What is the most appropriate next step in management for a 72-year-old man with a 7-month history of progressive memory loss, gait disturbance, and urinary incontinence, with magnetic resonance imaging (MRI) findings of ventricular enlargement and a lacunar infarct, and a history of poorly controlled type 2 diabetes mellitus (T2DM) managed with metformin and insulin?

From the Guidelines

The most appropriate next step in management for this 72-year-old man is a lumbar puncture (option E). This patient presents with symptoms suggestive of normal pressure hydrocephalus (NPH), characterized by the classic triad of gait disturbance (difficulty initiating stride, slow walking with barely lifting feet), urinary incontinence ("wet himself"), and cognitive impairment (memory loss, disorientation) 1. The MRI findings of ventricular enlargement without significant cortical atrophy further support this diagnosis. A lumbar puncture serves both diagnostic and potentially therapeutic purposes in NPH. Diagnostically, it can help confirm NPH by measuring opening pressure and analyzing cerebrospinal fluid. Therapeutically, removing CSF during the procedure (a "tap test") may temporarily improve symptoms, which would support the diagnosis and suggest that the patient might benefit from permanent CSF diversion with a shunt.

Some key points to consider in the management of this patient include:

• The importance of early detection and management of cognitive impairment in older adults with diabetes, as highlighted in the standards of medical care in diabetes-2023 1
• The need to prioritize the patient's quality of life and minimize the risk of hypoglycemia and hyperglycemia, particularly in the context of advanced disease or palliative care 1
• The potential benefits and limitations of various pharmacologic interventions, including metformin, insulin, and other agents, in the management of type 2 diabetes in older adults 1

The other options are less appropriate:

• Acetazolamide is used for idiopathic intracranial hypertension
• Carbidopa-levodopa is for Parkinson's disease (patient lacks resting tremor)
• Donepezil is for Alzheimer's disease (which typically shows cortical atrophy)
• Increasing insulin would only address diabetes management
• Vitamin B12 measurement, while important in cognitive assessment, is not the most pressing next step given the clinical picture strongly suggesting NPH.

From the Research

Patient Presentation

The patient presents with a 7-month history of memory loss, difficulty paying bills, forgetting recent events, and getting lost. Additionally, the patient has experienced falls and urinary incontinence. The patient has type 2 diabetes mellitus and is taking metformin and insulin.

Clinical Findings

• The patient has trouble initiating stride and walks slowly with a shuffling gait
• No resting tremor is present
• Muscle strength, deep tendon reflex, and sensory examinations are normal
• The patient is oriented to person and time but not to place
• The patient recalls zero of three objects after 2 minutes
• MRI of the brain shows enlargement of all ventricles and a lacunar infarct in the left internal capsule with no cortical atrophy

Differential Diagnosis

• Normal-pressure hydrocephalus (NPH) is a possible diagnosis, given the patient's symptoms of gait impairment, urinary incontinence, and dementia, as well as the radiological findings of ventriculomegaly 2
• Other neurodegenerative disorders, such as Alzheimer's disease or Parkinson's disease, should also be considered in the differential diagnosis

Diagnostic Testing

• A lumbar puncture (LP) or "tap test" may be useful in diagnosing NPH, as it can help to determine if the patient's symptoms improve with removal of cerebrospinal fluid (CSF) 3, 4, 5
• The tap test involves removing a large volume of CSF (typically 40-50 ml) and assessing the patient's symptoms and cognitive function before and after the procedure

Management

• If the diagnosis of NPH is confirmed, treatment with a ventriculoperitoneal shunt may be considered, as it has been shown to improve symptoms in 70-90% of patients 2
• Other management options, such as medication or physical therapy, may also be considered, depending on the patient's specific symptoms and needs

Next Steps

• Given the patient's symptoms and radiological findings, a lumbar puncture or "tap test" may be the most appropriate next step in management, as it can help to confirm the diagnosis of NPH and determine if the patient is a candidate for shunt placement 3, 4, 5
• The patient's response to the tap test can be assessed using standardized clinical evaluations, such as gait analysis and cognitive testing 4, 5
• If the patient's symptoms improve with the tap test, shunt placement may be considered as a treatment option 2