Hunt and Hess scale: the five grades and how serious systemic disease moves the grade
The Hunt and Hess scale grades a person with subarachnoid hemorrhage from an aneurysm on a scale of 1 to 5, from no symptoms or a mild headache (grade 1) to deep coma (grade 5). Serious systemic disease moves the grade up by one, but never past 5.
Not a medical device. Not a diagnosis or dosing recommendation.
What is the Hunt and Hess scale?
The scale comes from William Hunt and Robert Hess, who described it in the Journal of Neurosurgery in 1968, in a paper on surgical risk and the timing of aneurysm repair. Each grade has a short clinical description. The paper also places a patient with serious systemic disease in the next less favorable grade.
Magent's calculator takes a grade from 1 to 5 that you assign, applies that one-step move when you mark serious systemic disease, and returns the grade with its 1968 wording. It doesn't examine the patient. It isn't the later Hunt and Kosnik version from 1974 with grade 0 and grade 1a, and it isn't the WFNS scale.
This page explains how the grade is assigned. It doesn't say what a grade means for a particular person.
The Hunt and Hess rule
grade = the grade you assign (1–5)
if serious systemic disease: grade + 1, but no higher than 5Exact expression the calculator uses:
assigned_grade = min(5, grade + 1) if serious_systemic_disease, else grade; Hunt and Hess 1968 grades 1-5The five grades
| Input grade | 1968 description |
|---|---|
| 1 | Asymptomatic, or minimal headache and slight nuchal rigidity |
| 2 | Moderate to severe headache, nuchal rigidity, no neurologic deficit other than cranial nerve palsy |
| 3 | Drowsiness, confusion, or mild focal deficit |
| 4 | Stupor, moderate to severe hemiparesis, possibly early decerebrate rigidity and vegetative disturbances |
| 5 | Deep coma, decerebrate rigidity, moribund appearance |
How the grade is assigned
- Pick the grade. The person using the calculator picks 1 to 5 from the descriptions above.
- Mark serious systemic disease. True or false. The calculator's examples of serious systemic disease are hypertension, diabetes, severe arteriosclerosis, chronic pulmonary disease and severe vasospasm seen on angiography, as you assign them.
- Apply the step. If serious systemic disease is true, the grade goes up by one, but no higher than 5.
Inputs come from the user
Both inputs are set by the person using the calculator. Magent's calculator doesn't examine the patient or decide whether systemic disease is serious. It returns the grade you entered, whether the step was applied, the final grade, the maximum of 5 and the 1968 description for the final grade.
Worked examples
These use Magent's own expected values for the calculator.
Example 1: grade 2, no serious systemic disease
- No step applies.
- Grade: 2, "Moderate to severe headache, nuchal rigidity, no neurologic deficit other than cranial nerve palsy".
Example 2: grade 2, serious systemic disease
- Step: 2 + 1 = 3.
- Grade: min(5, 3) = 3, "Drowsiness, confusion, or mild focal deficit".
Example 3: grade 5, serious systemic disease
- Step: 5 + 1 = 6.
- Grade: min(5, 6) = 5. The grade can't go past 5.
Example 4: grades 1, 3 and 4, no serious systemic disease
- Each grade comes back unchanged: 1, 3 and 4.
History of the scale
The scale comes from Hunt WE and Hess RM, Surgical risk as related to time of intervention in the repair of intracranial aneurysms, Journal of Neurosurgery, 1968 (volume 28, issue 1, pages 14–20).
When it's used
The 1968 paper was about people with intracranial aneurysms. The grade is a description of the person's condition at the time it's assigned.
Where it's used
The grade comes from a bedside neurological assessment. The calculator doesn't need any lab values.
Who uses it
The person using the calculator assigns the grade and the systemic-disease flag. The calculator applies the step and returns the wording.
Limits of the calculation
- You assign the grade. The calculator doesn't examine the patient.
- It doesn't confirm a hemorrhage or say whether surgery is suitable.
- It's the 1968 version. It doesn't include the 1974 Hunt and Kosnik grade 0 or grade 1a.
- It isn't the WFNS scale.
- The systemic-disease step is one grade, capped at 5.
Clinical decisions belong to a qualified clinician who knows the patient.
How it differs from related calculators
- Ottawa SAH rule is a separate rule with its own items.
- ICH score is a separate points score for intracerebral hemorrhage.
- Glasgow Coma Scale scores eye, verbal and motor responses. Hunt and Hess uses short clinical descriptions instead.
Glossary
- Subarachnoid hemorrhage: bleeding into the space around the brain.
- Intracranial aneurysm: a bulge in an artery in the head.
- Nuchal rigidity: a stiff neck.
- Cranial nerve palsy: weakness of a nerve that comes directly from the brain.
- Hemiparesis: weakness on one side of the body.
- Decerebrate rigidity: a stiff, extended posture seen with severe brain injury.
- Vasospasm: narrowing of an artery.
Common mistakes
- Going past 5. The step stops at 5.
- Moving more than one grade. Serious systemic disease moves the grade by one.
- Using grade 0 or 1a. Those come from the 1974 Hunt and Kosnik version, not the 1968 scale.
- Mixing it up with WFNS. They're separate scales.
Source
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. DOI: 10.3171/jns.1968.28.1.0014. PMID: 5635959
Frequently asked questions
How do you work out a Hunt and Hess grade?
Pick the grade from 1 to 5 that matches the description. If serious systemic disease is present, move up one grade, but no higher than 5.
What is Hunt and Hess grade 3?
In the 1968 wording, grade 3 is "Drowsiness, confusion, or mild focal deficit".
What is the highest Hunt and Hess grade?
5: "Deep coma, decerebrate rigidity, moribund appearance".
What does serious systemic disease do to the grade?
It moves the grade up by one, capped at 5. Grade 2 becomes 3; grade 5 stays 5.
Is Hunt and Hess the same as the WFNS scale?
No. They're separate scales.