Lower limb axonal mononeuropathies as sequelae of COVID-19: a case report and review of literature

BACKGROUND: Neurological symptoms and complications of Coronavirus disease 2019 (COVID-19) were seldom discussed in the literature initially. Neurological symptoms such as headache, dizziness, anosmia, hypogeusia, and neuralgia are, however, now being reported commonly. Mononeuropathies are rare complications of COVID-19, with most cases associated with prolonged intensive care stay. CASE PRESENTATION: A 61-year-old gentleman with prior history of well-controlled diabetes and hypertension was recently treated for COVID-19 pneumonia with supplemental oxygen and positive pressure ventilation. He now presented with left-sided foot weakness two weeks after recovering from the viral illness. On examination he had normal bulk and tone and a power of 4/5 in proximal and distal muscles of bilateral lower limbs except for ankle dorsiflexion on the left which was 2/5. He also had absent ankle and knee reflexes bilaterally with bilateral flexor plantar reflexes. Since the patient had no back pain and the sensory system was normal, the lesion was localized to the peripheral nerves and a Nerve Conduction Studies and Electromyography (NCS/EMG) was done. NCS/EMG showed findings suggestive of axonal mononeuropathies. Relevant workup done to identify the cause of mononeuropathy was negative including infectious and autoimmune workup. Since diabetes was well-controlled and he had no intensive care stay his findings were presumed to be associated with resolving COVID-19 infection. The patient underwent aggressive daily physical therapy and has started to show improvement in symptoms. CONCLUSIONS: Complications such as mononeuropathies should be kept in mind in patients recovering from COVID-19 infection, since timely diagnosis can improve clinical outcomes in patients.