Muscle biopsy

Alternative Names: Biopsy - muscle

A muscle biopsy is the removal of a small piece of muscle tissue for examination.

Why is the Test Performed?

A muscle biopsy may be done to identify or detect:

• Diseases of the connective tissue and blood vessels (such as polyarteritis nodosa)
• Infections that affect the muscles (such as trichinosis or toxoplasmosis)
• Muscular disorders such as muscular dystrophy or congenital myopathy
• Metabolic defects of the muscle

A muscle biopsy may be also be done to tell the difference between nerve and muscle disorders.

A muscle that has recently been injured, such as by an EMG needle, or is affected by a pre-existing condition, such as nerve compression, is not a good choice for a biopsy.

How is the Test Performed?

This procedure is usually done while you are awake. The health care provider will apply a numbing medicine (local anesthesia) to the biopsy area.

There are two types of muscle biopsy:

A needle biopsy involves inserting a needle into the muscle. When the needle is removed, a small piece of tissue remains in the needle. The tissue is sent to a laboratory for examination. More than one needle stick may be needed to get a large enough sample.

An open biopsy involves making a small cut in the skin and into the muscle. The muscle tissue is then removed.

Preparation for the Test

No special preparation is usually needed.

How will the Test Feel?

During the biopsy, there is usually minimal or no discomfort. You may feel some pressure or "tugging" sensations.

The anesthetic may burn or sting when injected (before the area becomes numb). After the anesthetic wears off, the area may be sore for about a week.

Muscle biopsy Risks

The risks are small, but may include:

• Bleeding
• Bruising
• Damage to the muscle tissue or other tissues in the area (very rare)
• Infection (a slight risk any time the skin is broken)

Normal Results for Muscle biopsy

A normal result means there is normal muscle and related tissue anatomy. There are no abnormalities seen when the tissue sample is stained and examined under a microscope.

What Abnormal Results Mean

A muscle biopsy can help diagnose the following conditions:

• Atrophy (loss of muscle mass)
• Dermatomyositis
• Duchenne muscular dystrophy
• Inflammation of the muscle
• Muscular dystrophy
• Myopathic changes (destruction of the muscle)
• Necrosis (tissue death) of muscle
• Necrotizing vasculitis
• Traumatic muscle damage
• Polymyositis

Additional conditions under which the test may be performed include:

• Becker's muscular dystrophy
• Charcot-Marie-Tooth disease (hereditary)
• Common peroneal nerve dysfunction
• Eosinophilic fasciitis
• Facioscapulohumeral muscular dystrophy (Landouzy-Dejerine)
• Familial periodic paralysis
• Friedreich's ataxia
• Polymyalgia rheumatica
• Senile cardiac amyloid
• Thyrotoxic periodic paralysis

Muscle biopsy

Review Date: 9/16/2010
Reviewed By: Dennis Ogiela, MD, Orthopedic Surgeon, Danbury Hospital, Danbury, CT. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

_{Do not use this information for medical emergencies - Call 911. This information should not be used for the diagnosis or treatment of any medical condition. A licensed medical practitioner should always be consulted for diagnosis and treatment of any and all medical conditions. Links to other websites do not constitute endorsements and are provided for information only. Any duplication or distribution of this information is strictly prohibited.
Copyright 2011 A.D.A.M., Inc.}