A 60-year-old man with long-standing type 2 diabetes mellitus comes to the physician due to progressive weakness. Six months ago he started experiencing tingling and numbness in his feet. A few weeks later he experienced similar symptoms in his hands. Over the last 2 months he has been having increasing difficulty rising from a chair, going up stairs, and lifting objects. He does not have slurred speech, difficulty breathing, changes in vision, bowel or bladder dysfunction, or back pain.
His neurological examination reveals symmetric, proximal and distal, and upper and lower extremity muscle weakness associated with atrophy. He has reduced vibration, proprioception, and pinprick sensation that is worse in the legs compared to his arms. His reflexes are diminished in the upper extremities and absent in the lower extremities. Plantar responses are flexor bilaterally.
Which of the following is the most likely diagnosis?

Question

A 60-year-old man with long-standing type 2 diabetes mellitus comes to the physician due to progressive weakness.  Six months ago he started experiencing tingling and numbness in his feet.  A few weeks later he experienced similar symptoms in his hands.  Over the last 2 months he has been having increasing difficulty rising from a chair, going up stairs, and lifting objects.  He does not have slurred speech, difficulty breathing, changes in vision, bowel or bladder dysfunction, or back pain.
His neurological examination reveals symmetric, proximal and distal, and upper and lower extremity muscle weakness associated with atrophy.  He has reduced vibration, proprioception, and pinprick sensation that is worse in the legs compared to his arms.  His reflexes are diminished in the upper extremities and absent in the lower extremities.  Plantar responses are flexor bilaterally.
Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

This patient is likely presenting with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). CIDP is an acquired inflammatory disorder characterized by demyelination of the peripheral nerves and nerve roots. It classically presents with progressive, symmetric, proximal, and distal muscle weakness along with distal sensory loss affecting the arms and legs. Symptoms typically develop over >8 weeks, which helps to differentiate CIDP from acute inflammatory demyelinating polyneuropathy (AIDP). Distal sensory loss is normally more selective for vibration and proprioception due to the greater involvement of larger myelin fibers. Diminished or absent deep tendon reflexes is also characteristic. Diagnosis is made clinically and supported with electrodiagnostic studies demonstrating peripheral nerve demyelination (eg, reduced conduction velocity and prolonged distal motor latencies). Lumbar puncture can show albuminocytologic dissociation in 90% of patients. The sensitivity and specificity of nerve biopsy is limited, but it can be used to help confirm segmental myelin loss when electrodiagnostic studies are indeterminate. (Choice A) Amyotrophic lateral sclerosis (ALS) is a progressive degenerative upper and lower motor neuron disease. Although this patient has lower motor neuron signs (eg, diminished deep tendon reflexes and muscle atrophy), upper motor neuron signs (eg, hyperreflexia and Babinski sign) are not evident. In addition, sensory symptoms may occur in 20%-30% of patients with ALS, but objective sensory deficits are usually not present. (Choice C) Diabetic polyneuropathy presents with very slowly progressive (over years), symmetric, and predominantly distal sensory symptoms. Motor symptoms can occur in severe cases. This patient's proximal muscle weakness and symptom progression over weeks to months make the diagnosis less likely. (Choice D) AIDP, also known as Guillain-Barré syndrome, has a rapid onset of symptoms which usually reaches nadir within 3-4 weeks. AIDP is also usually associated with an antecedent illness (eg, Campylobacter jejuni infection), HIV infection, or vaccination. (Choice E) Lambert-Eaton myasthenic syndrome is an autoimmune pre-synaptic neuromuscular junction disorder that is associated with malignancy (eg, small cell lung cancer) in about 50% of cases. Patients normally present with slowly progressive, symmetric, proximal muscle weakness that seems to improve with physical activity. Reflexes may become diminished or absent but sensory function is typically preserved. Educational objective: Chronic inflammatory demyelinating polyradiculoneuropathy usually presents with progressive muscle weakness, distal sensory loss, and diminished or absent reflexes developing over >8 weeks. Diagnosis is confirmed with electrodiagnostic studies demonstrating peripheral nerve demyelination. Cerebrospinal fluid analysis will show albuminocytologic dissociation in the vast majority of cases. __________ References: Diagnosis and treatment of chronic acquired demyelinating polyneuropathy. (http://www.ncbi.nlm.nih.gov/pubmed/24980070)

A 60-Year-Old Man with Long-Standing Type 2 Diabetes Mellitus Comes