Acute Motor Axonal Neuropathy, Diagnosis, Treatment

Acute Motor Axonal Neuropathy
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Acute Motor Axonal Neuropathy/Guillain–Barré syndrome (GBS) is a rapid-onset disorder in which the body’s immune system attacks part of the peripheral nervous system & muscle weakness caused by the immune system damaging the peripheral nervous system. The initial symptoms are typically changes in sensation or pain along with muscle weakness, beginning in the feet and hands. This often spreads to the arms and upper body, with both sides being involved. The symptoms develop over hours to a few weeks. During the acute phase, the disorder can be life-threatening, with about 15% developing weakness of the breathing muscles requiring mechanical ventilation. Some are affected by changes in the function of the autonomic nervous system, which can lead to dangerous abnormalities in heart rate and blood pressure. Guillain-Barre syndrome is also known as polyneuropathy, which is a disease that involves several nerves.

Another name of Guillain–Barré syndrome

  • acute inflammatory demyelinating polyradiculoneuropathy
  • acute motor axonal neuropathy
  • acute motor neuropathy with conduction block
  • acute motor-sensory axonal neuropathy

Guillain-Barré Syndrome or Acute Polyneuropathy is a disorder which affects the peripheral nervous system.

Types of Guillain–Barré syndrome

Once thought to be a single disorder, Guillain-Barre syndrome is now known to occur in several forms. The main types are:

  • Acute inflammatory demyelinating polyradiculoneuropathy (AIDP), the most common form in the U.S. The most common sign of AIDP is muscle weakness that starts in the lower part of your body and spreads upward.
  • Miller Fisher syndrome (MFS), in which paralysis starts in the eyes. MFS is also associated with unsteady gait. MFS occurs in about 5 percent of people with Guillain-Barre syndrome in the U.S. but is more common in Asia.
  • Acute motor axonal neuropathy (AMAN) and acute motor-sensory axonal neuropathy (AMSAN) are less common in the U.S. But AMAN and AMSAN are more frequent in China, Japan and Mexico.
  • Acute Motor Sensory Axonal Neuropathy: This is similar to motor axonal neuropathy but in this form also affected are the sensory nerves.
  • Acute Panautonomic Neuropathy: This is rarest form of GBS. It sometimes occurs with associated encephalopathy. Since there is cardiovascular involvement with this form of GBS, it has a high mortality rate. Some symptoms of this form of GBS are dysphagia, constipation alternating with diarrhea, dry itchy skin, etc.
  • Bickerstaff’s Brainstem Encephalitis: In this form of GBS, symptoms involve acute onset of ophthalmoplegia, ataxia, altered consciousness, and increased reflexes. It can also be relapsing-remitting.

Clinical subtypes of Guillain–Barré syndrome

A number of subtypes of Guillain–Barré syndrome are recognized.Despite this, many people have overlapping symptoms that can make the classification difficult in individual cases.All types have partial forms. For instance, some people experience only isolated eye-movement or coordination problems; these are thought to be a subtype of Miller Fisher syndrome and have similar antiganglioside antibody patterns.

Type Symptoms Population affected Nerve conduction studies Antiganglioside antibodies
Acute inflammatory demyelinating polyneuropathy (AIDP) Sensory symptoms and muscle weakness, often with cranial nerve weakness and autonomic involvement Most common in Europe and North America Demyelinating polyneuropathy No clear association
Acute motor axonal neuropathy (AMAN) Isolated muscle weakness without sensory symptoms in less than 10%; cranial nerve involvement uncommon Rare in Europe and North America, substantial proportion (30-65%) in Asia and Central and South America; sometimes called “Chinese paralytic syndrome” Axonal polyneuropathy, normal sensory action potential GM1a/b, GD1a & GalNac-GD1a
Acute motor and sensory axonal neuropathy (AMSAN) Severe muscle weakness similar to AMAN but with sensory loss Axonal polyneuropathy, reduced or absent sensory action potential GM1, GD1a
Pharyngeal-cervical-brachial variant Weakness particularly of the throat muscles, and face, neck, and shoulder muscles Generally normal, sometimes axonal neuropathy in arms Mostly GT1a, occasionally GQ1b, rarely GD1a
Miller Fisher syndrome Ataxia, eye muscle weakness, areflexia but usually no limb weakness This variant occurs more commonly in men than in women (2:1 ratio). Cases typically occur in the spring and the average age of occurrence is 43 years old. Generally normal, sometimes discrete changes in sensory conduction or H-reflex detected GQ1b, GT1a
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Causes of Guillain–Barré syndrome

