Introduction: Small fiber neuropathy (SFN) has consensus case definitions, diagnostic criteria, and common etiologies established in adults, but is poorly recognized in children. Lack of awareness of this condition hampers patient care and can impair physical and mental well-being, education, and family finances. We present two severe cases to illustrate the spectrum of presentations and possible associations with underlying medical conditions.

Methods and Results: We report two patients (Table 1) with skin-biopsy proven SFN with debilitating dysautonomia who have undergone extensive work up and trial of multiple immunotherapeutic agents for management of SFN (Table 2).

Both cases had incomplete resolution of symptoms with intravenous immunoglobulin (IVIG) and intravenous Rituximab (CD20 antibody). Both had complications of aseptic meningitis with IVIG. Intravenous Rituximab (CD20 antibody) was discontinued following septic shock in case 1 and severe abdominal pain and loss of sensation to defecate in case 2.

Conclusion: SFN is an under-recognized disease in the paediatric population where initial presentation can be varied. The symptoms are progressive, prolonged, multisystemic and debilitating. Treatment is predominantly supportive with emerging evidence for use of immunotherapy. Our patients only experienced partial and transient improvement in symptoms following IVIG treatment. The natural course of SFN can be slowly progressive with negative effect on quality of life. There is a need to better define underlying pathophysiology of juvenile onset SFN for clinicians to provide evidence-based recommendations for diagnostic pathways. There is a need to develop validated outcome metrics to enable clinical trials to treat SFN in the paediatric population.

Jia Wei Audrey Lee
National University Hospital Singapore
Singapore

Lawrence Chao Ping Wang
National University Hospital Singapore; Yong Loo Lin School of Medicine , National University of Singapore
Singapore

Xinying Velda Han
National University Hospital Singapore; Yong Loo Lin School of Medicine , National University of Singapore
Singapore