This document discusses normal pressure hydrocephalus (NPH), a potentially reversible cause of significant morbidities. NPH is characterized by a triad of gait disturbance, urinary incontinence, and dementia. It can be idiopathic or secondary to other conditions like subarachnoid hemorrhage. Diagnosis involves imaging showing enlarged ventricles without cortical atrophy, along with improvement of symptoms after CSF drainage. Shunting procedures may benefit those without severe white matter lesions or dementia, but have high complication rates. The prognosis for NPH is generally poor.

1. NORMAL PRESSURE
HYDROCEPHALUS
POTENTIALLY REVERSIBLE CAUSE
OF SIGNIFICANT MORBIDITIES
DR REMA MURTHY

2. What should physicians know?
 Diagnostic features
 Diagnostic tests
 Limitations of Prognostic test
 Who will benefit from treatment
 Complications of treatment
EXTRAVENTRICULAR OBSTRUCTIVE HYDROCEPHALUS

3. ETIOLOGY
 50% idiopathic
 Impairment of CSF flow
 Waves of increased pressure in intraventricular studies
(B waves).
 50% secondary to other problems
 SAH
 Meningitis
 Cranial trauma.
 CNS tumour.
 Secondary NPH has higher response to shunting than idiopathic.

4. PATHOPHYSIOLOGY
 Ventricle enlargement leads to periventricular
ischemia regardless of etiology
 Compression and stretching of arterioles and
venules
 Arterial hypertension and cerebral
arteriosclerosis increased in NPH

5. CSF CIRCULATION
 CSF produced by choroid plexus at rate
approximately 20 ml/hr
 Flows from lateral ventricles through
foramina of
Monro into third ventricle
 Enters fourth ventricle through aqueduct of
Sylvius
 Enters subarachnoid space
 Resorbed by arachnoid villi at top of brain

6. Diagnosis : TRIAD
 Gait Disturbance
 Urinary Incontinence
 Dementia

7. Gait disturbance
DISTORTION OF CORONA RADIATA DUE TO VENTRICULOMEGALY. OR OF PEDUNCLES(
PONS).
 No classic gait disturbance – GAIT APRAXIA.
 Gait may be wide based, shuffling and slow.
 More severely affected patients have magnetic gait- feet stuck to ground and difficult
to initiate walking
 Difficulties with walking motions resolve with minimal support of patient or lying
patient down
 May resemble Parkinsons gait but no rigidity/ tremor/ response to carbidopa.
 Not associated with limb weakness
 Hyperreflexia

8. Urinary Incontinence
DUE TO STRETCHING OF PERIVENTRICULAR NERVE FIBERS AND LOSS OF DETRUSOR
INHIBITION
 True incontinence found only in severely affected patients
 Urinary urgency in most patients with NPH
 Bladder sphincter muscle unaffected
 Occasionally bowel incontinence as well.

9. Dementia
DISTORTION OF PERIVENTRICULAR LIMBIC SYSTEM.
 Presence of dementia in NPH extremely variable
 Some shunt responsive patients have little or no dementia
 Dementia usually least responsive of symptoms to intervention
 Mental status changes may resemble depression
 Memory loss, inattention, inertia, bradyphrenia ( slowness of thought).
 Very slow progression ( unlike Alzheimer’s).

10. Differential diagnosis
 Depression
 Subcortical arteriosclerotic encephalopathy
 Multi-infarct encephalopathy
 Chronic alcoholism
 B12, Folate deficiency
 Electrolyte abnormalities
 Cervical or lumbar stenosis
 Peripheral neuropathy
 PARKINSON’S DISEASE
 ALZHEIMER’S DEMENTIA

11. Imaging

12. Imaging appearances
 Ventricles enlarged- ratio of frontal horn to the internal transverse diameter is
>0.32
 Lack of hippocampus or cortical atrophy
 Periventricular and cortical white matter lesions

13. INVESTIGATIONS
SPINAL TAP TEST
 CSF pressure is mostly normal. Occ mildly
elevated.
 Assess gait/ MMSE first then LP to drain
large volume of CSF. Reassess gait/ MMSE
–sustained significant clinical
improvement indicates good response to
shunting.
 Limited use in diagnosis.
LUMBAR INFUSION TEST
 Test with fluid challenge to the csf
absorptive capacity.
 Abnormal sustained rise in CSF.
 Measures(i) resistance to CSF outflow or(ii)
plateau pressure – to assess response
expected from shunting.

14. Management-Shunting procedures
Benefits those with
 Lack of white matter lesions on MRI
 Clear defined etiology
 Marked resolution of symptoms with CSF
drainage
 B-waves greater than 50 of time with
continuous intracranial pressure (ICP)
monitoring
 Predominant gait symptoms
Poor response if
 Severe dementia
 Dementia presenting symptom
 MRI abnormalities
 Cerebral atrophy
 Multiple white matter lesions

15. OTHER TREATMENTS
 Endoscopic third ventriculostomy
 Acetazolamide with or without serial lumbar punctures( POOR EVIDENCE).
PROGNOSIS– poor.
Complications of CSF shunts 30-40%.

16. THANK YOU
DR REMA MURTHY