Clinical scenario: Blurred vision / hemiparesis/ spasticity
A 14-year-old girl develops painful blurring of vision in her right eye, which resolves completely after treatment with intravenous methylprednisolone. Eight months later, she presents with progressive weakness and numbness of the left arm and leg. On examination, she is alert and oriented. She has left spastic hemiparesis, hyperreflexia, and an extensor plantar response. Brain MRI demonstrates multiple well-defined ovoid periventricular T2 hyperintense lesions oriented perpendicular to the lateral ventricles, and MRI of the cervical spine shows a focal demyelinating lesion.
What is the most likely diagnosis?
A. Acute disseminated encephalomyelitis
B. MOG antibody-associated disease
C. Multiple sclerosis
D. Neuromyelitis optica spectrum disorder
E. Subacute sclerosing panencephalitis
Correct answer & Explanation:
Correct answer: C Multiple sclerosis
Explanation: Multiple sclerosis
This adolescent has multiple sclerosis (MS), an acquired immune-mediated demyelinating disorder of the central nervous system.
The diagnosis is supported by the following features:
- Two distinct neurological episodes separated by 8 months, demonstrating dissemination in time.
- Involvement of different anatomical sites within the central nervous system—initial optic neuritis followed by a corticospinal tract lesion (spastic hemiparesis)—demonstrating dissemination in space.
- Absence of encephalopathy, which argues against acute disseminated encephalomyelitis (ADEM).
- MRI showing multiple well-defined ovoid periventricular T2 hyperintense lesions oriented perpendicular to the lateral ventricles (“Dawson’s fingers”), a characteristic imaging feature of MS.
According to the McDonald criteria, the diagnosis of MS requires evidence of dissemination in time and dissemination in space, supported by clinical findings and MRI.
Why the other options are incorrect
A. Acute disseminated encephalomyelitis (ADEM)
ADEM is typically a monophasic illness that follows an infection or vaccination and is characterized by encephalopathy with large, poorly demarcated bilateral white matter lesions. Recurrent attacks and the absence of encephalopathy make ADEM unlikely.
B. MOG antibody-associated disease (MOGAD)
MOGAD commonly presents with optic neuritis, ADEM, or transverse myelitis. MRI lesions are usually less typical of MS, and persistent relapsing disease with classic periventricular ovoid lesions (Dawson’s fingers) favors MS. Confirmation requires serum MOG-IgG testing.
C. Multiple sclerosis
Correct. Recurrent demyelinating episodes involving different CNS regions, together with characteristic MRI findings, are typical of pediatric MS.
D. Neuromyelitis optica spectrum disorder (NMOSD)
NMOSD usually presents with severe bilateral optic neuritis and/or longitudinally extensive transverse myelitis (≥3 vertebral segments). Brain MRI is often atypical for MS, and AQP4-IgG antibodies support the diagnosis.
E. Subacute sclerosing panencephalitis (SSPE)
SSPE presents years after measles infection with progressive cognitive decline, behavioral changes, myoclonus, and characteristic EEG abnormalities rather than relapsing focal neurological deficits.
Learning Point
The key features that distinguish multiple sclerosis from ADEM are:
- Recurrent demyelinating attacks
- No encephalopathy
- Well-defined periventricular ovoid lesions (“Dawson’s fingers”) on MRI
- Evidence of dissemination in time and space, which forms the basis of the McDonald diagnostic criteria.
