Case Presentation: 9 year old girl presented with progressively worsening severe abdominal pain, vomiting, headache, difficulty walking, and confusion for 3 weeks. At age 5 and 7 yrs, she presented with nearly identical symptoms and was diagnosed with ADEM each time. After both episodes she returned to baseline without any residual neurological deficits. CSF studies were normal but MRI showed T2 hyperintense lesions in periventricular white matter tract, pons, and brainstem with normal cervical, thoracic, and lumbar spine. High dose steroids were started and then tapered with remarkable improvement. Of note she developed transient bilateral eye pain and blurry vision by day 3 which resolved after 24 hrs. Differential diagnoses included Multiple Sclerosis, Neuromyelitis Optica, and Acute Intermittent Porphyria. Lab results revealed positive oligoclonal bands in CSF, negative APQ4 antibodies, negative anti-MOG antibodies, low porphobilinogen level and negative 24hr urine random ALA analysis.
Discussion: Majority of patients present with a clinically isolated demyelinating syndrome before an official diagnosis of Multiple Sclerosis (MS) is made. Common symptomatic presentations include sensory symptoms, optic neuritis, limb ataxia or impaired balance, and diplopia. In children the occurrence of headache along with other symptoms is more prevalent compared to adults. Our patient’s chief complaint was intractable abdominal pain. This is an unusual presentation in a pediatric patient. Headache was a minor complaint. While our patient had transient optic neuritis and gait abnormalities, her clinical picture only partially resembled features of Neuromyelitis Optica (NMO). NMO spinal cord involvement is characterized by limb weakness, sensory loss and bladder dysfunction. Her gait abnormalities were due to unsteadiness more typical of ataxia rather than paraparesis. Although her intractable abdominal pain parallels acute attacks seen in Acute Intermittent Porphyria (AIP), her neurological symptoms differed. AIP neurological involvement includes peripheral neuropathy, autonomic phenomenon of tachycardia, hypertension, diaphoresis and bladder dysfunction. Therefore, the combination of her symptoms most likely resembles MS. In addition to negative laboratory findings indicative of NMO and AIP, and positive findings for MS, MRI results further aided in establishing diagnosis. MS diagnosis using McDonald includes several criteria, but 2 categories are relevant to our patient: (1) ≥ 2 attacks with objective clinical evidence of 1 lesion and dissemination in space demonstrated by ≥ 1 T2 lesions involving at least 2 of 4 typical CNS regions such as periventricular, juxtacortical, infratentorial, or spinal cord, or (2) objective clinical evidence of 1 lesion with reasonable historical evidence of prior attack. Our patient’s MRI results demonstrated T2 hyperintense lesions in periventricular white matter extending into the brainstem and pons. She also had significant past medical history of 2 episodes of acute disseminated encephalomyelitis (ADEM). Thus, overall imaging showed 3 episodes of CNS demyelination separated in time and space, characteristic of MS.
Conclusions: Abdominal pain is a rare chief complaint in pediatric patients with MS, but there should be a high index of suspicion even when headache is a minor complaint in the setting of other supporting symptoms and CNS demyelination separated in time and space.