Hunt and Hess Classification: SAH Evaluation
Calculate the Hunt and Hess grade online. The essential clinical tool in neurosurgery to evaluate the severity of Subarachnoid Hemorrhage (SAH).
The Hunt and Hess Classification: Clinical Evaluation of Subarachnoid Hemorrhage (SAH)
Originally published in 1968 by neurosurgeons William Hunt and Robert Hess, the Hunt and Hess scale is a universally recognized clinical grading system in neurology, intensive care, and neurosurgery. It was designed to classify the clinical severity of patients suffering from a non-traumatic Subarachnoid Hemorrhage (SAH), the most frequent underlying cause of which is the rupture of an intracranial aneurysm. This standardized tool allows for clear communication among medical teams regarding the patient's acute neurological status.
Why use the Hunt and Hess score in clinical practice?
This classification is based exclusively on the patient's initial clinical examination at the time of admission (or just prior to surgery). Its use in the intensive care unit is crucial for two main clinical reasons:
- Survival Prognosis: There is a strong direct correlation between the initial clinical grade and the postoperative mortality and morbidity rate. A Grade I patient has an excellent prognosis (~70% survival), whereas a Grade V patient presents with catastrophic brain damage, associated with a mortality rate often exceeding 80-90%.
- Surgical Indication and Timing: Historically, this score helped determine the optimal timing for neurosurgical intervention (clipping or endovascular coiling of the aneurysm). Low grades (I to III) are often candidates for early surgery to prevent rebleeding, while high grades require prior intensive stabilization.
The Upgrade Rule (The Clinical Modifier)
A fundamental clinical point, often forgotten in rapid assessments, is the penalty rule established by the original authors: If the patient has a severe associated systemic disease (such as severe uncontrolled hypertension, decompensated diabetes, advanced atherosclerosis, severe COPD) or if a severe cerebral vasospasm is diagnosed via angiography, the score must be systematically increased by one Grade (e.g., from Grade II to Grade III). This accurately reflects the significantly increased surgical and vital risk.
Clinical Grades and Prognosis (Surgical Mortality)
| Grade | Clinical Presentation | Estimated Survival |
|---|---|---|
| I | Asymptomatique ou céphalées légères | 70% |
| II | Céphalées sévères, raideur de la nuque, pas de déficit | 60% |
| III | Somnolence, confusion, déficit focal léger | 50% |
| IV | Stupeur, hémiparésie, troubles végétatifs | 20% |
| V | Coma profond, posture de décérébration | 10% |
References:
1. Hunt WE, Hess RM. Surgical risk as related to time of intervention in the repair of intracranial aneurysms. J Neurosurg. 1968;28(1):14-20.
[PubMed - NIH]
2. Connolly ES Jr, et al. (AHA/ASA). Guidelines for the management of aneurysmal subarachnoid hemorrhage: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2012;43(6):1711-37.
[PubMed - AHA]
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