Disclosures: Austin T. Coale: No financial relationships or conflicts of interest

Case Diagnosis: Lumbosacral Plexopathy following Infection with Varicella Zoster Virus

Case Description or Program Description: The patient had a known history of varicella zoster virus (VZV) infection in the upper lumbar region. She presented for new onset right leg weakness which was progressive over several weeks. She also reported burning pain distal to the knee on the right side. Physical exam revealed diminished sensation distal to the right knee and diminished strength throughout the right leg. The patellar reflex was 0 on the right compared to 2+ on the left, absent bilaterally at the ankles. Residual shingles lesions were still present at the time of exam. She was referred for electromyography (EMG) analysis for the evaluation of lumbosacral (LS) plexopathy, which demonstrated slowed conduction velocities and acute denervation changes consistent with a right upper lumbar plexopathy. MRI was ordered and did not show compressive lesion or mass, further confirming a VZV induced plexopathy.

Setting: Outpatient Rehabilitation Clinic

Assessment/Results: A 10-day course of valacyclovir (Valtrex) was initiated. Patient was started on pregabalin (Lyrica) 75mg BID, which was helpful in controlling the pain. Patient had continued improvement and resolution of symptoms.

Discussion (relevance): LS plexopathy caused by VZV infection is a rare occurrence and has only a few case reports describing this phenomenon. Combination of EMG and MRI can be helpful in diagnosis, though there may be no abnormalities seen on imaging. This diagnosis requires a detailed physical exam and history as well as diagnostic lab testing such as VZV serology. Treatment for LS plexopathy varies based on the etiology of the condition; therefore, it is vital to consider VZV infection and start prompt antiviral therapy upon confirmation of diagnosis.

Conclusions: While not common, lumbosacral plexopathy following a known Varicella Zoster Virus infection should raise clinical suspicion of a zoster-associated plexopathy. Keeping this as a differential diagnosis is important since treating the underlying cause requires antiviral medication, a unique treatment for LS plexopathy that requires an accurate diagnosis.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/lumbosacral-plexopathy-following-infection-with-varicella-zoster-virus-a-case-report/