What Does a Normal MRI Mean for Hemicrania Continua?

Receiving normal MRI results is reassuring—it lowers the concern that a major structural problem, like a large tumor, is causing your head pain ^[1]. However, a normal scan does not mean your pain is imaginary, and it does not automatically explain why your symptoms persist. Because hemicrania continua is primarily diagnosed by your specific symptom pattern and how completely you respond to medication, a clear scan is just one piece of the puzzle. If you are still experiencing symptoms, the next steps usually involve a detailed review of your symptom pattern, an evaluation of your medication response, and consideration of whether any targeted follow-up tests are needed.

Understanding Your Normal MRI

Hemicrania continua is typically a primary headache disorder, meaning the pain is caused by how the brain and its pain pathways function rather than a visible physical defect ^[2]. Because of this, it is entirely expected for a person with primary hemicrania continua to have a completely normal routine brain scan ^[1].

However, doctors order an MRI to rule out a secondary headache disorder—head pain that mimics hemicrania continua but is actually caused by an underlying structural or vascular (blood vessel) issue ^[1]. While a standard, routine brain MRI is excellent for ruling out large abnormalities, it may not exclude every rare problem ^[3]. Certain very specific issues—such as abnormalities in the blood vessels, the neck, or the pituitary gland (a small hormone-producing gland at the base of the brain)—might not be fully visible on a routine scan without specialized imaging techniques ^[3][4].

What Happens Next?

If your MRI is normal but your symptoms persist, your care team will likely reassess your clinical pattern and your medication response.

Reassessing Your Clinical Pattern

Your doctor will review your symptom history to see if it strictly matches the diagnostic criteria for hemicrania continua. The condition requires a strictly one-sided, continuous background ache present for at least three months, with superimposed spikes of more severe pain ^[2]. During these severe flares, you should also experience autonomic symptoms on the same side as the pain, such as eye tearing, nasal congestion, a drooping eyelid, or a sense of restlessness ^[2][5].

If your pain goes away completely between attacks, you might have a different type of Trigeminal Autonomic Cephalalgia (TAC), such as paroxysmal hemicrania, which features shorter, distinct attacks ^[6]. Only a clinician can distinguish these based on attack duration and frequency.

Reviewing Your Medication Response

The defining feature of hemicrania continua is an “absolute” or complete response to an adequate, therapeutic dose of indomethacin (a prescription nonsteroidal anti-inflammatory drug) ^[7]. If you still have symptoms, your doctor will evaluate your medication trial:

• Was the dose high enough? Trials require reaching a specific therapeutic dose; however, never increase your dose on your own due to severe risks like gastrointestinal bleeding, kidney injury, and blood pressure spikes ^[8][9].
• Was it taken consistently? Symptoms often return as the drug wears off; missing a dose can cause your headache to recur, meaning the trial requires strict adherence ^[2].
• Was the relief complete? A partial improvement is not enough to confirm hemicrania continua ^[10].

If indomethacin is unsafe for you, intolerable, or does not provide complete relief, your doctor may evaluate you for other headache disorders like migraine ^[10], or discuss alternative treatments if hemicrania continua is still suspected ^[11]. Interestingly, even if indomethacin completely stops the pain, it does not guarantee the headache is primary, as some secondary causes also respond to it ^[1].

When Are Further Tests Needed?

Additional imaging is not automatically required just because your symptoms continue. Depending on your neurological exam, symptom red flags, and what your original MRI covered, your doctor might recommend targeted investigations:

• Dedicated MRI Views: If your initial scan did not include them, imaging specifically focused on the pituitary gland or the cavernous sinus (a space behind the eye housing nerves and blood vessels) might be considered if your doctor suspects issues there ^[3][12].
• Vascular Imaging: If you have certain nerve signs, such as a drooping eyelid or unequal pupils, an MR Angiography (MRA) might be used to check the blood vessels in your neck and brain for issues like an artery tear ^[13][4].
• Spinal Imaging: Rarely, if your symptoms heavily suggest a neck origin, a cervical spine MRI may be considered ^[14].

🚨 Emergency Symptoms: When to Seek Immediate Care

A normal initial MRI does not mean you should ignore new, severe, or evolving symptoms. Call emergency services or go to the nearest emergency department immediately if you develop any of the following warning signs, as they could indicate a life-threatening or vision-threatening emergency (such as a stroke, aneurysm, or acute angle-closure glaucoma) ^[12][13][15]:

• A sudden, maximal “thunderclap” headache
• Severe eye pain accompanied by a red eye, blurred vision, halos, and nausea
• Diplopia (new double vision) or any sudden vision loss
• Ptosis (a newly drooping eyelid) with noticeably unequal pupil sizes
• New numbness, weakness, or paralysis in your face, arm, or leg
• Confusion, fainting, seizures, or fever with a stiff neck