IHS	Diagnosis	ICD-10
6	HEADACHE ATTRIBUTED TO CRANIAL OR CERVICAL VASCULAR DISORDER	G44.81

General comment

Primary or secondary headache or both?

When a new headache occurs for the first time in close temporal relation to a vascular disorder, it is coded as a secondary headache attributed to the vascular disorder. This is also true if the headache has the characteristics of migraine, tension-type headache or cluster headache. When a pre-existing primary headache is made worse in close temporal relation to a vascular disorder, there are two possibilities, and judgment is required. The patient can either be given only the diagnosis of the pre-existing primary headache or be given both this diagnosis and the diagnosis of headache attributed to the vascular disorder. Factors that support adding the latter diagnosis are: a very close temporal relation to the vascular disorder, a marked worsening of the pre-existing headache, very good evidence that the vascular disorder can aggravate the primary headache and, finally, improvement of the headache after the acute phase of the vascular disorder.

Definite, probable or chronic?

A diagnosis of Headache attributed to vascular disorder usually becomes definite only when the headache resolves or greatly improves within a specified time after its onset or after the acute phase of the disorder. When this is not the case, or before the specified time has elapsed, a diagnosis of Headache probably attributed to vascular disorder is usually applied. The alternative, when headache does not resolve or greatly improve after 3 months, is a diagnosis of A6.8 Chronic post-vascular-disorder headache. This is described only in the appendix as such headaches have been poorly documented, and research is needed to establish better criteria for causation.

Introduction

The diagnosis of headache and its causal link is easy in most of the vascular conditions listed below because the headache presents both acutely and with neurological signs and because it often remits rapidly. The close temporal relationship between the headache and these neurological signs is therefore crucial to establishing causation.

In many of these conditions, such as ischaemic or haemorrhagic stroke, headache is overshadowed by focal signs and/or disorders of consciousness. In others, such as subarachnoid haemorrhage, headache is usually the prominent symptom. In a number of other conditions that can induce both headache and stroke, such as dissections, cerebral venous thrombosis, giant cell arteritis and central nervous system angiitis, headache is often an initial warning symptom. It is therefore crucial to recognise the association of headache with these disorders in order to diagnose correctly the underlying vascular disease and start appropriate treatment as early as possible, thus preventing potentially devastating neurological consequences.

All of these conditions can occur in patients who have previously suffered a primary headache of any type. A clue that points to an underlying vascular condition is the onset, usually sudden, of a new headache, so far unknown to the patient. Whenever this occurs, vascular conditions should urgently be looked for.

For all vascular disorders listed here, the diagnostic criteria include whenever possible:

Note: