Neurological Disorders: GBS (Guillain Barre Syndrome)
What is this?
GBS (Guillain Barre Syndrome), also called as Acute Inflammatory Demyelinating Polyradiculoneuropathy (AIDP), as the name implies is an acute (rapidly evolving) type of neuropathy (nerve disease).
It is an inflammatory type of disease, means the triggering and progression of the disease process is manly related with the process underlying inflammation.
Inflammation is a process that helps in the defense and healing of the body after it is exposed to infections, other threats and trauma etc. The salient manifestations of inflammation, especially the acute type include, pain, increased local temperature, swelling, reddened discoloration and loss of function of the affected part of the body.
Although the original purpose of the inflammatory process is to help and defend the body but if it is not checked properly it can do more harm than good. Also sometimes the inflammatory process is triggered unnecessarily by body system, and in that case only outcome is the harm to the body and it can result in a diseases process like AIDP.
In the case of GBS, the inflammatory process damages the myelin structure of the nerves. Myelin is an insulation material around certain types of nerves (mainly the large diameter nerve fibers); it enhances the conduction of nerve impulses (electrical signals) along these nerves considerably. When the myelin tissue gets damaged them the conduction slows down and will affect various motor and sensory functions of the limbs and body. Myelin is also present in the brain & spinal cord but it is not affected as it has certain structural differences with the one found along the nerves.
This nerve disease is also called as polyradiculoneuropathy because the myelin damage extends up to the spinal nerve rots as well.
This disease can affect the cranial nerves also. These nerves originate from the brain (a very small portion from the upper spinal cord as well) and control the sensation (general and special like vision, hearing etc) and motor functions of the head, face region. Autonomic nerve fibers are frequently damaged too; these components of the nervous system supply the bowel, bladder, heart, gastrointestinal tract, sexual organs etc.
AIDP can affect almost anybody irrespective of age, gender, race, and ethnicity. Incidence is higher in patients with HIV/AIDS disease.
What triggers it?
As discussed above it is an inflammatory type of disease. It is also considered as an autoimmune disorder because the body’s immune system, instead of protecting paradoxically troubles it. In this case the immune system mounts an inflammatory reaction to the nerves and spinal nerve roots.
A preceding episode of infection is not uncommon; it is usually viral, sometimes bacterial as well. Recent history of vaccination and surgeries are also somehow related with the triggering of this disease.
How does patient present? (Not every patient will have all of these symptoms)
• Symptoms generally start in the legs and ascend upwards
• Tingling sensation (pins & needles)
• Muscle weakness
• Sensory deficits
• Decreased or absent deep tendon reflexes
• Cranial nerve dysfunction; facial droop, eyelid drooping, double vision, difficulty swallowing, speech problems etc
• Bowel/bladder disturbances like incontinence, retention, diarrhea, constipation etc
• Heart ate, blood pressure and temperature abnormalities
• Sexual dysfunction
Although majority of the patients with GBS recover either fully or with reasonable improvement, however some succumb to the disease and some other remain with severe motor disabilities.
Types and/or variants of AIDP
• The typical or classical type
• (AMAN )acute motor axonal neuropathy)
• Acute motor & sensory type
• Autonomic type
• Miller Fischer variant
The classical type presents with ascending type manifestations (stat in the legs then move upwards) and this is the commonest type
AMAN type involves only the motor fibers and this type is more common in China.
Acute motor & sensory type has clinical resemblance to classical type where is pathological relation to AMAN types.
Autonomic type presents with severe autonomic involvement from the beginning.
Miller Fisher variant is also called as descending type of GBS because manifestation begins in the face (cranial nerves) then involves the limbs. Involvement of eye muscles and severe in-coordination is a characteristic feature of this variant.
An EMG/NCS (electromyography and nerve conduction study) is of immense value in clinching the diagnosis. A CSF (cerebrospinal fluid) analysis generally shows elevated protein with increase in only few cells a phenomenon called as albuminocytological dissociation. A nerve biopsy may be rarely necessary. Neuropathy blood tests like ESR, ANA, B2, thyroid tests HIV test etc & MRI of spine are ordered in equivocal cases.
Both the EMG and CSF test may not help much in the very early periods of the disease, so they may have to be repeated.
GBS Patients are treated most often in the following lines;
• Admission to the hospital & stabilization
• Breathing assistance if required (nasal oxygen, ventilator etc)
• Intravenous immunoglobulin or plasmapheresis
• Symptomatic treatment (e.g. gabapentin for nerve pain, numbness etc)
• Physical therapy & occupational therapy as required and tolerated by the patient.
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