| IHS | Diagnosis | ICD-10 |
|---|---|---|
| 7 | HEADACHE ATTRIBUTED TO NON-VASCULAR INTRACRANIAL DISORDER | G44.82 |
General comment
Primary or secondary headache or both?
When a new headache occurs for the first time in close temporal relation to a non-vascular intracranial disorder, it is coded as a secondary headache attributed to the intracranial 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 an intracranial 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 intracranial disorder. Factors that support adding the latter diagnosis are: a very close temporal relation to the intracranial disorder, a marked worsening of the pre-existing headache, very good evidence that the intracranial disorder can aggravate the primary headache and, finally, improvement or resolution of the headache after relief from the intracranial disorder.
Definite, probable or chronic?
A diagnosis of Headache attributed to non-vascular intracranial disorder usually becomes definite only when the headache resolves or greatly improves after effective treatment or spontaneous remission of the causative disorder. If the intracranial disorder cannot be treated effectively or does not remit spontaneously, or when there has been insufficient time for this to happen, a diagnosis of Headache probably attributed to a non-vascular intracranial disorder is usually applied.
The alternative, when the causative disorder is effectively treated or remits spontaneously but headache does not resolve or markedly improve after 3 months, is a diagnosis of A 7.10 Chronic post-intracranial 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
In this chapter are the headaches attributed to changes in intracranial pressure. Both increased and decreased CSF pressure can lead to headache. Other causes of headache here are non-infectious inflammatory diseases, intracranial neoplasia, seizures, rare conditions such as intrathecal injections and Chiari malformation type I, and other non-vascular intracranial disorders.
Compared to those on primary headaches, there are few epidemiological studies on these headache types. Controlled trials of therapy are almost non-existent.
Headache persisting for more than 1 month after successful treatment or spontaneous resolution of the intracranial disorder usually has other mechanisms. Chronic headache persisting for >3 months after treatment or remission of intracranial disorders is defined in the appendix for research purposes. Such headaches exist but have been poorly studied and the appendix entries are intended to stimulate further research into such headaches and their mechanisms.
