Unraveling MOGAD: A Rare Case of Pediatric Longitudinally Extensive Transverse Myelitis

Abstract

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is an autoimmune central nervous system demyelinating condition. It has a wide range of clinical presentations, such as optic neuritis, acute disseminated encephalomyelitis (ADEM), and transverse myelitis. Longitudinally extensive transverse myelitis (LETM) is a characteristic presentation, usually involving extensive spinal cord segments. This case report outlines an 11-year-old male patient who came with progressive weakness of the lower limbs, sensory impairment, and autonomic dysfunction, eventually diagnosed with MOGAD-associated LETM. The diagnosis was made by MRI abnormalities and the presence of MOG-antibodies in serum and cerebrospinal fluid (CSF). This case highlights the significance of early detection and proper immunotherapy in pediatric MOGAD.

Introduction

MOGAD is an autoantibody-mediated inflammatory demyelination disorder with autoantibodies against myelin oligodendrocyte glycoprotein (MOG). It presents with overlapping yet distinct features with neuromyelitis optica spectrum disorders (NMOSD) and multiple sclerosis (MS). MOGAD often affects children and young adults but is presented by a range of neurological manifestations ranging from optic neuritis, ADEM, and myelitis. LETM, a lesion of the spinal cord that spans three or more vertebral segments, is an important clinical and radiologic finding in MOGAD. MOGAD should be differentiated from other demyelinating diseases for prognostication and treatment planning.

Case Presentation

An 11-year-old previously healthy boy with gradual numbness and weakness of both lower extremities over two days. Six days before admission, he had had an unexplained fall but no significant neurological symptoms initially. Over the subsequent two days, he developed quadriplegia with sensory loss below the nipple line (T4 dermatome), plus bowel and bladder dysfunction.

Neurological Examination

• Muscle strength: 3/5 in lower limbs, normal in upper limbs

• Reflexes: Absent knee, abdominal, and cremasteric reflexes

• Sensory deficits: Diminished light touch and pinprick sensation below T4

• Coordination: Upper extremities intact; lower extremities untestable due to weakness

Laboratory Investigations

• White blood cell count: 15.92 × 10⁹/L (elevated)

• Neutrophils: 93% (elevated)

• C-reactive protein: 11 mg/L (elevated)

• CSF analysis:

  • Cell count: 550 × 10⁹/L

  • Nucleated cells: 420 × 10⁶/L

  • Protein: 45 mg/dL

  • Glucose: 60 mg/dL

• Autoimmune and demyelinating antibody panel:

  • MOG-IgG: Positive (1:100 in serum, 1:1 in CSF)

  • Aquaporin-4 (AQP4) antibodies: Negative

Imaging Findings

Spinal MRI was noted to have hyperintense T2-weighted signal changes between C2 and T6, mostly involving the gray matter and having the characteristic "H-sign." Post-contrast images revealed enhancement in the posterior white matter but not in the gray matter. Cranial MRI had several non-enhancing hyperintense lesions in the bilateral cerebral hemispheres, right basal ganglia, pons, and medulla.

Diagnosis

The clinical presentation, MRI findings, and positive MOG-antibody serology confirmed the diagnosis of MOGAD-associated LETM.

Treatment Course

The patient was treated with high-dose intravenous methylprednisolone (1 g/day for five days) and an oral steroid taper. Because of ongoing deficits, intravenous immunoglobulin (IVIG) (2 g/kg over two days) was given. The patient improved gradually in motor function and sensory deficits over four weeks.

Discussion

MOGAD is increasingly understood as a unique autoimmune disease with varied neurological presentations. LETM is an important presentation in pediatric MOGAD and tends to affect both gray and white matter of the spinal cord. MRI features, such as the "H-sign" in the gray matter, distinguish MOGAD from NMOSD and MS. Although high-dose corticosteroids are still the first-line therapy, IVIG and plasmapheresis can be necessary in refractory cases. Early diagnosis and proper immunotherapy can enhance outcomes and decrease long-term disability in children with MOGAD.

Conclusion

MOGAD must be thought of in kids with LETM, especially the "H-sign" on MRI. Early identification and initiation of immunotherapy is crucial for enhanced neurological recovery. Additional research will be necessary to investigate optimal long-term treatment practices in pediatric MOGAD.

References

1. Hacohen Y, Banwell B. "Treatment Approaches for MOGAD in Children: A Review." Neurology: Neuroimmunology & Neuroinflammation, 2021;8(5):e1064.

2. Jurynczyk M, Messina S, Woodhall MR, et al. "Clinical Course and Prognostic Factors in MOG-antibody Associated Disease: A Multicenter Study." Journal of Neurology, Neurosurgery & Psychiatry, 2017;88(2):127-136.

3. Cobo-Calvo Á, Ruiz A, Maillart E, et al. "Clinical Spectrum and Prognostic Value of CNS MOG Autoimmunity in Adults: The French Cohort Study." Neurology, 2018;90(21):e1858-e1869.