(See also Overview of the Peripheral Nervous System Overview of the Peripheral Nervous System The peripheral nervous system refers to the parts of the nervous system that are outside the central nervous system, that is, those outside the brain and spinal cord. Thus, the peripheral nervous... read more .)
Multiple mononeuropathy typically affects only a few nerves, often in different areas of the body. In contrast, polyneuropathy Polyneuropathy Polyneuropathy is the simultaneous malfunction of many peripheral nerves throughout the body. Infections, toxins, drugs, cancers, nutritional deficiencies, diabetes, autoimmune disorders, and... read more affects many nerves, usually in about the same areas on both sides of the body. However, if multiple mononeuropathy involves many nerves, it may be difficult to distinguish from polyneuropathy.
Several disorders can cause multiple mononeuropathy, and each disorder produces characteristic symptoms.
The most common cause is probably
Other common causes of multiple mononeuropathy include
Vasculitis Overview of Vasculitis Vasculitic disorders are caused by inflammation of the blood vessels (vasculitis). Vasculitis can be triggered by certain infections or drugs or can occur for unknown reasons. People may have... read more
(inflammation of blood vessels, as occurs in polyarteritis nodosa)Infections (such as Lyme disease Lyme Disease Lyme disease is a tick-transmitted infection caused by Borrelia species, primarily by Borrelia burgdorferi and sometimes by Borrelia mayonii in the United States. These... read more
and HIV infection Human Immunodeficiency Virus (HIV) Infection Human immunodeficiency virus (HIV) infection is a viral infection that progressively destroys certain white blood cells and is treated with antiretroviral medications. If untreated, it can cause... read more 
)Direct invasion of the nerve by bacteria, as occurs in leprosy Leprosy Leprosy is a chronic infection usually caused by the bacteria Mycobacterium leprae or Mycobacterium lepromatosis. It results in damage primarily to the peripheral nerves (the nerves... read more
A disorder may affect the nerves all at once or affect them progressively, a few at a time.
People have pain, weakness, abnormal sensations, or a combination of these symptoms in the areas supplied by the affected nerves. Symptoms often begin on one side of the body. When diabetes is the cause, nerves anywhere in the body can be affected, and as a result, weakness may affect any muscle.
Doctors diagnose multiple mononeuropathy based on symptoms and results of a physical examination, but electromyography and nerve conduction tests Electromyography and Nerve Conduction Studies Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Imaging tests commonly used to diagnose nervous system (neurologic) disorders... read more 
are usually done to do the following:
Confirm the diagnosis
Identify the damaged nerves
Determine the severity of the damage
Blood tests may be done to identify a disorder causing multiple mononeuropathy.
Treatment of multiple mononeuropathy depends on the cause.
