(See also Overview of Peripheral Nervous System Disorders Overview of Peripheral Nervous System Disorders The peripheral nervous system refers to parts of the nervous system outside the brain and spinal cord. It includes the cranial nerves and spinal nerves from their origin to their end. The anterior... read more .)
Guillain-Barré syndrome is the most common acquired inflammatory neuropathy. There are several variants. In some variants, demyelination Overview of Demyelinating Disorders Myelin sheaths cover many nerve fibers in the central and peripheral nervous system; they accelerate axonal transmission of neural impulses. Disorders that affect myelin interrupt nerve transmission... read more predominates; other variants affect the axon.
Etiology of GBS
Although the cause of Guillain-Barré syndrome is not fully understood, it is thought to be autoimmune.
In about two thirds of patients, Guillain-Barré syndrome begins 5 days to 3 weeks after a banal infectious disorder, surgery, or vaccination. Infection is the trigger in > 50% of patients; common pathogens include
Herpesviruses Overview of Herpesvirus Infections Eight types of herpesviruses infect humans ( see Table: Herpesviruses That Infect Humans). After initial infection, all herpesviruses remain latent within specific host cells and may subsequently... read more (including cytomegalovirus and Epstein-Barr virus)
A cluster of cases followed the swine flu vaccination program in 1976, but the association was later shown to be spurious, due to ascertainment bias. In some patients, Guillain-Barré syndrome has developed after a Zika virus infection Zika Virus (ZV) Infections The Zika virus is a mosquito-borne flavivirus that is antigenically and structurally similar to the viruses that cause dengue, yellow fever, and West Nile virus. Zika virus infection is typically... read more or after COVID-19 COVID-19 COVID-19 is an acute, sometimes severe, respiratory illness caused by the novel coronavirus SARS-CoV-2. Prevention is by vaccination, infection control precautions (eg, face masks, handwashing... read more .
Adverse effects of immune checkpoint inhibitors include a syndrome that resembles Guillain-Barré syndrome.
If weakness progresses for > 2 months, chronic inflammatory demyelinating polyneuropathy Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) Chronic inflammatory demyelinating polyneuropathy is an immune-mediated polyneuropathy characterized by symmetric weakness of proximal and distal muscles and by progression continuing > 2 months... read more is diagnosed.
Symptoms and Signs of GBS
Flaccid weakness predominates in most patients with Guillain-Barré syndrome; it is always more prominent than sensory abnormalities and may be most prominent proximally. Relatively symmetric weakness with paresthesias usually begins in the legs and progresses to the arms, but it occasionally begins in the arms or head. In 90% of patients, weakness is usually maximal at 3 to 4 weeks. Deep tendon reflexes are lost. Sphincters are usually spared. Weakness remains the same for a variable period of time, typically for a few weeks, then resolves.
Facial and oropharyngeal muscles are weak in > 50% of patients with severe disease. Dehydration and undernutrition may result. Respiratory paralysis severe enough to require endotracheal intubation and mechanical ventilation occurs in 5 to 10%.
A few patients (possibly with a variant form) have significant, life-threatening autonomic dysfunction causing blood pressure fluctuations, inappropriate antidiuretic hormone secretion, cardiac arrhythmias, gastrointestinal stasis, urinary retention, and pupillary changes.
An unusual variant (Fisher variant, or Miller-Fisher syndrome) may cause only ophthalmoparesis, ataxia, and areflexia.
Diagnosis of GBS
Cerebrospinal fluid (CSF) analysis
Diagnosis of Guillain-Barré syndrome is primarily clinical.
Similar acute weakness Weakness Weakness is one of the most common reasons patients present to primary care clinicians. Weakness is loss of muscle strength, although many patients also use the term when they feel generally... read more can result from myasthenia gravis, botulism, poliomyelitis (mainly outside the US), tick paralysis, West Nile virus infection, metabolic neuropathies, and transverse myelitis, but these disorders can usually be distinguished as follows:
Botulism Botulism Botulism is poisoning that is due to Clostridium botulinum toxin and that affects the peripheral nerves. Botulism may occur without infection if toxin is ingested, injected, or inhaled... read more may cause fixed dilated pupils (in 50%) and prominent cranial nerve dysfunction with normal sensation.
West Nile virus causes headache, fever, and asymmetric flaccid paralysis but spares sensation.
Metabolic neuropathies occur with a chronic metabolic disorder.
