The diagnostic procedures for discovering ALS can be complicated and it can take a while until a definitive diagnosis is finally reached. As the disease shares many characteristics with other diseases and health conditions, a wide range of tests are often needed before an ALS diagnosis can be confirmed.
These tests may include an initial physical exam by a neurologist, urine and blood tests, scans such as an MRI, and various muscle and nerve tests.
Obviously, this can mean a prolonged period of investigation that is stressful for the individual during the time that they wait to find out what is wrong with them.
One test that is regularly used when ALS is suspected is a muscle biopsy, which is more invasive than some of the other tests as it involves the surgical removal of tissue from the patient.
As with many of the tests that may be carried out by medical staff during an investigation of this type, the biopsy is not used to identify ALS itself but is instead used to rule out other conditions. The biopsy, however, can also be used later on as a way of monitoring the progression of the disease.
Here we take a look at what an ALS muscle biopsy involves, why it is used, how it is carried out and what physicians can discover from the results.
A muscle biopsy involves removing a small amount of muscle tissue (usually from the upper arm or upper leg) which is then analyzed under lab conditions to look for cell damage.
Whilst medical staff can look for potential nerve damage which may be a sign of ALS, a lot will be learned in relation to the results obtained from the other diagnostic tests.
Once an official diagnosis has been made, further biopsies might be useful to look at the progression of the disease.
Although relatively invasive, a muscle biopsy is a fairly straightforward and quick surgical process. In the first instance, the area that is going to be investigated will have a local anesthetic administered to numb the muscle. If carried out properly, the patient should not feel any pain and the wound is eventually closed using stitches or surgical glue.
The physician will use either an area in the bicep or the upper thigh to take the sample which will then be send to a laboratory for examination. The process involves making a one or two-inch incision and then taking as many as five, tiny pieces of muscle tissue.
Once the ALS muscle biopsy has been performed, patients are advised not to overly use the affected limb for about a day. There should generally be little in the way of pain. In some circumstances, off the shelf pain medications can be used to reduce any discomfort and the usual standards of wound care such as keeping the area of incision and the dressing clean will apply.
An ALS muscle biopsy gives physicians a chance to take a closer look at what is happening in the patient’s body. The muscle tissue is stained to make it more visible and then placed under a microscope. This will show the extent of any damage that has occurred and may indicate that the patient may have ALS.
The medical staff will look for damaged nerve cells and count them. They may be able to distinguish between different types of ALS. In essence, the investigation will look for some tell-tale signs. For example, in an ALS muscle biopsy, certain things will be present such as shrinkage. In a healthy nerve, there will be web-like tendrils much like a tree. With ALS, the nerves might be clumped together or seem to be withering.
This kind of biopsy may also be used over time to determine the extent and progress of the disease.
Investigations will look for a couple of things:
A muscle biopsy is just a small part of the overall process of diagnosing ALS and is only one tool that can be used to help discover if an individual has the disease or not.
Whilst it is somewhat invasive compared to other tests, it does give medical staff the opportunity to see what exactly is happening with individual muscle cells.