Headaches and Neurological Changes: When to Evaluate

NHS opens its headache page with the general truth: most headaches go away on their own and are not a sign of anything serious. Then it lists the exceptions.

Call 999 in the UK, or 911 in the United States, and go to an emergency department for a headache that comes with any of these:

• It started suddenly and is extremely painful.
• A seizure.
• Numbness or weakness in the body or face.
• Difficulty speaking, balancing, walking, or remembering things.
• Drowsiness or confusion.
• Loss of vision.
• A rash that does not fade when a glass is rolled over it.
• A very high temperature, a stiff neck, or bright light becoming unbearable.
• A head injury within the last 3 months.

NHS adds one instruction people routinely get wrong: do not drive yourself. Ask someone else to drive, or call for an ambulance. Bring any medicines with you.

A second NHS list sits below that one. These are reasons to ask for an urgent appointment or call a nurse advice line rather than go straight to an emergency department:

• A headache with vision or eye problems.
• A headache triggered or made worse by coughing, sneezing, bending down or exercising.
• A headache with vomiting.
• In a child, a headache that is getting worse or waking them at night.
• A headache with jaw pain when eating, or a sore or tender scalp.

The trigger list is the one worth memorizing. Coughing, sneezing, bending and straining all raise pressure inside the skull briefly. A headache that answers to that is describing something about pressure, not about stress.

Two features carry the weight in both lists: how the headache started, and what came with it.

A sudden, extremely painful onset is one pattern. A headache that is new, different from a person's usual headaches, and changing is the other. Neither is a pain score. Someone can describe a moderate headache and still be describing an emergency, and someone can be in agony from a migraine that needs no scan.

That is why the useful thing to bring to an appointment is a timeline. When it started. Whether it was sudden. What makes it worse. What is new alongside it.

NCI's summary on adult central nervous system tumors approaches this from the other end — not which headaches to worry about, but what these tumors do.

Its general list is short:

• Headaches.
• Seizures.
• Visual changes.
• Gastrointestinal symptoms such as loss of appetite, nausea and vomiting.
• Changes in personality, mood, mental capacity and concentration.

NCI also frames how those signs arise: the clinical presentation of brain tumors is best understood by relating signs and symptoms to anatomy. Where the tumor sits determines what it disturbs.

This is the statistic that reframes the whole question.

Seizures are a presenting symptom in approximately 20% of people with supratentorial brain tumors — tumors above the tentorium, the sheet of tissue separating the cerebrum from the cerebellum. In slow-growing tumors, NCI states that seizures may precede the clinical diagnosis by months to years.

Across all people with brain tumors, 70% of those with primary parenchymal tumors and 40% of those with metastatic brain tumors develop seizures at some point during their illness.

A first seizure in an adult is on the emergency list above for that reason.

NCI's section on brain metastases separates symptoms the person reports from changes other people see.

Patients describe headaches, weakness, seizures, sensory problems and difficulty walking. Family members and friends notice lethargy, emotional lability — rapid swings in mood — and personality change.

That split matters when a symptom is described by a partner rather than the patient. It is not a secondhand account of the same thing. It is a category of finding that people frequently cannot report about themselves.

If imaging is arranged, NCI describes the two tests as complementary rather than interchangeable.

CT is fast, which matters for someone clinically unstable. It is better at detecting calcifications, skull lesions and hyperacute bleeding — blood less than 24 hours old.

MRI has superior soft-tissue resolution. It picks up lesions that blend into surrounding tissue on CT, shows contrast enhancement and swelling, and detects all phases of bleeding except the hyperacute. NCI calls high-quality MRI the study of choice for spinal cord lesions.

NCI also notes what any scan has to sort out. Brain tumors, whether primary or metastatic, must be told apart from other things taking up space inside the skull — abscesses, arteriovenous malformations and infarctions among them.

If a tumor is found, some of the symptoms come from the swelling around it rather than the tumor itself.

NCI names three drugs used against that swelling: dexamethasone, mannitol and furosemide. It also states that anticonvulsants are mandatory for patients who have had seizures. Those two facts explain why steroids and seizure medicines often start before any decision about surgery or radiation is made.

None of this is the likely answer for most headaches. NHS lists the common causes: a cold or flu, stress, too much alcohol, bad posture, eyesight problems, skipping meals, dehydration, taking too many painkillers, and hormonal changes around periods or menopause.

It also suggests a headache diary as a way to work out triggers. That is a reasonable first step for recurring headaches with none of the patterns above.

For the broader principle, see a symptom is not a diagnosis.

• NCI PDQ — Adult Central Nervous System Tumors Treatment (Health Professional Version)
• NHS — Headaches