gms | German Medical Science

Objective: Idiopathic intracranial hypertension (IIH) mostly occurs in obese young women, where there is a 20times higher incidence in this group than in the general population (19,4/100.000 vs. 0,9-1/100.000). Familial cases of IIH are extremely rare, with only 2 sets of homozygous twins previously reported.

Method: The first patient developed photopsias and retrobulbar pain on the left side along with headache and dizziness at age 25. Ophthalmological examination revealed bilateral papilledema and peripapillary bleeding in the left upper temporal quadrant. The homozygotic twin presented with a history of four months of severe headaches and blurry vision on the left eye at age 28. Ophthalmological examination revealed papilledema on the left side. Both patients were severely obese (BMI>40) and had an elevated cerebrospinal fluid opening pressure (45 and 34 cm H₂O respectively). MRI demonstrated normal brain parenchyma without evidence of hydrocephalus, mass effect or structural lesions. In both patients an epidural sensor for measurement of intracranial pressure (ICP) was implanted. During the nocturnal recordings, special attention was paid to the dynamics of ICP during sleep.

Results: ICP recordings during six hours of sleep showed an overall increased ICP base line pressure. All traces were characterized by transient ICP elevations of variable duration and amplitude. Complexity measures showed homogeneous results within patients' nightly sleep episodes outlining deterministic/predictable properties in ICP signals. In both cases a ventriculoperitoneal shunt (proGAV^® valve) with an integrated shunt assistant at an opening pressure of 6 cm H₂O was implanted. The ventricular catheter was inserted using an electromagnetic-guided neuronavigation system. On discharge both patients' symptoms were completely resolved and no recurrence was documented at last follow-up.

Conclusions: Familial IIH has been reported previously only in two sets of homozygous twins. In the first set, IIH was triggered by Vitamin A intoxication in identical twin brothers. In the second set, enlarged ventricles make the diagnosis of IIH questionable. In our twin sisters, no exogenous agent aetiologically related to IIH was present. Familial IIH, although exceedingly rare, suggest genetic factors to be relevant. Thorough screening of family members of IIH patients may lead to better understanding of the pathophysiology of IIH.