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Case Report: Imaging Findings in COVID-19 Muscle Denervation Atrophy

Key findings

  • This case report describes a 63-year-old man hospitalized with COVID-19 who developed acute left leg weakness four days after being extubated
  • Four months later, the patient reported no improvement, and he had developed paresthesias from his left posterior buttock along the posterolateral thigh, anterior shin and lateral calf to the bottom of his left foot
  • Left thigh and lumbosacral plexus MRI revealed multifocal denervation of the muscle of the thigh and mild focal thickening of the sciatic nerve on the left
  • Electromyography demonstrated bilateral mixed sensorimotor axonal polyneuropathy with superimposed left sciatic neuropathy
  • Guillain–Barré syndrome is a peripheral neuropathy commonly described with COVID-19. This case illustrates the MRI findings that may be seen in peripheral neuropathy due to COVID-19

Anosmia and ageusia are common, well-recognized features of COVID-19, but more serious neurologic manifestations can also occur, including peripheral nervous system disease. Sara Bahouth, MD, diagnostic radiologist, and Daniel Rosenthal, MD, musculoskeletal radiologist and senior vice chairman of the Department of Radiology, both of the Division of Musculoskeletal Imaging and Intervention at Massachusetts General Hospital, and colleagues recently described a patient with COVID-19 who developed an unusual case of muscle denervation atrophy with striking MRI findings.

Their paper, which they believe to be the first report of imaging findings in COVID-19 peripheral neurological disease, appears in Skeletal Radiology.

Findings During Hospitalization

The 63-year-old man was hospitalized for 37 days and was admitted to the ICU, where he was intubated for 22 days. On hospital day 25, three days after extubation, the patient was alert and conversant, but the next day he exhibited left leg weakness. He had normal motion of his upper extremities and right leg but little to no movement in his left lower extremity.

Laboratory evaluation was notable for elevated C-reactive protein and erythrocyte sedimentation rate and low creatinine kinase. An antinuclear antibody test was positive and a mitochondrial antibody test was negative.

Post-Discharge Workup

The patient was discharged 11 days after the acute onset of left leg weakness. Four months later, he reported no improvement in symptoms. He had developed paresthesias from his left posterior buttock along the posterolateral thigh, anterior shin and lateral calf to the bottom of his left foot.

Left thigh and lumbosacral plexus MRI revealed multifocal muscular edema of the thigh. The affected muscles included:

  1. Distal and lateral portion of bilateral gluteus maximus
  2. Left gluteus medius and minimus
  3. Left biceps femoris
  4. Left semimembranosus and semitendinosus
  5. Left obturator internus
  6. Left quadratus femoris
  7. To a lesser extent, the muscles of the left anterior compartment, including the vastus lateralis and medialis

Mild focal thickening of the sciatic nerve on the left at the level of the posterior acetabular column was also noted.

Electromyography (EMG) demonstrated:

  1. Bilateral, generalized, length-dependent, mixed sensorimotor axonal polyneuropathy
  2. Superimposed severe left-sided sciatic neuropathy or lumbosacral plexopathy


The multifocal muscular edema in this case doesn't represent isolated sciatic neuropathy, since muscles innervated by multiple other nerves were also affected. Guillain–Barré syndrome is a commonly described peripheral neuropathy in the setting of COVID-19. This case is atypical in that only one side of the body was affected and there were no demyelinating features on EMG. Critical illness polyneuropathy/myopathy and inflammatory myopathy were also considered in the differential diagnosis.

At the time of this writing, nine months after symptom onset, the patient's condition was unchanged. No additional imaging had been done.

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