Pulmonary Medicine

Neuromuscular Disorders Affecting the Thorax: Guillain-Barre Syndrome

What every physician needs to know:

Guillain-Barre syndrome (GBS), or acute idiopathic polyneuritis, is characterized by ascending symmetric paralysis. Respiratory involvement may be absent, or it may be severe enough to necessitate mechanical ventilation. Seventy percent of cases are preceded by viral or bacterial infection. The incidence of GBS worldwide ranges from 1.1 per 100,000 persons per year to1.8 per 100,000 persons per year. Among those older than age fifty, the incidence increases to between 1.7 and 3.3 per 100,000 persons per year.

Classification

Not applicable.

Are you sure the patient has Guillain-Barre syndrome? What should you expect to find?

Clinical findings in GBS include weakness associated with absent tendon reflexes and autonomic dysfunction form mild paresis to complete paralysis. Half of patients reach their maximum level of weakness within two weeks of onset, and 80 percent do so within four weeks. Ten percent of patients may have weakness beginning in the upper extremities, rather than the classic ascending paralysis. Facial (in 60%), oropharyngeal (in 50%), or ocular (in 15%) involvement may occur. The presence of sensory loss is variable, occurring in 40-70 percent of patients; parasthesias occasionally accompany the sensory findings.

Nasal voice (because of palatal incontinence), abnormal gag reflex, dysarthria, or inability to sip water without coughing are additional findings. Severe back pain may be noted, and autonomic dysfunction, observed in 65 percent of patients, is evident as cardiac arrhythmias, blood pressure liability, gastrointestinal dysfunction, pupillary dysfunction, and urinary retention. Fifteen to thirty percent of patients develop respiratory failure requiring mechanical ventilation, the average duration of which is 50-55 days, with most requiring tracheostomy.

Diagnostic criteria include features required for making the diagnosis and those supportive of the diagnosis. Features required for the diagnosis are progressive weakness of more than one limb, accompanied by areflexia. Weakness may involve only the lower extremities, with hyporeflexia noted elsewhere. Features supportive of the diagnosis are symptom progression over days or weeks, relative symmetry of findings, mild sensory findings, autonomic dysfunction, and absence of fever at the time of presentation. An elevation in cerebrospinal fluid (CSF) protein and characteristic electrodiagnostic studies support the clinical findings. Antibody testing may also be useful.

An alternative diagnosis should be considered when the CSF cell count exceeds 10/mm3, a sensory level is present, asymmetric weakness persists, or severe, persistent bowel or bladder dysfunction is noted.

Beware: there are other diseases that mimic Guillain-Barre syndrome.

The neurologic disorders that may be confused with GBS include vasculitis with mononeuritis multiplex, Lyme disease, arsenic poisoning, tick paralysis, porphyria, sarcoidosis, leptomeningeal disease, paraneoplastic disease, critical illness myopathy/neuropathy, chronic inflammatory demyelinating polyneuropathy, spinal cord compression, acute transverse myelitis, myasthenia gravis, Lambert-Eaton myasthenic syndrome, botulism, and polymyositis.

How and/or why did the patient develop Guillain-Barre syndrome?

The etiology of GBS is unknown. Risk factors include: viral illnesses, including cytomegalovirus and Epstein-Barr virus infections; infection with Mycoplasma pneumoniae or Campylobacter jejuni; influenza vaccination; recent surgery; and lymphoma.

GBS may be an autoimmune disease, with an aberrant immune response directed against bacterial lipopolysaccharides and epitopes similar to the myelin sheath or Schwann cell basement membrane. Possible links between vaccinations and GBS have been proposed although the evidence is weak.

Which individuals are at greatest risk of developing Guillain-Barre syndrome?

Not applicable.

What laboratory studies should you order to help make the diagnosis, and how should you interpret the results?

GBS is a clinical diagnosis that is supported by additional diagnostic studies, including examination of CSF and electromyography (EMG) and nerve conduction studies. The CSF is characterized by elevated protein and few cells--so-called albumino-cytologic dissociation--which is found in 90 percent of patients after one week of symptoms.

