This calculator is for general information and education. It is not medical advice and does not replace the judgment of a doctor, nurse or pharmacist who knows the full clinical picture.
A subarachnoid hemorrhage from a ruptured aneurysm is one of the most serious emergencies in neurology. Its outcome depends largely on the patient’s condition on arrival. In 1968 the neurosurgeons William Hunt and Robert Hess proposed a five-grade clinical scale to estimate surgical risk, and the Hunt and Hess scale is still used every day, with the WFNS grade, to describe how severe the bleed is.
The grades
| Grade | Clinical picture |
|---|---|
| I | no symptoms, or mild headache and slight neck stiffness |
| II | moderate to severe headache, neck stiffness, no deficit other than a cranial nerve palsy |
| III | drowsiness, confusion or a mild focal deficit |
| IV | stupor, moderate to severe hemiparesis, possibly early decerebrate rigidity |
| V | deep coma, decerebrate rigidity, moribund appearance |
The original paper added one grade for serious systemic disease, such as hypertension, diabetes, severe atherosclerosis or chronic lung disease, or for severe vasospasm on angiography. The calculator applies that rule and caps the result at V.
Example
A patient with a severe headache, a stiff neck and no deficit is grade II. If the same patient has long-standing poorly controlled hypertension, the grade becomes III.
Interpretation
Grades I to III are usually called good grades and IV to V poor grades. In the original series, surgical mortality rose from about 11% in grade I to 26% in grade II, 37% in grade III and 71% in grade IV, and nearly every grade V patient died. Modern care has improved these figures a great deal, so use them as history rather than as a prognosis.
Hunt and Hess or WFNS?
The Hunt and Hess scale uses words such as drowsy or stupor, which different observers interpret differently. The WFNS grade, built on the Glasgow Coma Scale and the presence of a motor deficit, is more reproducible, and many centers record both. Imaging scales such as the modified Fisher grade add the risk of vasospasm from the amount of blood on the CT scan.
Limits
Grade the patient after resuscitation and treatment of hydrocephalus or seizures when possible, since the grade can improve quickly. The scale guides prognosis and communication; treatment decisions belong to the neurovascular team.