Abstract
Dear Sir Pain is undoubtedly the most common presenting symptom in any hospital and headache constitutes most of the pain presenting to the physician. As neuroscientists we are daily involved in the management of headache and our experience has prompted us to highlight the types of headache which should concern us. This is very important, particularly for our colleagues who are not neurospecialists but are daily confronted with headaches of various kinds.
Headaches are one of the most common symptoms that neurologists’ evaluate (1) and few of us are spared the experience of head pain (2). Although most are caused by primary disorders, the list of differential diagnoses is one of the longest in all of medicine with over 300 types and causes (1). Morbidity due to headache is a major problem. As many as 90% of individuals have at least one headache per year and severe disabling headache is reported to occur at least annually by 40% of individuals worldwide (2). Also, in emergency settings, approximately 3–5% of patients are found to have a serious underlying neurological disorder. As a very common complaint, common causes such as visual acuity problems, ear and paranasal sinus diseases, dental pathologies, upper cervical spine lesions, and febrile illnesses should be considered. At times, the causes may be non-physical. These include depression, hunger, tiredness, emotional and financial stress.
An accurate and detailed history as well as a comprehensive neurological examination is essential to screen for headache that will need to be further investigated. This is important, as delayed diagnosis may lead to delay in treatment, disability and/or death.
All headaches should be treated but should we then investigate all cases of headache? Several studies have shown that routine computed tomographic (CT) imaging of the brain in patients with headache, particularly in those with a normal neurological examination, is unlikely to discover significant intracranial disease (1). Also, the cost of detecting intracranial lesions in this patient population is high (2). In a consecutive sample of 350 patients with a chief complaint of headache regardless of the presence or absence of physical or neurological signs, referred for brain CT, only seven (2%) had clinically significant findings (3). In addition, in a series of 373 consecutive patients with chronic headache sent for both enhanced and unenhanced CT scans, four showed clinically significant lesions and only one treatable lesion. The cost per significant finding was $18 000, while it cost $74 243 to find one treatable cause (lesion) (3–5).
In the face of this dilemma and to avoid waste of scarce resources in a developing economy such as ours on one hand, and not to overlook serious underlying neurological disorders that CT scan could reveal on the other hand, the critical question is: which patients with headache need a brain CT scan? With the International Headache Society (IHS) diagnostic criteria for headache disorders (6), the separation of primary from symptomatic form of headaches has become more precise, but even so, without the help of neuroimaging, it cannot be confirmed that a patient presenting with migraine or tension-type headache does not have a serious intracranial lesion. The ‘red flag signs’ as described by the IHS can help to determine which patients to send for CT scanning. Fabbrini et al. however, believed that the general indications for CT or magnetic resonance imaging (MRI) in patients with headache are still a matter of dispute (7). As a screening procedure for intracranial pathology, CT and MRI appear to be equally sensitive. MRI is more expensive than CT scanning and less widely available. CT is therefore preferred in a developing economy.
The three most important factors that we have found useful in patients with non-traumatic headache presenting to our neurological and neurosurgical clinics are headache of more than a month's duration despite treatment, focal or lateralized headache rather than a generalized one, and headache associated with abnormal neurological findings. Using these criteria, 42% (55/131) of our patients had surgically correctable lesions on CT scan. Another 27% had gross lesions in the brain substance for which surgery is not indicated, such as multifocal cerebral metastasis.
CT brain scan with or without MRI is the standard for investigating the cause of a headache; however, in the tropics, where these neuroimaging facilities are not usually available and are very expensive, initial skull X-ray might be found useful as it may demonstrate features of chronically raised intracranial pressure (Table 1) which now makes CT/MRI mandatory. Table 1 shows the X-ray features prior to CT scan and the surgically correctable CT scan diagnosis. It is interesting to note that 32.7% of the patients with surgically treatable lesions on CT had a previously reported normal skull X-ray. Having a special clinic session for headaches may be important as well as a meta-analysis of studies on CT evaluation of headaches to design a scoring system with high sensitivity and specificity that will help us to decide which patients to send for neuroimaging studies.
X-ray and computed tomographic (CT) scan features of surgically correctable lesions in patients with headache