Testing for antibodies directed at a ganglioside component of nerve (anti-GQ1b) may be used to distinguish Miller-Fisher syndrome, a GBS variant, since 85 percent of patients with Miller-Fisher syndrome have anti-GQ1b antibodies.

What imaging studies will be helpful in making or excluding the diagnosis of Guillain-Barre syndrome?

Not applicable.

What non-invasive pulmonary diagnostic studies will be helpful in making or excluding the diagnosis of Guillain-Barre syndrome?

Not applicable.

What diagnostic procedures will be helpful in making or excluding the diagnosis of Guillain-Barre syndrome?

Not applicable.

What pathology/cytology/genetic studies will be helpful in making or excluding the diagnosis of Guillain-Barre syndrome?

Not applicable.

If you decide the patient has Guillain-Barre syndrome, how should the patient be managed?

Consideration should be given to three general areas: supportive care, therapy directed at the underlying disease process, and emergency management.

Supportive Care

Respiratory management focuses on avoiding pulmonary complications and providing timely implementation of mechanical ventilation. Neurophysiologic testing helps predict the need for mechanical ventilation, as a demyelinating pattern is associated with a greater need for intubation than is an axonal pattern or equivocal findings. Serial vital capacity measurements may also be useful in predicting the need for mechanical ventilation, as a VC of 12-15 mg/kg is a sign of imminent respiratory failure. VC averages 33 percent of predicted at the time of intubation.

Other predictors of the need for intubation include fewer than seven days between symptom onset and hospitalization, an inability to lift the head, bulbar dysfunction, and the presence of anti-GQ1b antibodies. Tracheostomy should be considered after two weeks if no improvement in pulmonary function is noted. During the recovery phase, weaning trials should be considered when the VC exceeds 8-10 ml/kg, adequate oxygenation is achieved using an FiO2 less than 40 percent, and the patient is able to double the minute ventilation and generate a negative inspiratory force greater than -40 cmH2O.

Autonomic dysfunction warrants close monitoring.

Cardiovascular management includes stabilization of blood pressure (sometimes necessitating insertion of an arterial line), treatment of hypotension with intravenous fluids or pressors (e.g., phenylephrine), treatment of hypertension (e.g., using labetalol, esmolol, or nitroprusside), and monitoring for and correction of arrhythmias. Sinus tachycardia, which is common in GBS, requires no treatment.

Bowel and bladder function must be monitored closely.

Pain control is an important aspect of management. Opiate use should be limited, although gabapentin, carbamazepine, and nonsteroidal anti-inflammatory drugs may be helpful. Use of DVT prophylaxis is critical.

Incorporation of rehabilitation services early in the patient's course is encouraged.

Therapy Directed at the Underlying Disease Process

Plasmapheresis plays a central role in management of GBS. Plasmapheresis is most effective if it is started within seven days of symptom onset; however, improvement can be demonstrated with initiation of plasmapheresis started within thirty days. Plasmapheresis (with albumin or fresh frozen plasma) given at a dose of 250 mL/kg every two days for a total of five treatments produces short-term benefits, promotes early motor recovery and ambulation, and results in a decrease in the need for mechanical ventilation. Ten percent of patients may relapse after plasmapheresis because of antibody rebound.

Use of intravenous immunoglobulin (IVIG) is preferable to plasma exchange, as it is easier to administer. IVIG (0.4 g/kg/day for five days), begun within two weeks of disease onset, may be as effective as plasmapheresis. Contraindications to the use of IVIG include low serum IgA level, uncontrolled hypertension, and a hyperosmolar state. No benefit has been demonstrated to giving IVIG following plasmapheresis compared with administration of each therapy alone.

Administration of corticosteroids alone has not been demonstrated to be of benefit. While use of corticosteroids may slow recovery, administration of corticosteroids in addition to IVIG may hasten recovery, although no long-term data are available.

For particularly refractory cases, use of interferon-beta may be beneficial.

Emergency Management

For respiratory emergencies, guidelines for intubation include a VC less than 12-15 mg/kg, hypoxemia (PaO2 less than 70 mmHg or PaO2/FiO2 greater than 300 mmHg using an FiO2 of 1), hypercapnia, or an inability to clear oral secretions. Succinylcholine should be avoided during intubation, as its use in this population has been associated with development of rapid hyperkalemia and subsequent life-threatening arrythmias. Delayed intubation in those with bulbar dysfunction increases the risk of early pneumonia.

