Differential Diagnosis
The patient's symptoms of lower extremity weakness, difficulty walking, and decreased sensation over the lateral aspect of the left calf and dorsum of the foot suggest a neurological condition. The following differential diagnoses are considered:
- Single most likely diagnosis
- B) Common peroneal neuropathy: This condition is characterized by weakness in dorsiflexion of the foot and toe extension, decreased sensation over the lateral aspect of the calf and dorsum of the foot, and absent ankle reflex. The patient's symptoms and examination findings, including the specific pattern of muscle weakness and sensory loss, are consistent with common peroneal neuropathy.
- Other Likely diagnoses
- E) Sciatic neuropathy: Sciatic neuropathy could also explain the patient's symptoms, particularly the weakness in the lower extremity and decreased sensation. However, the specific pattern of muscle weakness and sensory loss is more suggestive of common peroneal neuropathy.
- C) Lumbosacral plexopathy: Lumbosacral plexopathy could cause lower extremity weakness and sensory loss, but the patient's symptoms are more localized to the distribution of the common peroneal nerve.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- A) Anterior cerebral artery infarction: Although less likely, an anterior cerebral artery infarction could cause lower extremity weakness. However, the patient's symptoms are more suggestive of a peripheral neuropathy, and there are no other signs of a stroke, such as cranial nerve deficits or mental status changes.
- Rare diagnoses
- D) S1 radiculopathy: S1 radiculopathy could cause weakness in plantarflexion of the foot and decreased sensation over the lateral aspect of the foot. However, the patient's symptoms are more consistent with common peroneal neuropathy, and S1 radiculopathy would not typically cause weakness in dorsiflexion of the foot.
- Other rare diagnoses, such as a tumor or infection affecting the peripheral nerves, are possible but less likely given the patient's presentation and lack of other symptoms.