Neuromyelitis Optica

Diagnosis

Mayo Clinic doctors perform thorough evaluations to rule out other conditions that have signs and symptoms similar to those of neuromyelitis optica (NMO). Distinguishing NMO from multiple sclerosis (MS) and other conditions ensures that you receive the most appropriate treatment.

Diagnosis of NMO begins with a medical history, questions about your symptoms and a systematic examination of your nervous system. Additional studies include:

• Neurological examination. A neurologist will examine your walk (gait), muscle strength, reflexes, coordination, sensation, memory and thinking (cognitive) function, vision and speech. An eye specialist also may be involved in your examination.
• Magnetic resonance imaging (MRI). An MRI creates images using powerful magnetic fields and radio waves. This test helps your doctor examine your brain, optic nerves and spinal cord. Your doctor may be able to find areas of damage in your nervous system.
• Blood serum tests. Mayo Clinic doctors developed a test for the antibody NMO-IgG, which helps doctors distinguish NMO from MS and other neurological conditions. Your doctor can find this antibody by examining your blood sample, and in some cases, your spinal fluid. This test helps make an early diagnosis of NMO.
• Lumbar puncture (spinal tap). During a spinal tap, your doctor will use a thin, hollow needle to remove small samples of the fluid surrounding your brain and spinal cord (cerebrospinal fluid). The samples will show the levels of immune cells, proteins and antibodies in the fluid. In NMO, the spinal fluid may show markedly elevated white blood cells during episodes, greater than typically seen in MS, although this doesn't always happen. This test may help your doctor differentiate NMO from MS.
• Evoked potentials. Evoked potentials, or evoked response tests, use electrical signals to measure your brain's response to sound, touch and light. A technologist uses a gel to position small wires (electrodes) on your scalp and, in some cases, your earlobes, neck, shoulders and back. Equipment attached to the electrodes records your brain's responses to stimuli. These tests help your doctor find lesions or damaged areas in the brain and brainstem.

Read more about MRI and lumbar puncture at MayoClinic.com.