Acute Motor Axonal Neuropathy

  • A viral infection, such as herpes, cytomegalovirus, or Epstein-Barr virus is the cause of over two-thirds of the new cases each year.
  • It’s uncommon – Guillain-Barre Syndrome is pretty rare, affecting only 1 or 2 people per 100,000.
  • It’s a serious autoimmune disorder. According to the National Library of Medicine, Guillain-Barre Syndrome is a serious disorder that occurs when the body’s immune system mistakenly attacks part of the nervous system.
  • It results in muscle weakness – The disorder causes inflammation in the body that creates weakness and sometimes even paralysis.
  • Much is unknown – The causes of Guillain-Barre Syndrome are widely unknown. Many times Guillain-Barre Syndrome symptoms will follow a minor infection, such as a lung or gastrointestinal infection.
  • There is no cure – So far, scientists have not found a cure for Guillain-Barre Syndrome, although many treatment options are available to handle complications and speed up recovery.
  • The cause of the disease is unknown – Many speculate that this is an immune-system disorder. Symptoms often begin 5 days to 3 weeks after a viral infection, immunization, or surgery. The disease affects peripheral nerves, nerve roots, and cranial nerves. Evaluation of the peripheral nerves reveals sections of the nerve with demyelination. Under microscopic exam, the nerve tissue is infiltrated with certain types of white blood cells.
  • Fluoroquinolones -The Fluoroquinolones have been responsible for triggering many different disease states, including Neuropathies from other causes, and be sure to read our page on how Fluoroquinolones Contribute to Autoimmune Disease to see how other diseases are often triggered by these antibiotics. These dangerous drugs accomplish their damage through multiple methods of action, including causing Mitochondrial Damage, DNA Damage to cells, the binding of and excretion of certain nutrients,
  • GBS, unlike multiple sclerosis or amyotrophic lateral sclerosis, is a peripheral nerve ailment and does not cause injury to the brain or the spinal cord.
  • This syndrome causes the destruction, removal, or loss of the myelin sheath of a nerve. Myelin is the substance of the cell membrane that coils to form the myelin sheath. The myelin sheath serves as an electrical insulator to nerve fibers
  • In 1977, there were over 500 cases of Guillain-Barre syndrome associated with a United States flu vaccination program. The cause of this outbreak was never discovered.
  • 5-10% of new cases will occur up to 4 weeks after surgery.

Symptoms of Guillain–Barré syndrome

Symptoms of GBS, including weakness, instability, and pain, typically start in the lower body and move upwards.

Symptoms and other complications include

Diagnosis of Guillain–Barré syndrome

After a physical exam, a physician may recommend the following tests:

  • Blood tests and urine tests These are done to check for infections and other problems.
  • Nerve conduction exam – Electrodes are taped to the skin, and the speed of nerve signal conduction is tested by passing small shocks along the nerves through the skin. In GBS, the signals travel more slowly along the nerves.
  • Electromyography (EMG) Thin, needle-like electrodes are used to test the nerve function within muscle fibers.
  • Spinal tap, also known as a lumbar puncture A sample of cerebrospinal fluid (CSF) is removed from the spinal canal and tested in a laboratory for specific signs of the disease. More protein is present in the CSF of people with GBS. Your cerebrospinal fluid is then tested to detect protein levels. People with Guillain-Barré typically have higher-than-normal levels of protein in their cerebrospinal fluid. This test is also referred to as a lumbar puncture.
  • Electromyogram (EMG) This test measures the electrical activity of a muscle or a group of muscles. An EMG can find abnormal electrical muscle activity caused by diseases and conditions that affect the nerves and muscles.
  • Pulmonary function testThis is a breathing test done by a respiratory therapist. It shows your child’s lung capacity and how strong his or her respiratory muscles are. This test is often used to decide if a child needs breathing support with a ventilator.
  • Electrolyte levels
  • Liver function tests (LFTs)
  • Creatine phosphokinase (CPK) level
  • Erythrocyte sedimentation rate (ESR)
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Biochemical screening can also be conducted and would include the following studies:

