Headache occurring in patients with HIV infection but caused by a specific opportunistic infection should be coded according to the latter. Headache caused by use of antiretroviral drugs should be coded as 8.1.10 Headache attributed to long-term use of non-headache medication.
- Any headache fulfilling criterion C
- Both of the following:
- systemic HIV infection has been demonstrated
- other ongoing systemic and/or intracranial infection has been excluded
- Evidence of causation demonstrated by at least two of the following:
- headache has developed in temporal relation to the onset of HIV infection
- headache has developed or significantly worsened in temporal relation to worsening of HIV infection as indicated by CD4 cell count and/or viral load
- headache has significantly improved in parallel with improvement in HIV infection as indicated by CD4 cell count and/or viral load
- Not better accounted for by another ICHD-3 diagnosis.
The rationale for separating A9.3 Headache attributed to human immunodeficiency virus (HIV) infection from headaches attributed to other infections is threefold:
- HIV infection is always both systemic and within the central nervous system;
- the central nervous system infection may progress independently of the systemic infection;
- HIV infection is still not curable.
Headache is reported by more than half of people infected by HIV/acquired immune deficiency syndrome (AIDS), and may be a part of the symptomatology of both acute and chronic HIV infection (through aseptic meningitis and similar mechanisms). Nevertheless, A9.3 Headache attributed to human immunodeficiency virus (HIV) infection remains within the Appendix because it is extremely difficult to distinguish headache attributed purely to HIV infection from the primary-like headaches reported by most HIV patients. Application of these criteria in prospective studies may provide more conclusive evidence.
In most cases, A9.3 Headache attributed to human immunodeficiency virus (HIV) infection is dull and bilateral, or has the features of a primary headache disorder (1. Migraine or 2. Tension-type headache). Headache severity, frequency and attributed disability seem to be associated with severity of HIV infection as indicated by CD4 cell count and/or viral load, but not with the duration of HIV infection or the number of prescribed antiretroviral medications.
Only a minority of HIV patients have headache attributable to opportunistic infections, probably as a consequence of the availability of highly-active antiretroviral therapy.
During HIV infection, secondary meningitis and/or encephalitis associated with opportunistic infections or neoplasms can develop. The most common intracranial infections associated with HIV infection and causing headache are toxoplasmosis and cryptococcal meningitis. Headache occurring in patients with HIV infection but attributed to a specific opportunistic infection should be coded to that infection.
Antiretroviral drugs can also cause headache. In these cases, the headache should be coded as 8.1.10 Headache attributed to long-term use of non-headache medication.