Brain Inflammation May Complicate NMOSD Diagnosis
A specific pattern of brain inflammation called BPCLI sometimes can occur in people with neuromyelitis optica spectrum disorder (NMOSD), and often is associated with encephalitis-like symptoms that may contribute to misdiagnoses.
A study with that finding, “Bilateral parafalcine cortical and leptomeningeal impairment: A characteristic pattern of MOG antibody disease and AQP4 neuromyelitis optica spectrum disorders?” was published in the Journal of Neuroimmunology.
A team of scientists reviewed clinical data for 264 people with NMOSD who were treated at one of two hospitals in China. All of the NMOSD patients had tested positive for anti-aquaporin-4 antibodies (AQP4) that drive the autoimmune disease.
The researchers also assessed data for 33 people with a related condition called MOGAD, which is caused by antibodies targeting myelin oligodendrocyte glycoprotein (MOG).
Two (0.7%) of the NMOSD patients and five (15.1%) of those with MOGAD were determined to have BPCLI based on clinical and imaging features.
BPCLI is short for bilateral parafalcine cortical and leptomeningeal impairment, referring to damage in certain parts of the cerebral cortex — the outermost part of the brain — and also the leptomeninges (the two innermost layers that cover the brain and spinal cord). The scientists noted that BPCLI has rarely been reported.
In addition to typical symptoms of NMOSD or MOGAD, the seven patients with BPCLI also reported symptoms that generally are associated with inflammation affecting brain tissue (encephalitis) and/or membranes (meningitis) For example, six of the seven patients experienced seizures, and some reported headache or fever.
The researchers noted that these unusual symptoms frequently contributed to misdiagnoses for the patients. For example, one patient with meningitis-like symptoms during a first attack of BPCLI and optic neuritis — inflammation in the optic nerve, which connects the eyes to the brain — was incorrectly diagnosed initially with an infection.
Another patient, who developed generalized seizures and lower limb weakness at the onset of disease, was misdiagnosed at first with cerebral venous thrombosis, a condition caused by a blood clot in the brain. Two of the patients were misdiagnosed initially with meningitis.
“BPCLI can be observed in both MOGAD and AQP4 NMOSD,” the researchers concluded.
“If patients with BPCLI present with [meningitis and encephalitis]-like attacks and signs, idiopathic inflammatory demyelinating disease, especially MOGAD and NMOSD, needs to be included in the differential diagnosis,” they added.
“Demyelinating” means damage to myelin, the protective covering of nerve fibers. “Idiopathic” means a disease of unknown cause.