <= mca_vel < 200.0) and lr >= 3.0:
            interp = f"MODERATE VASOSPASM (MCA MFV {mca_vel:.0f} cm/s, Lindegaard Ratio {lr:.2f} between 3.0-5.9)."
        elif (120.0 <= mca_vel < 140.0) and lr >= 3.0:
            interp = f"MILD VASOSPASM (MCA MFV {mca_vel:.0f} cm/s, Lindegaard Ratio {lr:.2f} between 3.0-5.9)."
        elif mca_vel >= 120.0 and lr < 3.0:
            interp = f"HYPEREMIA / HIGH CARDIAC OUTPUT (MCA MFV {mca_vel:.0f} cm/s elevated, but Lindegaard Ratio {lr:.2f} < 3.0 rules out true vasospasm)."
        else:
            interp = f"NORMAL CEREBRAL HEMODYNAMICS (MCA MFV {mca_vel:.0f} cm/s < 120, Lindegaard Ratio {lr:.2f} < 3.0)."

        return lr, interp

    def generate_management_protocols(self, d: SAHPatientTelemetry, is_severe_spasm: bool) -> Tuple[List[str], List[str], List[str]]:
        nimodipine_orders = []
        dci_plan = []
        sentinels = []

        # 1. Enteral Nimodipine Protocol
        nimodipine_orders.append("1. ENTERAL NIMODIPINE ORDER: Administer Nimodipine 60 mg orally or via nasogastric/orogastric tube every 4 hours for exactly 21 consecutive days.")
        nimodipine_orders.append("   • If transient hypotension occurs, reduce dosing interval to 30 mg every 2 hours; do NOT discontinue.")

        # 2. Safety Sentinel: Black Box Prohibition on IV Nimodipine
        if d.active_nimodipine_route == "Intravenous":
            sentinels.append("🚨 FATAL BLACK BOX CONTRAINDICATION: Intravenous Nimodipine administration causes profound, irreversible hypotension and fatal cardiovascular arrest. Nimodipine MUST STRICTLY BE GIVEN ENTERALLY (PO/NG). STAT CEASE IV INFUSION!")

        # 3. Delayed Cerebral Ischemia (DCI) Hemodynamics
        dci_plan.append("1. STRICT EUVOLEMIA: Maintain normovolemia using isotonic crystalloids (Plasmalyte / 0.9% Normal Saline). Avoid prophylactic hypervolemia (Triple-H is obsolete; causes pulmonary edema and hyponatremia).")

        if is_severe_spasm or d.day_post_ictus in range(4, 15):
            if d.aneurysm_secured:
                dci_plan.append("2. INDUCED HYPERTENSION (Aneurysm Secured):")
                dci_plan.append(f"   • Titrate IV Norepinephrine or Phenylephrine to elevate blood pressure by 20-30% above baseline.")
                dci_plan.append(f"   • Hemodynamic Target: SBP 160 - 180 mmHg or MAP > 100 - 110 mmHg (Current MAP {d.current_map_mmhg:.0f} mmHg).")
                dci_plan.append("3. ENDOVASCULAR RESCUE TRIGGER: If neurological deficits or severe TCD vasospasm persist despite induced hypertension, immediately transfer for intra-arterial Nicardipine/Verapamil infusion or transluminal balloon angioplasty.")
            else:
                dci_plan.append("2. ⚠️ UNSECURED ANEURYSM: Maintain SBP < 140 - 160 mmHg until aneurysm is coiled or clipped to prevent catastrophic rebleeding.")

        sentinels.append("HYPONATREMIA / CSW SENTINEL: Cerebral Salt Wasting (CSW) and SIADH are frequent in aSAH. Never fluid-restrict in SAH. Treat hyponatremia (Na < 135 mEq/L) with hypertonic 3% saline infusions.")

