A 70 year old man comes to clinical attention with progressive memory loss, urinary incontinence, and gait instability. MRI of the brain shows dilatation of the ventricular cavities, while the cerebral coex appears normal. No infarcts are seen. Repeated lumbar punctures reveal occasional increases in cerebrospinal fluid (CSF) pressure. A biopsy of the frontal coex demonstrates the absence of neurofibrillary tangles and senile plaques. Which of the following is the most appropriate treatment?

**Core Concept**
Normal pressure hydrocephalus (NPH) is a clinical syndrome characterized by the triad of gait disturbance, dementia, and urinary incontinence, often associated with enlarged ventricles and normal cerebral cortex on imaging. The pathophysiology involves impaired cerebrospinal fluid (CSF) absorption, leading to increased intracranial pressure.

**Why the Correct Answer is Right**
The correct diagnosis of NPH is supported by the presence of ventricular dilatation with a normal cerebral cortex, absence of neurodegenerative markers in the biopsy, and increased CSF pressure on lumbar puncture. The treatment of choice for NPH is ventriculoperitoneal shunting, which aims to reduce intracranial pressure by diverting CSF into the peritoneal cavity.

**Why Each Wrong Option is Incorrect**
**Option A:** Acetylcholinesterase inhibitors, such as donepezil, are used in Alzheimer's disease but are not the primary treatment for NPH.
**Option B:** Cholinesterase inhibitors can exacerbate urinary incontinence in NPH.
**Option C:** Memantine, an NMDA receptor antagonist, is used in Alzheimer's disease but is not the treatment of choice for NPH.
**Option D:** Steroid treatment is not indicated in NPH and may even worsen the condition.

**Clinical Pearl / High-Yield Fact**
NPH is often misdiagnosed as Alzheimer's disease or other neurodegenerative conditions, highlighting the importance of a thorough clinical evaluation and imaging studies in diagnosing this condition.

**Correct Answer:** C. Ventriculoperitoneal shunting is the most appropriate treatment for NPH.

✓ Correct Answer: D. Ventricular shunt