Some Headache Disorders other than migraine
Tension Type Headaches
Tension type headaches are common, but are frequently confused with migraine. They are featureless, mild headaches that do not affect activity. People do not need to take medication and medication is not effective. They are not necessarily caused by stress, despite the name. People can describe a band or pressure type sensation around the head.
Trigeminal autonomic cephalalgias (TACs)
These are a group of primary headache disorders that are much less commonly seen compared to migraine. They can be seen individually but can co-exist with migraine. They are caused by activation of the trigeminal nerve, and the treatments overlap with migraine but also include medications not usually given in migraine, at least not first line.
Cluster headache – is a severe unilateral headache lasting around 15 minutes – 90 minutes. It is always in V1 (the top third of the face – the forehead and eye) and is side-locked. There is associated tearing and nasal congestion. There is associated agitation and patients generally pace around (rather than lying in bed). In some patients it will occur in “clusters” for a few months then improve, however it can become chronic. It often occurs at the same time of day and can be very difficult to manage.
Sudden unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA)
These are rare, and similar to cluster headache in where they occur – always V1 distribution and usually unilateral, however they are very brief – lasting seconds usually to minutes at a maximum. They can occur up to hundreds of times per day however, and can be very debilitating.
Hemicrania continua and Paroxysmal hemicrania
There is pain on one side of the head only, but it is continuous. It can respond well to a non steroidal anti-inflammatory medication, indomethacin. Paroxysmal hemicrania is similar in character and response to indomethacin, but occurs in episodes of about 30 minutes, throughout the day. Both conditions can be very difficult to treat.
Idiopathic intracranial hypertension (previously called benign intracranial hypertension)
This is a disorder of CSF production, the cause of which is not fully understood. It affects young women mostly, and can present with headache difficult to distinguish from migraine, as well as pulsatile tinnitus (a sensation of the heart beat or “whooshing” in the ears) and visual changes. It is affected by weight change particularly rapid, and needs to be monitored closely in pregnancy. It is an important differential in all women with headache, and fundscopy looking for papilloedema (swelling of the optic disc at the back of the eye) should be part of a routine examination. Imaging will generally be negative (there is no hydrocephalus, but there can be some non-specific signs which are generally unhelpful) – lumbar puncture with opening CSF pressure measurement is really important to make the diagnosis. Treatment is generally with Acetazolamide (Diamox) first line, which reduces production of CSF, and therefore reduces the intracranial pressure. Sometimes topiramate or frusemide are used as these have a diuretic effect that reduces CSF pressure as well, but less effectively. In severe cases, sometimes shunts have to be inserted especially if there is a threat to vision from too much pressure on the optic nerves.
Cerebral venous sinus thrombosis
This can be difficult to distinguish from migraine in that it is a severe, throbbing headache usually, and can be associated with nausea and vomiting as well as light sensitivity. It should be considered in a patient with no known history of migraine, particularly if the headache has been present for several days. It will not be evident on a non-contrast CT brain, and a CT venogram or MR venogram is ideally the investigation of choice. The venous clot will produce raised intracranial pressure, causing papilloedema, and it can sometimes present similarly to idiopathic intracranial hypertension, although generally with a more sudden onset. Anticoagulation (blood thinners) is necessary to prevent the clot extending and eventually the body breaks the clot down itself. Investigation into underlying causes of abnormal clotting or other clotting risk factors needs to be undertaken, and this will determine how long a person has to take anticoagulation for. Fortunately cerebral venous sinus thrombosis is rare, but it is one of the migraine mimics not to be missed.