Case Series: Post-COVID Small Fiber Neuropathy

ABSTRACT

Objective: To report a case series documenting biopsy-proven small fiber neuropathy (SFN) after COVID-19. Background: Patients recovering from COVID-19 who present with sensory as well as autonomic symptoms, including positional orthostatic tachycardia syndrome (POTS), frequently have negative electrodiagnostic testing. Skin biopsy may be required to reveal SFN. Design/Methods: This is a retrospective case series of patients seen in the Yale Neurology COVID-19 Clinic with positive SARS-CoV-2 PCR or antibody or a clinically consistent illness. After laboratory testing and a negative nerve conduction study, all patients underwent skin biopsy to test for intraepidermal SFN. Case 1 A 40F with pre-diabetes (HbA1c 6.2%) developed burning, numbness, and tingling in the hands and legs and POTS 6 weeks after acute COVID-19. Skin biopsy demonstrated non-length dependent SFN. Complete remission of neuropathy symptoms occurred within days of intravenous immunoglobulin (IVIG) therapy, which has been continued longitudinally. Case 2 A 65F with non-insulin dependent diabetes (HbA1c 8.0%) developed excruciating burning pain in her feet and orthostasis within weeks of acute COVID-19. Skin biopsy demonstrated non-length dependent SFN. She experienced partial relief of symptoms after IVIG and gabapentin. Case 3 A 43F with pre-diabetes (HbA1c 6.0%) developed orthostasis, numbness, paresthesias, and a “sunburned” feeling in her face, back, hands, and feet 2 weeks after acute COVID-19. Skin biopsy demonstrated length-dependent SFN. Symptoms improved over several months of pregabalin treatment, but have not resolved. The patient deferred immunotherapy. Case 4 A 40M developed POTS, numbness, and paresthesias in his face and left leg up to the knee within weeks of a clinical COVID-19 illness. Skin biopsy demonstrated non-length dependent SFN. IVIG therapy has resulted in significant improvement in symptoms. Conclusions: Sensory symptoms and POTS occur post-COVID, and SFN should be considered in the differential. Given the time of onset and response to immunotherapy, post-COVID SFN may have an underlying autoimmune etiology.