Atypical Presentations of Intracranial Hypotension: Comparison with Classic Spontaneous Intracranial Hypotension.

BACKGROUND AND PURPOSE: Atypical clinical presentations of spontaneous intracranial hypotension include obtundation, memory deficits, dementia with frontotemporal features, parkinsonism, and ataxia. The purpose of this study was to compare clinical and imaging features of spontaneous intracranial hypotension with typical-versus-atypical presentations. MATERIALS AND METHODS: Clinical records and neuroimaging of patients with spontaneous intracranial hypotension from September 2005 to August 2014 were retrospectively evaluated. Patients with classic spontaneous intracranial hypotension (n = 33; mean age, 41.7 ± 14.3 years) were compared with those with intracranial hypotension with atypical clinical presentation (n = 8; mean age, 55.9 ± 14.1 years) and 36 controls (mean age, 41.4 ± 11.2 years). RESULTS: Patients with atypical spontaneous intracranial hypotension were older than those with classic spontaneous intracranial hypotension (55.9 ± 14.1 years versus 41.7 ± 14.3 years; P = .018). Symptom duration was shorter in classic compared with atypical spontaneous intracranial hypotension (3.78 ± 7.18 months versus 21.93 ± 18.43 months; P = .015). There was no significant difference in dural enhancement, subdural hematomas, or cerebellar tonsil herniation. Patients with atypical spontaneous intracranial hypotension had significantly more elongated anteroposterior midbrain diameter compared with those with classic spontaneous intracranial hypotension (33.6 ± 2.9 mm versus 27.3 ± 2.9 mm; P < .001) and shortened pontomammillary distance (2.8 ± 1 mm versus 5.15 ± 1.5 mm; P < .001). Patients with atypical spontaneous intracranial hypotension were less likely to become symptom-free, regardless of treatment, compared with those with classic spontaneous intracranial hypotension (χ(2) = 13.99, P < .001). CONCLUSIONS: In this sample of 8 patients, atypical spontaneous intracranial hypotension was a more chronic syndrome compared with classic spontaneous intracranial hypotension, with more severe brain sagging, lower rates of clinical response, and frequent relapses. Awareness of atypical presentations of spontaneous intracranial hypotension is paramount.

Neuroprotective effects of GDNF against 6-OHDA in young and aged rats.

In young adult rats, glial cell line-derived neurotrophic factor (GDNF) can completely protect against 6-hydroxydopamine-induced loss of nigral dopamine neurons when administered 6 h prior to the 6-hydroxydopamine. The present study was undertaken to determine if GDNF would provide similar protective effects in aged rats. Male, Fischer 344 x Brown Norway hybrid rats of 3, 18 and 24 months of age were given an intranigral injection of GDNF or vehicle followed 6 h later with an intranigral injection of 6-hydroxydopamine. Nigral dopamine neuron cell survival, and striatal and nigral dopamine and DOPAC levels, were evaluated 2 weeks after the lesions. In vehicle treated animals cell survival on the lesioned side ranged from 15 to 27%. GDNF promoted significant cell survival in the nigra of all three age groups; however, the percent survival was lowest in the 24-month-old animals (85% at 3 months, 75% at 18 months, 56% at 24 months). Similarly, dopamine levels in the striatum and substantia nigra on the lesioned side remained significantly greater in the GDNF treated animals compared to the vehicle treated animals. As with the cell survival experiment, the protective effects of GDNF on dopamine levels were less in the 24-month-old animals. GDNF pretreatment also protected against 6-hydroxydopamine-induced reductions in striatal DOPAC levels in all age groups. Overall, these results indicate that GDNF can protect nigrostriatal dopamine neurons against the effects of 6-hydroxydopamine in aged as well as young adult rats. However, the extent of protection is less in the aged (24-month-old) animals.