Diagnosis:
A combination of clinical features, response to high volume lumbar puncture spinal tap plus imaging
Clinical features:
Gait disorder, the first symptom:
- Marche a petis pas: wide-based slow shuffling gait
- Ignition failure: hesitation on starting to walk
- Magnetic foot: difficulty lifting foot of the ground
- Poor postural control
Cognitive impairment:
- Apathy, memory impairment
Urinary incontinence & frequency: late finding
Other findings:
- grasp reflex, no papilledema, no paresis, no ataxia, normal alternate movements, no rigidity, no tremor,
Findings on Investigations:
CT:
- Large ventricles, normal sulci.
- No evidence for CSF flow obstruction
MRI:
- Large ventricles, normal sulci.
- No evidence for CSF flow obstruction
- Transependymal edema (egress of CSF) may occur
+High volume LP with gait testing, a modification of the Fisher test:
- Opening pressure usually 15-20 cmH2O
- Walk patient multiple times
- Remove 30ml CSF,
- Walk patient multiple times & observe for improvement
Trial of Lumbar drainage with Temporary catheter in lumbar region
Cisternography i.e. Radionucleotide CSF studies: poor predictive value
Cine-MRI (cine phase contrast):
- Measures cerebral aqueduct CSF stroke volume, if >100 microL suggest shunt responsiveness, if <80 microL suggest shunt unresponsiveness
- This test is controversial
Investigations to consider:
LP with opening pressure & CSF analysis & Fisher test (lumbar tap test)
Imaging
Treatment:
Consider CSF Shunt placement