Managing post-traumatic headache: guidance for primary care

INTRODUCTION

Traumatic brain injury (TBI) is an acute pathological event related to penetration, accelerational, decelerational, or rotational forces. In primary care whiplash is very common and management is poor.¹

Estimates of post-TBI headache range from 30–90% but many people will not consult.² Other symptoms include physical, behavioural, emotional, and cognitive difficulties. Headache is the most important as it is common, often complicated by medication overuse headache (MOH), and can respond to treatment. Ninety-five per cent will reflect a recognised primary headache, most commonly migraine. Ninety per cent present within a week, resolving by 3–6 months, but headache can be problematic up to 5 years or longer.³

Previous history of a primary headache, female gender, and the presence of psychiatric disorders are risk factors for headache development. The area is complicated by:

• Lack of agreement on terminology. In primary care the terms head injury, concussion, and traumatic brain injury are often used interchangeably; similarly post-concussion syndrome and chronic traumatic encephalopathy are often conflated, although the neuropathology between these entities differ significantly.

• Limited understanding of underlying mechanisms. Early dysfunction results from axonal damage with an inflammatory reaction providing defensive responses and return to normality. However, this can persist with a complex cascade of pathophysiological changes that lead to impaired neurotransmission.

• No prognostic indicators. Coma and post-traumatic amnesia are best indicators of early structural damage but paradoxically do not necessarily equate to post-traumatic pain syndromes. Later problems occur more commonly with mild and moderate TBI.

• Limited evidence base. Epidemiological studies demonstrate a wide range of estimates and there is no good evidence base to direct treatment. A systematic review found one uncontrolled study showing amitriptyline helpful.⁴

• There is a significant population prevalence of similar symptoms in the absence of trauma. Symptoms of TBI occur commonly with a wide range of other problems and a coexisting post-traumatic stress disorder may give similar symptoms.

• Emotional and psychological responses may play a role, particularly when litigation is a factor, although the contribution of litigation to symptoms is unclear.