Transverse myelitis causes pain, weakness, abnormal sensation, and urinary dysfunction.
Tests for infectious disorders and immune dysfunction, including tests for hepatitis and HIV and serum protein electrophoresis, are done.
If Guillain-Barré syndrome is suspected, patients should be admitted to a hospital for electrodiagnostic testing (nerve conduction studies and electromyography), CSF analysis, and monitoring by measuring forced vital capacity every 6 to 8 hours. Initial electrodiagnostic testing detects slow nerve conduction velocities and evidence of segmental demyelination in two thirds of patients; however, normal results, particularly within the first 5 to 7 days, do not exclude the diagnosis and should not delay treatment.
CSF analysis may detect albuminocytologic dissociation (increased protein but normal white blood cell count), but it may not appear for up to 1 week and does not develop in 10% of patients.
Rarely, cervical spinal cord compression—particularly when polyneuropathy coexists (causing or contributing to hyporeflexia) and bulbar involvement is not prominent—may mimic Guillain-Barré syndrome; in such cases, MRI should be done.
Prognosis for GBS
Guillain-Barré syndrome is fatal in < 2%. Most patients improve considerably over a period of months, but about 30% of adults and even more children have some residual weakness at 3 years. Patients with residual defects may require retraining, orthopedic appliances, or surgery.
After initial improvement, 2 to 5% of patients develop chronic inflammatory demyelinating polyneuropathy Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) Chronic inflammatory demyelinating polyneuropathy is an immune-mediated polyneuropathy characterized by symmetric weakness of proximal and distal muscles and by progression continuing > 2 months... read more (CIDP).
Treatment of GBS
Intensive supportive care
IV immune globulin (IVIG) or plasma exchange
Guillain-Barré syndrome is a medical emergency, requiring constant monitoring and support of vital functions, typically in an intensive care unit. Forced vital capacity should be measured frequently so that respiration can be assisted if necessary; if vital capacity is < 15 mL/kg, endotracheal intubation is indicated. Inability to lift the head off the pillow by flexing the neck is another danger sign; it frequently develops simultaneously with phrenic nerve (diaphragm) weakness.
If oral fluid intake is difficult, IV fluids are given as needed to maintain a urine volume of at least 1 to 1.5 L/day. Extremities should be protected from trauma and from the pressure of bed rest.
Heat therapy helps relieve pain, making early physical therapy possible. Immobilization, which may cause ankylosis and contractures, should be avoided. Passive full-range joint movement should be started immediately, and active exercises should be initiated when acute symptoms subside. Low molecular weight heparin (LMWH) helps prevent deep venous thrombosis in bedbound patients. Several randomized trials and meta-analyses have reported that LMWH is more effective than low-dose unfractionated heparin (typically given as 5000 units twice a day) and has a similar risk of bleeding.
Given early, IVIG 2 g/kg over 1 to 2 days or, more slowly, as 400 mg/kg IV once a day for 5 consecutive days is the treatment of choice; it has some benefit up to 1 month from disease onset.
Plasma exchange Plasma exchange Apheresis refers to the process of separating the cellular and soluble components of blood using a machine. Apheresis is often done on donors where whole blood is centrifuged to obtain individual... read more helps when done early; it is used if IVIG is ineffective. Plasma exchange shortens the disease course and hospital stay, and reduces mortality risk and incidence of permanent paralysis. However, it may cause hypotension due to large fluid shifts, and IV access may be difficult or cause complications. Plasma exchange removes any previously administered IVIG, negating its benefits, and so should never be done during or soon after use of IVIG. Waiting at least 2 to 3 days after stopping IVIG is recommended.
Pearls & Pitfalls
Corticosteroids do not improve and may worsen the outcome.
Guillain-Barré syndrome typically begins with an ascending, relatively symmetric flaccid weakness.
Initially, distinguish other disorders that cause similar symptoms (eg, myasthenia gravis, botulism, tick paralysis, West Nile virus infection, metabolic neuropathies, transverse myelitis; outside the US, poliomyelitis) based on history and examination results.
Do electrodiagnostic testing and CSF analysis, even though diagnosis is primarily clinical.
Most patients improve considerably over a period of months, but about 30% of adults and even more children have some residual weakness at 3 year, and 2 to 5% develop chronic inflammatory demyelinating polyneuropathy.
Intensive supportive care is key to recovery.
Try IVIG first, then if it is ineffective, plasma exchange.
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