Headache

Introduction

Headache is a common ailment that is often due to a combination of physical and psychological factors. The vast majority are benign and self-limiting and are managed by patients in the community.

Only a very small proportion of patients experiencing headache attend emergency departments (ED) for treatment. The challenges are to distinguish potentially life-threatening causes from the more benign, and to effectively manage the pain of headache.

Pathophysiology

The structures in the head capable of producing headache are limited. They include:

• Extracranial structures, including skin and mucosae, blood vessels, nerves, muscles and fascial planes.
• The main arteries at the base of the skull (as arteries branch they progressively lose the ability to produce painful stimuli).

• The great venous sinuses and their branches.
• The basal dura and dural arteries, but to a lesser extent than the other structures.

The bulk of the intracranial contents, including the parenchyma of the brain, the subarachnoid and pia mater and most of the dura mater, are incapable of producing painful stimuli.

The pathological processes that may cause headache are:

1. Tension — This usually refers to contraction of muscles of the head and/or neck, and is thought to be the major factor in the so-called ‘tension headache’.
2. Traction — Traction is caused by stretching of intracranial structures due to a mass effect, as with a tumor. Pain caused by this mechanism is characteristically constant, but may vary in severity.
3. Vascular processes — These include dilatation or distension of vascular structures, and usually result in pain that is throbbing in nature.
4. Inflammation — This may involve the dura at the base of the skull or the nerves or soft tissues of the head and neck. This mechanism is responsible for the initial pain of subarachnoid haemorrhage and meningitis, and for sinusitis.

Assessment

In the assessment of a patient with headache, history is of prime importance. Specific information should be sought about the timing of the headache (in terms of both overall duration and speed of onset), the site and quality of the pain, relieving factors, the presence of associated features such as nausea and vomiting, photophobia and alteration in mental state, medical and occupational history and drug use.

Intensity of the pain is important from the viewpoint of management but is not a reliable indicator of the nature of underlying pathology. This said, sudden, severe headache and chronic, unremitting or progressive headache are more likely to have a serious cause.

Physical examination should include temperature, pulse rate and blood pressure measurements, assessment of conscious state and neck stiffness and neurological examination, including funduscopy (where indicated). Abnormal physical signs are uncommon, but the presence of neurological findings makes a serious cause probable. In addition, a search should be made for sinus, ear, mouth and neck pathology and muscular or superficial temporal artery tenderness.

Headache Patterns

Some headaches have ‘classic’ clinical features: these are listed in Table X1 .

It must be remembered that, as with all diseases, there is a spectrum of presenting features and the absence of the classic features does not rule out a particular diagnosis. Every patient must be assessed on their merits and, if symptoms persists without reasonable explanation, further investigation should be undertaken.

Table X1

Investigation

For the vast majority of patients with headache no investigation is required. The investigation of suspected subarachnoid haemorrhage and meningitis is designated webpage. If tumor is suspected, the investigations of choice are magnetic resonance imaging (MRI) or a contrast-enhanced computed tomography (CT) scan. An elevated ESR may be supporting evidence for a diagnosis of temporal arteries. With respect to sinusitis, facial X-rays are of very limited value.