Question
A 36-year-old woman comes to the physician because of a 2-month history of progressively worsening lower back pain and weakness in the lower extremities. The pain is worse with movement and improves with lying down on a flat surface. She was diagnosed with pulmonary tuberculosis 6 months ago and is currently taking isoniazid and rifampin. Physical examination shows sensory loss over the lateral aspect of the mid-thigh, patella, and medial aspect of the right lower leg. Strength is 2/5 with right-sided dorsiflexion and the patellar reflex is absent. An x-ray of the spine shows a paravertebral opacity with anterior wedging of the vertebral body. Which of the following nerve roots is most likely to be affected in this patient?
Show Answer
|
Correct Answer � D
Explanation
|
|
Answer D) L4
A history of radiculopathy symptoms in a patient with primary tuberculosis and x-ray findings of anterior wedging of the vertebral bodies and paravertebral opacity is suggestive of spinal tuberculosis (Pott disease).
L4
-
L4 radiculopathy characteristically manifests with sensory loss extending from the lateral thigh over the patella to the medial lower leg, as seen in this patient.
-
Diminished dorsiflexion would also be expected since innervation of the tibialis anterior muscle is impaired, resulting in difficulties when attempting to walk on heels.
-
This patient’s reduced patellar reflex further supports the diagnosis of impingement of the L4 nerve root as the underlying cause.
S2
-
S2 radiculopathy is relatively rare compared to other radiculopathies and may present with diminished sensation affecting the posterior aspect of the thigh, partly extending down to the posterior leg and the perineum.
-
Moreover, affected individuals often have urinary or fecal incontinence and sexual dysfunction, none of which this patient has.
S1
-
S1 radiculopathy typically presents with sensory deficits involving the posterolateral aspect of the thigh, anterolateral as well as posterolateral lower leg, and the lateral foot, which is inconsistent with this patient’s presentation.
-
Moreover, an impinged S1 nerve root would not affect the patellar reflex but would instead lead to diminished ankle jerk reflex in combination with difficulty walking on toes due to impaired innervation of the gastrocnemius, peroneus longus, and peroneus brevis muscles.
L3
-
L3 radiculopathy typically manifests with impaired sensation extending from the anterolateral thigh to the medial thigh just above the patella, unlike the deficits seen in this patient.
-
While affected individuals may present with reduced patellar and/or adductor reflex, they will not have any specific motor deficits, as this patient has.
Like this:
Like Loading...
