SNNOOP10: Headache Red Flags Every Physiotherapist Should Screen

Q: What does SNNOOP10 stand for?

SNNOOP10 is a mnemonic for the ten red-flag categories that suggest a secondary cause of headache: Systemic symptoms, Neurological signs, sudden Onset, Onset after 50, Pattern change, Positional, Precipitated by Valsalva, Progressive, Pregnancy, Painful eye, Post-traumatic, immune Pathology, and Painkiller overuse.

Q: Should physiotherapists screen for headache red flags?

Yes. Physiotherapists are often the first or only clinician seeing a headache patient. Running SNNOOP10 on every headache presentation is a minimum standard of safe practice and is required before applying any cervical manual therapy.

Q: What headache symptoms require immediate medical referral?

Thunderclap onset, focal neurological signs, altered consciousness, papilloedema, fever with neck stiffness, worsening post-traumatic headache, and rapidly progressive headache all require same-day medical review or emergency referral.

Most headaches presenting to physiotherapy are primary (migraine, tension-type, cervicogenic). A small but critical minority are secondary - symptoms of vascular, infectious, neoplastic, or structural pathology. SNNOOP10, derived from ICHD-3 criteria, gives you a structured way to screen for these before any manual or exercise treatment.

What SNNOOP10 stands for

Each letter represents a category of red-flag features. A positive answer in any category does not by itself confirm secondary pathology, but should prompt referral, imaging, or escalation depending on severity and clinical context.

S - Systemic symptoms or systemic disease (fever, weight loss, immunosuppression, cancer history).
N - Neurological signs or symptoms (focal deficits, altered consciousness, seizures, papilloedema).
N - Sudden onset (thunderclap headache - peak intensity in <1 minute).
O - Onset after age 50.
O - Pattern change or recent onset of new headache.
P - Positional headache (worse lying down or standing - suggests CSF pressure abnormalities).
P - Precipitated by Valsalva (cough, sneeze, exertion).
P - Progressive headache and atypical presentations.
P - Pregnancy or post-partum.
P - Painful eye with autonomic features (cluster, intracranial pathology).
P - Post-traumatic onset.
P - Pathology of the immune system (HIV, immunosuppression).
P - Painkiller overuse or new drug at onset (medication-overuse headache).

How to use SNNOOP10 in practice

Run SNNOOP10 as part of every headache subjective examination. Document each category as positive, negative, or not assessed. A single high-severity positive (e.g., thunderclap, focal neurology, papilloedema) warrants immediate medical referral. Multiple lower-severity positives also lower your threshold for onward referral.

SNNOOP10 does not replace clinical judgement - it standardises the floor. Use it together with cranial nerve screening, blood pressure measurement, and (where indicated) cervical artery dysfunction screening before any cervical manual therapy.

When to refer immediately

Thunderclap headache, focal neurological signs, altered consciousness, papilloedema, fever with neck stiffness, post-traumatic headache with worsening symptoms, or any rapidly progressive headache require same-day medical review or emergency referral. When in doubt, refer.

Key takeaways

SNNOOP10 is the ICHD-3 endorsed red-flag screen for secondary headache.
Run it on every headache patient; document each category.
A single high-severity positive warrants immediate referral.
Combine SNNOOP10 with cranial nerve and (where indicated) cervical artery dysfunction screening.
When in doubt, refer - primary care or emergency depending on severity.

Frequently asked questions

What does SNNOOP10 stand for?

SNNOOP10 is a mnemonic for the ten red-flag categories that suggest a secondary cause of headache: Systemic symptoms, Neurological signs, sudden Onset, Onset after 50, Pattern change, Positional, Precipitated by Valsalva, Progressive, Pregnancy, Painful eye, Post-traumatic, immune Pathology, and Painkiller overuse.

Should physiotherapists screen for headache red flags?

Yes. Physiotherapists are often the first or only clinician seeing a headache patient. Running SNNOOP10 on every headache presentation is a minimum standard of safe practice and is required before applying any cervical manual therapy.

What headache symptoms require immediate medical referral?

Thunderclap onset, focal neurological signs, altered consciousness, papilloedema, fever with neck stiffness, worsening post-traumatic headache, and rapidly progressive headache all require same-day medical review or emergency referral.