Co-existence of autoimmune polyglandular syndrome type 3b and undifferentiated connective tissue disease with subacute combined degeneration of spinal cord in children: a case report and literature review

The clinical manifestations of subacute combined degeneration of spinal cord (SCD) in children are complex and vary greatly. Notably, some SCD patients may be complicated with autoimmune diseases, leading to high early misdiagnosis and missed diagnosis rates.

In this study, a case involving an adolescent female with repetitive severe anemia, multiple joint swelling and pain in the left limbs, and paralysis of the bilateral lower limbs with serum vitamin B12 deficiency, polyglandular involvement, and various positive auto-antibodies (anti‑intrinsic factor antibody, anti‑parietal cell antibody, thyroid peroxidase antibody, thyroid globulin antibody and perinuclear anti‑neutrophil cytoplasmic antibody) is reported. The patient was diagnosed with SCD co-existing with autoimmune polyglandular syndrome type 3b (APS 3b) and undifferentiated connective tissue disease (UCTD) based on the symptoms and laboratory tests. However, treatment with high-dose intravenous methylprednisolone pulses, intravenous immunoglobulin, oral naproxen (changed to hydroxychloroquine after 2 weeks), vitamin B12, levothyroxine sodium tablets supplementation, blood transfusion, and rehabilitation significantly improved the patient’s condition.

Co-existence of APS 3b, UCTD, and SCD is rare in children with significantly different clinical manifestations. Nonetheless, early diagnosis and timely treatment of SCD are crucial for improving patient outcomes.