Looking for idiopathic intracranial hypertension in patients with chronic fatigue syndrome

Headache is common in chronic fatigue syndrome, a condition of unknown cause in which there are no clinical signs. Fatigue is common in idiopathic intracranial hypertension, a headache condition of unknown cause in which the only clinical signs are those of raised intracranial pressure, signs which may be absent. Might, therefore, idiopathic intracranial hypertension be present in some patients diagnosed with chronic fatigue syndrome? Could the two conditions be related?

From June 2007, patients attending a specialist clinic who fulfilled the diagnostic criteria for chronic fatigue syndrome and in whom headache was an especially prominent symptom were offered CT venography and lumbar puncture, looking for evidence of raised intracranial pressure.

Of the 20 patients who accepted lumbar puncture, eight had pressures of 20 cm H₂O or greater, including three who had pressures of 25 cm H₂O or greater. Mean pressure was 19 cm H₂O.

Some patients with headache and a diagnosis of chronic fatigue syndrome have unrecognised and occult idiopathic intracranial hypertension. The possibility that the two conditions are related cannot be excluded.