Needle EMG and nerve conduction studies

  • Nerve conduction slowing
  • Prolongation of the distal latencies
  • Prolongation of the F-waves
  • Conduction block or dispersion of responses – Evidence frequently demonstrated at sites of natural nerve compressionWeak muscles showing reduced recruitment: Demonstrated with needle examination.

Associate disease tests

Treatment of Guillain–Barré syndrome

  • Plasma exchange (plasmapheresis). The liquid portion of part of your blood (plasma) is removed and separated from your blood cells. The blood cells are then put back into your body, which manufactures more plasma to make up for what was removed. Plasmapheresis may work by ridding plasma of certain antibodies that contribute to the immune system’s attack on the peripheral nerves.
  • Immunoglobulin therapy. Immunoglobulin containing healthy antibodies from blood donors is given through a vein (intravenously). High doses of immunoglobulin can block the damaging antibodies that may contribute to Guillain-Barre syndrome.
  • Intensive care unit – Admission to the intensive care unit (ICU) should be considered for all patients with labile dysautonomia, a forced vital capacity of less than 20 mL/kg, or severe bulbar palsy.Any patients exhibiting clinical signs of respiratory compromise to any degree also should be admitted to an ICU. 

Competent intensive care includes the following features

  • Respiratory therapy
  • Cardiac monitoring
  • Safe nutritional supplementation
  • Monitoring for infectious complications (eg, pneumonia, urinary tract infections, septicemia)Subcutaneous unfractionated or low ̶ molecular-weight heparin (LMWH) and thromboguards are often used in the treatment of immobile patients to prevent lower-extremity deep venous thrombosis (DVT) and consequent pulmonary embolism (PE).
  • Immunomodulation – Immunomodulatory treatment in GBS has been used to hasten recovery. Intravenous immunoglobulin (IVIG) and plasma exchange have proved equally effective.

Physical, occupational & speech therapy of Guillain–Barré syndrome

In I.V.I.G, immunoglobulins are given intravenously which shows a positive impact on the speed of recovery. But it has been shown to be less effective than plasmapheresis.

Further medical management can be done according to the symptoms and the complications :
a. Supportive Care

  • ICU monitoring
  • Basic medical management often determines mortality and morbidity.

b. Ventilatory Support

  • Atelectasis leads to hypoxia.
  • Hyper-carbia later finding; arterial blood cases may be misleading.
  • Vidal capacity, tidal volume and negative inspiratory force are best indicators of diaphragmatic function.
  • Progressive decline of these functionsindicatese an impending need or ventilatory assistance.
  • Mechanical ventilation usually required if VC drops below about 14 ml/kg; ultimate risk depending on age, presence of accompanying lung disease, aspiration risk, and assessment of respiratory muscle fatigue
  • Atelectasis treated initially by incentive spirometry, frequent suctioning, and chest physiotherapy to mobilize secretions.
  • Intubation may be necessary in patients with substantial oro-pharyngeal dysfunction to prevent aspiration.
  • Tracheostomy may be needed in patients intubated for 2 weeks who do not show improvement.

c. Autonomic dysfunction

d. Nosocomial infections usually involve pulmonary and urinary tracts.

  • Occasionally central venous catheters become infected.
  • Antibiotic therapy should be reserved for those patients showing clinical infection rather than colonization of fluid or sputum specimens.

e. Venous thrombosis due to immobilization poses great risk of thromboembolism.

