Pitfalls in neuroimaging of headache

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Pitfalls in neuroimaging of headache

A 74-year-old Caucasian male originally presented to the headache clinic with 1-year history of right sided headache affecting the frontotemporooccipital region. It was daily persistent headache with a pain intensity of 4/10. The nature of pain varied between dull ache with short lived shooting in the right retro orbital area once or twice a week with occasional photophobia. There was no nausea or visual dysfunction. Postural changes or valsalva did not aggravate the headache. The headache failed to settle with analgesics.

The most likely diagnosis of this presentation is

  • Sinusitis
  • Headache
  • Migraine
  • Meningioma

Introduction

Headache is a common symptom, with a lifetime prevalence of over 90% of the general population in the clinical practice.1 Overall 1-year prevalence of headache in European adults is 51%.2   It accounts for 4.4% of consultations in primary care and 30% of neurology outpatient consultations. Neuroimaging is indicated in select patients with headache. We report a unique case where the initial CT scan failed to identify a potentially treatable cause for headache.

Medical History

The patient had previous history of migraine in his teens which varied in frequency and severity. The last episode of migraine was experienced 10 years ago. There was a positive family history of migraine with both mother and sister undergoing treatment presently.The patient had significant medical history of ischemic heart disease, diabetes mellitus and COPD.

Examination

There was no clinical abnormality on routine head and neck examination. Detailed neurological examination failed to reveal any abnormality. A non-contrast CT scan of the brain was carried out to rule out intracranial pathology.

Management

The differential diagnosis included hemicrania continua or chronic migraine. A trial of indomethacin with a starting dose of 25mg was given and the dose was titrated slowly upward weekly depending on his tolerability and his INR. The CT scan showed age related cerebral atrophy with no intracranial abnormality.

The response to the standard prophylactic and therapeutic treatment for migraine was suboptimal and variable. Six months later, the patient presented with new symptoms of right sided odynophagia and dysphagia which were confirmed to be due to the advanced oropharyngeal carcinoma with cervical metastasis. A staging contrast enhanced CT scan of head, neck, and chest revealed a 4 cm enhancing mass in the right middle cranial fossa in keeping with a sphenoidal ridge meningioma. There was mild surrounding edema but no midline shift was noted.

The patient underwent surgery with postoperative radiotherapy for his oropharyngeal cancer. The patient will remain under serial radiological (MRI scan) surveillance for his meningioma. The headache is thought to be secondary to meningioma and pain is managed with standard analgesics.

Discussion

Headache is one of the most common presenting features in general practice, neurology, or otolaryngology clinics. Headaches are of two types i.e. Primary & Secondary. Primary headaches are not associated with underlying pathology. Migraine, cluster headache, and tension headache are grouped as primary headaches. Secondary headache is due to underlying pathology such as infections, vascular causes, trauma, and neoplasma.3 The etiology and diagnosis of most headaches can be elucidated by careful history, examination and radiological investigation. If neurological symptoms are present then a brain CT or MRI should be done as a primary investigation. 4   Perhaps contrast enhanced CT is a better option than plain CT scan of brain.

In our case, the non-contrast CT failed to diagnose meningioma, thought to be the underlying cause for his headache. Headache may be noticed in 60% of patients with intracranial tumour but it may not be the presenting feature. Schankin et al. 5 published data on 58 cases of meningioma and 40% of meningioma patients had associated headache features. Of these, the pain was migraine-like in 22% and tension-type-headache- (TTH-) like in 57%. There is a consensus that mass lesion produces headache either by inducing pressure on pain sensitive dura or arachnoid membranes or by increase in ICP but robust evidence is lacking. Moreover the literature suggests that patients with meningioma present with isolated headache without clinical signs of raised intracranial pressure. 6

In our case there were no neurological symptoms to raise the suspicion of intracranial neoplasm. Therefore, he was not given any contrast during neuroimaging. The exact cause of his headache remained unknown. The meningioma was diagnosed on a repeat CT scan with contrast enhancement and is a potentially treatable cause of headache.

Learning

The neuroimaging guidelines for investigation of headache do not recommend contrast enhancement as routine. However, this case highlights the inadequacy of the non-contrast CT

scan to diagnose meningioma. In a patient with persistent headache where other causes are excluded and a CT scan is to be requested, the clinician should be aware of the limitations in the sensitivity of an un-enhanced head CT, and where concerning symptoms persist, an alternative imaging modality such as MRI scan should be considered.

Reference

  1. B. K. Rasmussen, R. Jensen,M. Schroll, and J. Olesen, “Epidemiology of headache in a general population—a prevalence study,”Journal of Clinical Epidemiology, vol. 44, no. 11, pp. 1147–1157,1991.
  2. L. J. Stovner, J. A. Zwart, K. Hagen, G. M. Terwindt, and J. Pascual, “Epidemiology of headache in Europe,” European Journal of Neurology, vol. 13, no. 4, pp. 333–345, 2006.
  3. British Association for the Study of Headache, Guidelines for All Healthcare Professionals in the Diagnosis and Management of Headache, 3rd edition, 2010,  217.174.249.183/upload/NS BASH/2010 BASH Guidelines.pdf.
  4. Scottish Intercollegiate Guidelines Network, “Diagnosis and management of headache in adults. Guideline no. 107,” November 2008.
  5. C. J. Schankin, M. Krumbholz, P. Sostak, M. Reinisch, R. Goldbrunner, and A. Straube, “Headache in patients with a meningioma correlates with a bone-invasive growth pattern but not with cytokine expression,” Cephalalgia, vol. 30, no. 4, pp. 413–424, 2010.
  6. M. Levin, “Resident and fellow section,” Headache, vol. 49, no. 4, pp. 627–630, 2009.

 

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