        return nimodipine_orders, dci_plan, sentinels

    def evaluate_case(self, data: SAHPatientTelemetry) -> SAHEvaluationReport:
        hh_grade, hh_desc = self.calculate_hunt_hess_grade(data)
        wfns_grade = self.calculate_wfns_grade(data.glasgow_coma_scale, data.motor_deficit_present)
        mf_grade, mf_desc = self.calculate_modified_fisher_scale(data)
        lr_val, lr_desc = self.evaluate_tcd_lindegaard(data.tcd_mca_mean_flow_velocity_cm_s, data.tcd_ica_extracranial_velocity_cm_s)
        is_severe = "SEVERE" in lr_desc
        nimo_orders, dci_plan, sentinels = self.generate_management_protocols(data, is_severe)

        directives = []
        directives.append(f"HUNT-HESS: Grade {hh_grade} (WFNS Grade {wfns_grade}).")
        directives.append(f"MODIFIED FISHER: Grade {mf_grade} ({mf_desc}).")
        directives.append(f"TCD VASOSPASM: {lr_desc}.")

        return SAHEvaluationReport(
            patient_id=data.patient_id,
            hunt_hess_grade=hh_grade,
            hunt_hess_description=hh_desc,
            wfns_grade=wfns_grade,
            modified_fisher_grade=mf_grade,
            modified_fisher_vasospasm_risk=mf_desc,
            tcd_lindegaard_ratio=lr_val,
            tcd_vasospasm_interpretation=lr_desc,
            nimodipine_order_protocol=nimo_orders,
            dci_hemodynamic_management=dci_plan,
            safety_sentinels=sentinels,
            clinical_ncs_aha_directive=" ".join(directives)
        )

# Example Execution & Verification
if __name__ == "__main__":
    engine = SubarachnoidHemorrhageDecisionEngine()

    print("=" * 80)
    print("OpenPHR Clinical Neurocritical Care Subarachnoid Hemorrhage & TCD Engine")
    print("=" * 80)

    # Test Case 1: 54-year-old female on Day 7 post-aneurysm coiling presenting with severe headache,
    # GCS 14, CN III palsy (Hunt-Hess Grade 2, WFNS Grade 2).
    # CT: Thick cisternal blood >= 1mm + Bilateral IVH (Modified Fisher Grade 4 - 40% DCI risk!).
    # TCD: MCA velocity 215 cm/s, ICA 32 cm/s -> Lindegaard Ratio: 6.72 (Severe Vasospasm!).
    # Triage: Enteral Nimodipine 60mg q4h x 21d + Norepinephrine Induced Hypertension (MAP > 100 mmHg)!
    sah1 = SAHPatientTelemetry(
        patient_id="NEURO-SAH-7701",
        age_years=54.0,
        day_post_ictus=7,
        glasgow_coma_scale=14,
        headache_severity="Severe",
        nuchal_rigidity_present=True,
        cranial_nerve_palsy=True,
        motor_deficit_present=False,
        ct_thick_cisternal_clot_ge_1mm=True,
        ct_bilateral_intraventricular_hemorrhage=True,
        tcd_mca_mean_flow_velocity_cm_s=215.0,
        tcd_ica_extracranial_velocity_cm_s=32.0,
        aneurysm_secured=True,
        current_sbp_mmhg=135.0,
        current_map_mmhg=88.0,
        is_euvolemic=True,
        active_nimodipine_route="Enteral / Oral"
    )

    rep1 = engine.evaluate_case(sah1)

    print(f"\n[Patient {rep1.patient_id} - Neuro-ICU SAH Assessment]")
    print(f"Clinical Severity: Hunt & Hess Grade {rep1.hunt_hess_grade} ({rep1.hunt_hess_description})")
    print(f"WFNS Scale: Grade {rep1.wfns_grade}")
    print(f"Radiologic Vasospasm Risk: Modified Fisher Grade {rep1.modified_fisher_grade} ({rep1.modified_fisher_vasospasm_risk})")
    print(f"\nTCD Hemodynamics (Lindegaard Ratio: {rep1.tcd_lindegaard_ratio:.2f}):\n  {rep1.tcd_vasospasm_interpretation}")
    print("\nNimodipine Neuroprotection Protocol:")
    for n in rep1.nimodipine_order_protocol:
        print(f"  {n}")
    print("\nDelayed Cerebral Ischemia (DCI) Hemodynamic Protocols:")
    for dci in rep1.dci_hemodynamic_management:
        print(f"  {dci}")
    if rep1.safety_sentinels:
        print("\nSafety Sentinels:")
        for s in rep1.safety_sentinels:
            print(f"  🚨 {s}")
    print(f"\nNCS / AHA Consensus Directive:\n{rep1.clinical_ncs_aha_directive}")