Physiotherapy of Guillain–Barré syndrome

Aims of the treatment are to

  • Respiratory therapy
  • Maintain clear airways
  • Prevent lung infection
  • Maintain anatomical joint range
  • Support joint in functional position to minimize damage or deformit
  • Prevention of pressure sores
  • Maintain peripheral circulatio
  • Provide psychological support for the patient and relatives. 1. Maintenance of clear airway & prevention of lung infection
  1.  Respiratory therapy
  • Respiratory therapy
  • The patients breathing will be assisted by intermittent positive pressure ventilation (IPPV) via a cuffed tracheostomy tube.
  • Posturally drain areas of lung tissues, 2-hourly turning into supine or side lying positions.
  • A suction catheter is used to remove secretions from respective passage until the cough reflex re-appears.
  • Manual techniques like vibration with/ without over pressure.
  • 2-4 litre anesthetic bag can be used to enhance chest expansion. Therefore , 2 people are necessary for this technique, one to squeeze the bag and another to apply chest manipulation.
  • Rib springing to stimulate cough.
  • After the removal of ventilator and adequate expansion, effective coughing must be taught to the patient
  • As neurons recover, active assisted or active breathing exercises may commence with good amount of relaxing time.
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2. To maintain normal joint movement 

Gentle passive movements through full ROM at least three times a day especially at hip , shoulder, wrist, ankle, feet.

3.Support joints

Use of light splints(eg. using PLASTAZOTE) may be required for the following purpose listed below
  • Support the peripheral joints in comfortable and functional position during flaccid paralysis.
  • To prevent abnormal movements.
  • To stabilize patients using sandbags, pillows. 4. Prevention of pressure sores :
2- hourly change in patients position from supine to side lying. If the sores have developed then UVR or ice cube massage to enhance healing. 5. Maintenance of circulation
  • Passive movements
  • Effleurage massage to lower limbs.

Relief of pain

  • Transcutaneous electrical nerve stimulation
  • Massage with passive ROM
  • Patient can demonstrate increased sensitivity to light touch, a cradle can be used to keep the bed sheet away from the skin.
  • Low pressure wrapping or snug fitting garments can provide a way to avoid light touch.
  • Reassurance and explanation of what to expect can help in alleviation of anxiety that could compound the pain.
Exercises to be prescribed to the patient should be started with low repetitions and short, frequent bouts of exercises matched to the patients muscular strength. According to Bensman (1970), the following four guidelines are to be followed for prescription of exercises
  • Use short periods of non-fatiguing exercises matched to the patients strength.
  • Progression of the exercise should be done only if the patient improves or if there is no deterioration in status after a week.
  • Return the patient to bed rest if a decrease in muscle strength or function occurs
  • The objective should be directed towards not only at improving function but also in improving strength.

Complications of Guillain–Barré syndrome

Guillain-Barre syndrome affects your nerves. Because nerves control your movements and body functions, people with Guillain-Barre may experience

  • Breathing difficulties The weakness or paralysis can spread to the muscles that control your breathing, a potentially fatal complication. Up to 30 percent of people with Guillain-Barre syndrome need temporary help from a machine to breathe when they’re hospitalized for treatment.
  • Residual numbness or other sensations Most people with Guillain-Barre syndrome recover completely or have only minor, residual weakness, numbness or tingling.
  • Heart and blood pressure problems Blood pressure fluctuations and irregular heart rhythms (cardiac arrhythmias) are common side effects of Guillain-Barre syndrome.
  • Pain – Up to half of people with Guillain-Barre syndrome experience severe nerve pain, which may be eased with medication.
  • Blood clots – People who are immobile due to Guillain-Barre syndrome are at risk of developing blood clots. Until you’re able to walk independently, taking blood thinners and wearing support stockings may be recommended.
  • Residual numbness or other sensations – Most people recover completely or have only minor, residual weakness, numbness or tingling.
  • Heart and blood pressure problems Blood pressure fluctuations and irregular heart rhythms (cardiac arrhythmias) are common side effects of Guillain-Barre syndrome.
  • Bowel and bladder function problems Sluggish bowel function and urine retention may result from Guillain-Barre syndrome.
  • Blood clotsn –  People who are immobile due to this illness are at risk of developing blood clots. Wear support stockings and take blood thinners.
  • Pressure sores Being immobile also puts you at risk of developing bedsores (pressure sores). Frequent repositioning may help avoid this problem.
  • Relapse – Around 3 percent of people with Guillain-Barre syndrome experience a relapse.


Acute Motor Axonal Neuropathy


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