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DESTIN, FLORIDA – Central nervous system manifestations in patients with systemic lupus erythematosus should always trigger an evaluation for infection and other non–SLE-related etiologies, according to Dr. Julius Birnbaum.
That’s because between 33% and 50% of SLE patients will have a CNS syndrome that is not caused by SLE, Dr. Birnbaum said at the annual Congress of Clinical Rheumatology.
Dr. Julius Birnbaum
Infection is among the top causes of such syndromes.
"Because lupus patients are on immunosuppressive therapy, there always needs to be this paranoia for this lurking possibility of an infection," stressed Dr. Birnbaum of the departments of medicine and neurology at Johns Hopkins University, Baltimore.
The VITAMIN mnemonic device, similar to the VITAMINS mnemonic device he recommends for developing the differential diagnosis for peripheral nervous system manifestations, can also help with the differential diagnosis for CNS manifestation in neuropsychiatric SLE, he said.
"The stakes are a little bit higher now when we’re dealing with a lupus patient because we really want to make sure that we’re not overlooking a syndrome which would be exacerbated and not helped if we start immunosuppressive therapy," he said.
VITAMIN in this case represents:
• V – Vascular. In terms of stroke, it is important to think about septic emboli, subarachnoid hemorrhage from mycotic aneurysms, and septic thrombophlebitis.
• I – Infections. These should be classified by etiology (that is, bacterial, fungal, viral) and by anatomic region (is it parenchymal or meningeal, or does it have a vascular distribution, as in the case of septic emboli or thrombophlebitis?).
• T – Trauma. In SLE, this cause of CNS symptoms is similar to the general population.
• A – Autoimmune disorders. Always look for other autoimmune diseases as a cause.
• M – Metabolic disorders. These are uncommon as a cause of CNS symptoms, but may include hyperhomocysteinemia and B12 deficiency.
• I – Iatrogenic complications. These are a major concern, and can include metabolic complications associated with steroid use or infections caused by immunosuppressive therapy.
• N – Neoplastic syndromes.
Dr. Birnbaum suggested using the VITAMIN mnemonic to get ideas for potentially useful diagnostic strategies, including routine serologic studies (such as an evaluation for uremia as a cause for encephalopathy or seizures); a work-up for infection (possibly including lumbar puncture); neuroimaging studies (such as CT to exclude a hemorrhage and MRI to further characterize space occupying lesions using specific sequences for strokes, for example); and diagnostic-specific strategies for distinct CNS disorders, such as EEG for the evaluation of seizures.
"Everything germinates from the patient’s symptoms ... you start with the symptoms, you do your neurological examination, and all of these tests that you’re going to order should be subordinated under a unifying strategy based on just the symptom and the examination," he said.
The next step, after reviewing the differential diagnosis, is to consider the specificity of a particular CNS syndrome for neuropsychiatric SLE, Dr. Birnbaum said.
Importantly, among the syndromes included in the American College of Rheumatology neuropsychiatric SLE nomenclature and case definition for the CNS neuropsychiatric SLE spectrum are several that have been shown – since the list was developed 15 years ago – to be nonspecific in that they are seen with similar frequency in non-SLE controls, he said.
These include headache, mood disorders, anxiety disorders, and mild cognitive impairment. In most cases, once "sinister causes" are ruled out using the VITAMIN mnemonic, these can be evaluated and treated as if the patient does not have SLE.
Only rarely are these nonspecific syndromes actually a manifestation of pathologic mechanism specific to SLE. In the right clinical context, examples may include an intractable "lupus headache" and depression or depression with unusual catatonic features, Dr. Birnbaum said.
"These are extraordinarily uncommon ... I want to emphasize that a neurological work-up can be standardized, but it is layered with some nuance, so there is no substitute for individual judgment," he said.
As for decisions regarding instituting symptomatic vs. immunosuppressive therapy, much of the decision will be based on the timing of the onset of symptoms relative to the onset of lupus.
"By and large, neurological symptoms that occur early into the onset of lupus tend to be more associated with lupus disease. Those neurological symptoms that occur later tend to be associated with damage," he said.
Seizures that occur in a young adult within 2 years of the onset of lupus, for example, tend to be associated with extraneurologic disease activity and increased organ activity. In this context, institution of immunosuppressive therapy for the extraneurologic disease should be considered.