Following on from yesterday's video, today's post from aboutperipheralneuropathy.blogspot.com (see link below) is the text attached to the video and gives a much more detailed explanation of neuropathy testing and diagnosis. Sadly, many neuropathy patients never get to the MRI, skin biopsy stage of testing because either their doctors feel they have enough information from the patient's own account, or there is pressure from financial authorities not to 'indulge' in very expensive testing procedures. It is true that in many cases, the patient's own experiences, coupled with an obvious cause for their neuropathy (diabetes, HIV, cancer treatment etc) mean that further testing is unnecessary - it's quite clear what the problem is and the treatment is generally not influenced by further extensive testing. An interesting breakdown of neuropathy diagnosis.
Monday, 2 September 2013
Nervous system
Peripheral neuropathy is characterized by damage to nerves of the peripheral nervous system (nerves outside the brain and the spinal cord). It compasses a wide range of disorders.
Diagnosing peripheral neuropathy is a challenge to the medical profession. It is not easy because the symptoms are highly variable. Diagnosis usually involves a thorough neurological examination.
Diagnosis of peripheral neuropathy involves extensive analysis of patient history. This includes patient’s work environment, various symptoms, social habits, exposure to toxins, risk of HIV, history of alcoholism, risk of various infectious diseases and family history of nerve related medical conditions.
Doctors perform tests in order to identify the cause of neuropathic disorder. They conduct tests to determine the extent of nerve damage. Tests are also conducted to determine the type of nerve damage.
Presence of a systemic medical condition (something that is affecting the entire system) is revealed by general physical examination and related tests. Liver dysfunction, diabetes, vitamin deficiencies, kidney dysfunction and signs of abnormal immune system activity are detected by blood test.
Examination of cerebrospinal fluid that surrounds the brain and the spinal cord reveals abnormal antibodies associated with neuropathy. Specialized tests reveal cardiovascular disorders, blood related medical conditions, connective tissue disorders or malignancies.
Motor fiber involvement may be determined by testing muscle strength and by checking for evidence of cramps or fasciculations (muscle twitches). Muscle twitch is a small, local, involuntary muscle contraction and relaxation which is usually visible under the skin.
Sensory nerve damage can be identified by evaluating the patient’s ability to register light touch, pain, vibration, body position and temperature. This evaluation also indicates whether small or large sensory nerve fibers are affected.
Doctors may recommend additional tests based on the results of the neurological examination, patient history, physical examination and any pervious testing or screening. It depends on the patient’s overall condition. Additional tests help to determine the nature and extent of neuropathy.
MRI
Magnetic resonance imaging (MRI) is used to examine muscle size and quality. It can also detect any fatty replacement of muscle tissue. MRI can determine whether a nerve fiber has sustained compression damage.
MRI uses a magnetic field and pulses of radio wave energy. It reveals problems that cannot be seen with other imaging methods. During an MRI test, the area of the body being studied is placed inside a special equipment that contains a strong magnet.
The high-tech MRI equipment creates a strong magnetic field around the body. Radio waves are passed through the body in order to trigger a resonance signal that can be detected at different angles inside the body.
A computer processes this resonance into either a 2D slice or a 3D image of the scanned area. Images from an MRI scan are digital images that can be stored on a computer for further study.
Another advantage of MRI is that the images generated with the help of the test can be reviewed remotely, such as in an operating room or in a clinic. Contrast material is used in some cases to show certain structures more clearly.
NCV
Nerve conduction velocity (NCV) tests are used to precisely measure the degree of damage in larger nerve fibers. They reveal whether symptoms are being caused by degeneration of the axon or the myelin sheath.
Patches known as surface electrodes (similar to those used for ECG) are placed on the skin over nerves at various locations. Each patch gives a mild electrical impulse which stimulates the nerve.
The nerve fiber responds by generating its own electrical impulse. An electrode placed further along the nerve’s pathway measures the speed of impulse transmission along the axon (nerve fiber).
Impulse blockage and slow transmission rates tend to indicate damage to the myelin sheath (a fatty, axon-enwrapping sheath). Reduction in strength of impulses is a sign of axonal degeneration.
To prepare for the test, normal body temperature needs to be maintained. This is because low body temperature slows nerve conduction. It is very important to take appropriate precautions before performing this test on patients with pacemaker or cardiac defribrillator.
During the NCV test, the patient may feel the impulse like an electric shock. It may be uncomfortable to some people. However, there will be no pain after the test is finished. This is the experience of many people on whom this test is performed.
CT scan
CT scan stands for computed tomography scan. It is also known as CAT (computer axial tomography) scan. It is a noninvasive process that employs tomography. Tomography is the process of generating a 2D image of a slice or section through at 3D object (a tomogram).
This medical imaging method is used to produce rapid, clear, 2D images of bones, organs and tissues. CT scan is a painless process. The machine used is knows as CTG scanner. It uses X-rays. X-rays are passed through the body at various angles and are detected by a computerized scanner.
The data that is generated is processed and displayed as cross-sectional images of the internal structure of the body or of a particular organ. These images are also known as slices.
Neurological CT scans detect vascular or bone irregularities, some brain tumors and cysts, encephalitis, herniated disks, spinal stenosis and other disorders. Spinal stenosis is characterized by narrowing of the spinal canal.
EMG
Electromyography (EMG) is a process wherein a fine needle is inserted into a muscle in order to compare the amount of electrical activity present when muscles are at rest and when they contract. EMG helps differentiate between nerve and muscle disorders.
Nerve biopsy
Biopsy is a medical test usually performed by a surgeon or an interventional radiologist. It involves sampling of cells or tissues for examination. It is the removal of tissue form a living object in order to determine the extent or presence of a medical condition.
Nerve biopsy is an invasive procedure involves removing and examining a sample of nerve tissues. Nerve tissues are usually removed from the lower leg. This test can provide valuable information regarding the degree of nerve damage.
Nerve biopsy is an invasive procedure. It is not easy to perform. In some cases, this procedure may itself cause neuropathic side effects. According to experts, nerve biopsy is not always needed for diagnosis.
Skin biopsy
Skin biopsy is a biopsy technique in which doctors remove a thin skin sample and examine nerve fiber endings. This test offers some unique advantages over NCV tests and nerve biopsy.
Unlike NCV, skin biopsy reveals damage present in small fibers. Skin biopsy is less invasive than nerve biopsy. It is also easier to perform. Skin biopsy has lesser side effects than nerve biopsy.
The above-mentioned techniques help doctors diagnose peripheral neuropathy effectively. Right diagnosis enables them to work for improvement in the overall quality of the patient’s life.
Doctors can work with patients affected by peripheralneuropathy and add value to their overall well-being. For this to be possible, patients should keep up their appointments with their doctor. Peripheral neuropathy should not be neglected.
http://aboutperipheralneuropathy.blogspot.com/2013/09/how-to-diagnose-peripheral-neuropathy.html
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