For cardiac emergencies, observation for arrhythmias with intubation and suctioning to address autonomic dysfunction is important. Tachyarrhythmias, bradyarrhythmias, or asystole may occur.

What is the prognosis for patients managed in recommended ways?

The prognosis for recovery from GBS is usually good.. Common complications include pneumonia, recurrent aspiration, and pulmonary embolism. Eighty-five percent of patients have residual neurologic sequelae. Mortality decreased from 15 percent in the 1970s to under 4 percent by 1980.

A poor prognosis is associated with older age, lower (less than 20% of normal) mean compound muscle action potential amplitudes during distal nerve stimulation, need for ventilatory support, and rapid progression to severe weakness (less than one week).

What other considerations exist for patients with Guillain-Barre syndrome?

None.

What’s the evidence?

Orlikowski, D, Sharshar, T, Porcher, R, Annane, D, Raphael, JC, Claire, B. "Prognosis and risk factors of early onset pneumonia in ventilated patients with Guillain-Barre syndrome". Intensive Care Med. vol. 32. 2006. pp. 1962-69.

(Eighty-one patients who required intubation for GBS were evaluated. Mean vital capacity was 33+11% predicted at the time of intubation. A significant portion of the patients developed early-onset pneumonia, which may have been associated with aspiration. Delayed intubation may increase the risk of early onset pneumonia.)

Chevrolet, JC, Deleamont, P. "Repeated vital capacity measurements as predictive parameters for mechanical ventilation need and weaning success in the Guillain-Barre syndrome". Am Rev Respir Dis. vol. 144. 1991. pp. 814-8.

(In five patients with GBS who required intubation, vital capacity decreased in the forty-eight hours preceding intubation. Average VC at the time of intubation was 15.2+3.7 ml/kg. Vital capacity was stable and greater than 40ml/kg in those who did not require intubation.)

"Plasmapheresis and acute Guillain-Barre syndrome". Neurology. vol. 35. 1985. pp. 1096-1104.

(The use of plasmapheresis was studied in 245 patients with acute GBS. Plasmapheresis was shown to improve outcomes at four weeks and to decrease time to independent walking and improve outcome at six months. Treatment was particularly effective when given within seven days of symptom onset and in those who required mechanical ventilation.)

van der Meche, FGA, Schmitz, PI. "A randomized trial comparing intravenous immune globulin and plasma exchange in Guillain-Barre syndrome". N Engl J Med. vol. 326. 1993. pp. 1123-1129.

(Patients with acute GBS with associated inability to walk were assigned to receive either five plasma exchanges or five doses of IVIG. IVIG led to a significant improvement in strength and a trend toward decreased time to improvement compared to plasmapheresis. There were fewer side effects in the IVIG group, suggesting that IVIG is at least as effective or better than plasma exchange.)

Ropper, AH, Kehne, SM. "Guillain-Barre syndrome: management of respiratory failure". Neurology. vol. 35. 1985. pp. 1662.

(This paper reported on nineteen of thirty-eight patients with GBS who were treated with mechanical ventilation for vital capacity below 12-15 ml/kg, hypoxemia, or fatigue. When VC was greater than 8-10 ml/kg, mechanical ventilation was discontinued. Twelve patients required tracheostomy, and mechanical ventilation was required for an average of forty-nine days.)

Lawn, ND, Fletcher, DD, Henderson, RD, Wolter, TD, Wijdicks, EF. "Anticipating mechanical ventilation in Guillain-Barre syndrome". Arch Neurol. vol. 58. 2001. pp. 893-8.

(This retrospective study examined 114 patients with GBS admitted to the intensive care unit. Progression to mechanical ventilation was likely to occur in patients with rapid disease progression, bulbar dysfunction, bilateral facial weakness, or dysautonomia. Vital capacity less than 20 ml/kg and maximal inspiratory pressures less than 30 cm H2O were associated with respiratory failure. There were no clinical predictors to anticipate the progression to respiratory failure.)
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