Test on Acute Disseminated Encephalomyelitis (ADEM)

Question 1: Acute disseminated encephalomyelitis (ADEM) should primarily be suspected in a child developing multifocal neurologic abnormalities and encephalopathy only if symptoms appear more than three weeks after a viral infection.

A. Ano

B. Ne

Explanation: The diagnosis of ADEM should be suspected in a child who develops multifocal neurologic abnormalities with encephalopathy, particularly if the onset occurs within two weeks after a viral infection, not only if it appears more than three weeks after.

Question 2: Which of the following statements accurately describe the proposed autoimmune mechanism in the pathogenesis of Acute Disseminated Encephalomyelitis (ADEM)?

A. Myelin autoantigens like myelin basic protein share antigenic determinants with an infecting pathogen.

B. Antiviral antibodies or a cell-mediated response to a pathogen cross-react with myelin autoantigens, leading to ADEM.

C. The Epstein-Barr virus nuclear antigen (EBNA) contains a sequence that shares homology with an epitope of myelin basic protein.

D. The immunopathologic events of ADEM involve only a single phase of T cell activation and subsequent demyelination.

Explanation: ADEM is considered an autoimmune disorder where myelin autoantigens, such as myelin basic protein, proteolipid protein, and myelin oligodendrocyte glycoprotein, share antigenic determinants with an infecting pathogen. This molecular mimicry leads to antiviral antibodies or a cell-mediated response to the pathogen cross-reacting with myelin autoantigens. The Epstein-Barr virus nuclear antigen (EBNA) is given as an example, sharing a pentapeptide sequence with an epitope of myelin basic protein. The immunopathologic events involve two major phases: initial T cell priming and activation, and subsequent recruitment and effector phase, followed by repair and remyelination, not just a single phase.

Question 3: Are metabolic studies for genetic disorders or inborn errors of metabolism, when suspected as ADEM mimics, best performed after fluid resuscitation due to potential normalization of some tests?

A. Ano

B. Ne

Explanation: Metabolic studies for genetic disorders and inborn errors of metabolism are best performed in the acute presentation, as some tests may normalize with fluid resuscitation, making it critical to perform them before such normalization occurs.

Question 4: The anti-AQP4 IgG antibody is a specific biomarker used to establish the diagnosis of Acute Disseminated Encephalomyelitis (ADEM).

A. Ano

B. Ne

Explanation: The study materials state that the anti-AQP4 IgG antibody is a specific biomarker for neuromyelitis optica spectrum disorder (NMOSD). It also explicitly mentions that "There are no specific biomarkers or confirmatory tests to establish the diagnosis of ADEM. The diagnosis is based upon the clinical and radiologic features".

Question 5: According to the provided study materials, for what purpose can serum and CSF next generation sequencing techniques be utilized in the context of ADEM diagnostics?

A. To test for the myelin oligodendrocyte glycoprotein (MOG) IgG autoantibody.

B. To identify a broad array of potential causative pathogens.

C. To analyze for elevation of serum or CSF lactate.

D. To perform a brain biopsy to rule out CNS malignancy.

Explanation: Serum and CSF next generation sequencing techniques utilizing polymerase chain reaction (PCR) and other DNA-based methods can be a useful test to further identify a broad array of potential causative pathogens.