Multiple sclerosis is an autoimmune disease of the central nervous system. Balo's disease, or concentric sclerosis, is an unusual variant that tends to progress rapidly.
The American Autoimmune Related Diseases Association web site reports that symptoms include headache, gradual paralysis, seizure, involuntary muscle spasm, and loss of cognitive function.
Other names for this condition include encephalitis periaxialisis concentrica, and leukoencephalitis periaxalis concentric.
The term “concentric” refers to the appearance of magnetic resonance images (MRI) of the brain. Steffi F. Dreha-Kulaczewski of Georg August University in Germany and colleagues reported an imaging study of a female patient who was 13.8 years old when her symptoms first appeared. The white matter of the patient's brain showed “large concentric ring-like or whorled-appearing lesions.”
The gray matter of the brain is composed primarily of the bodies of nerve cells called neurons. Each neuron typically has a long extension called an axon, along with many shorter extensions called dendrites.
Sebastian Seung of MIT described the axons and dendrites as the wiring of the brain. The white matter is composed primarily of axons. They are normally covered with a protective sheath called myelin.
Damage to the myelin causes scar tissue called sclerosis. The National Multiple Sclerosis Society explains that nerve impulses are distorted or interrupted by sclerosis, causing symptoms.
In Balo's disease, the sclerosis occurs in bands, leaving layers of tissue undamaged between bands. Dreha-Kulaczewski explained that this pattern of demyelinated white matter produces the images seen on MRI.
The onset of Balo's disease can look like a stroke, according to Ellen M. Mowry of the University of Pennsylvania and colleagues. “BCS [Balo's concentric sclerosis] can affect any area of the brain, optic chiasm, or spinal cord, so it could potentially cause almost any neurological symptom,” Mowry reported.
Treatment options include steroids and mitoxantrone, which is also used as a cancer chemotherapy agent.