Neurocritical Care

23. Autonomic Failure in Guillain-Barr Syndrome

A 73-year-old man was admitted with progressive weakness and inability to stand unassisted. This was noticed three weeks after a mundane respiratory infection that was briefly treated with antibiotics. The patient started with tingling in all of his extremities followed a day later by rapid onset of weakness for 4 days. Initially, he had no swallowing difficulties, double vision, or shortness of breath; but he was more short-winded and could not swallow liquids well.

On admission, he had a flaccid quadriplegia with generalized areflexia, but also had marked tachypnea that required intubation and mechanical ventilation. On examination, there is a marked bifacial diplegia with limited eye movements. Pupils are sluggish in light responsiveness. He is not overbreathing the ventilator and has a weak cough with tracheal suctioning. There is a flaccid quadriplegia with absent reflexes throughout. The patient is started on intravenous immunoglobulin but, on the fourth day after admission, he starts to develop marked blood pressure fluctuations, and an arterial line is placed. At some point, his systolic blood pressure is measured at 240 mmHg and then suddenly drops to 70 mmHg, which requires a Trendelenburg position. During the following days, these blood pressure fluctuations remain, often with episodes of hypertensive surges. The nursing staff is quite concerned with these readings and would like to have more strict orders and blood pressure goals.

What do you do now?

The management of a patient with a severe Guillain-Barré syndrome (GBS) is not straightforward. It is not just providing intravenous immunoglobulin or plasma exchange, but also adequate supportive ICU care. Any physician should anticipate that patients with GBS are rapidly at risk for ventilator-associated pneumonia, urinary tract infection and sepsis, decubitus ulcers, and gastrointestinal hemorrhages due to the stress of mechanical ventilation. Deep venous thrombosis will need to be aggressively prevented with intermittent pneumatic compression devices plus subcutaneous heparin injections (Table 23.1).

The most concerning part of management is the treatment of acute autonomic failure, usually observed in the more severe cases. Dysautonomia in GBS is manifested by blood pressure fluctuations, cardiac arrhythmias, bladder dysfunction, gastrointestinal dysfunction, bronchial smooth muscle dysfunction, and exaggerated drug responses. Most commonly, as exemplified by our patient, the issue at hand is treatment of blood pressure fluctuations. Paroxysmal or sustained hypertension is seen in about one in four patients with a rapid onset of GBS. Systolic blood pressures can become substantially elevated and reach values that could not only challenge ventricular function, but could even predispose the patient to develop posterior reversible encephalopathy syndrome. (Unexpected new onset seizures or marked visual disturbances in a patient with GBS should prompt an MRI scan to look for its characteristic vasogenic edema.)

TABLE 23.1 Early Management of Guillain-Barr Syndrome

IVIG (0.4 g/kg for 5 consecutive days)*

PLEX (5 plasma volumes in 10 days)*

Prevent early complications

    Subcutaneous heparin 5,000 U 3 × day

    PPI for GI protection

    Decubitus protection (special beds)

    NG tube feeding, consider early PEG in intubated patients, watch for ileus

    Tracheostomy in severely affected patients

Blood pressure fluctuation and cardiac arrhythmias

    Low doses of IV morphine.

    Labetalol, clonidine, or nicardipine

    Avoid bradycardia with suctioning

    Consider pacemaker

* One course of treatment is typical. Using combinations (PLEX after IVIG or IVIG after PLEX) has not been proven to change outcome, but we have anecdotal experience of improvement with such a combination. A second course of IVIG can also be considered.

PLEX = Plasma exchange; IVIG = intravenous immunoglobulin; PPI = proton pump inhibitors; PEG = percutaneous gastrostomy; GI = gastrointestinal; NG = nasogastric.

Why these blood pressure fluctuations occur is not entirely known, but a baroreflex abnormality has been postulated. Baroreceptor sensitivity might be altered as a result of vagal nerve demyelination and because sympathetic nerves have less myelin, there is a sympathetic overdrive. Dysfunction of afferent input from atrial stretch receptors could also play a role in the origin of these blood pressure surges.

These blood pressure elevations would require treatment, but another concern is that treatment might lead to a marked hypotension. This could be due to exaggerated drug sensitivity in GBS, but this phenomenon, although well known, is not adequately understood. Drugs such as clonidine, sodium nitroprusside, or a calcium channel blocker such as nicardipine may be helpful to treat severe hypertension, but in our experience, simply controlling these responses with multiple doses of IV morphine is just as effective and perhaps safer with less hypotension.

Many patients with GBS have a baseline sinus tachycardia as another manifestation of increased sympathetic output. In addition, patients may develop so-called vagal spells, typically after tracheal suctioning. These bradycardic spells may be so severe that they can lead to a brief asystole. A pacemaker may be considered if these episodes are symptomatic and recurrent. In some patients, atrioventricular block or other more benign arrhythmias (e.g., bigeminy) become apparent.

Bronchial function is also likely impaired in Guillain-Barré syndrome, because bronchoconstriction and bronchodilatation are under the control of vagal and sympathetic innervation. There is some evidence that impaired bronchoconstriction and dilation due to abnormal innervation of bronchial smooth muscle can lead to profound impairment of clearing of secretions and, in turn, lead to atelectasis of large lung segments.

As part of the screening for dysautonomia, patients should also be carefully examined for development of adynamic ileus. This occurs in about 1 in 10 patients with severe Guillain-Barré syndrome and is recognized by loss of abdominal sounds, expansion of the abdominal girth, and clearly demonstrable enlarged colonic loops on abdominal x-ray (Figure 23.1). Perforation of the colon is a very concerning complication which can substantially change the outcome of a recoverable neurologic illness, and can even lead to in-hospital death.

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FIGURE 23.1 Marked dilated colonic loops on abdominal X-ray (A) and confirmed on abdominal CT scan (B).

The treatment of patients with adynamic ileus is mostly parenteral nutrition for several weeks, rectal and oral suction tubes, and in more severe cases, a therapeutic decompressive colonoscopy. The use of erythromycin might be considered if patients have gastroparesis, but its side effects (cardiac arrhythmias) in patients with severe dysautonomia may make it a less favorable choice. We discourage the use of metoclopramide as promotility agent, because it has been associated with the occurrence of asystole in GBS.

In our patient, being on a mechanical ventilator made the use of multiple doses of intravenous morphine much safer, and blood pressure could be controlled within the set goal of systolic blood pressures of 100–140 mmHg. The nursing staff was particularly careful with tracheal suctions trying to avoid multiple passages and straining that could lead to bradycardia and hypotension. The blood pressure swings became less apparent in the following weeks with gradual disappearance over time.

Acute autonomic failure in GBS usually resolves before the patient starts to improve motor function. Marked orthostatic hypotension may persist during the recovery phase. Whether this is due to persistent autonomic failure or a result of long-standing bed rest is undetermined.

KEY POINTS TO REMEMBER REGARDING AUTONOMIC FAILURE IN GUILLAIN-BARR SYNDROME

· Acute autonomic failure is common in severe presentations of GBS. Marked blood pressure fluctuations or sustained hypertension are the most concerning manifestations.

· Hypertensive surges can be treated with morphine, clonidine, or if necessary, an infusion of a calcium channel blocker, such as nicardipine.

· Vagal spells may lead to prolonged episodes of asystole, and a transcutaneous pacemaker might be needed.

· Every bedridden patient with severe GBS is at risk of developing severe adynamic ileus, and treatment may require a period of parenteral nutrition or colonoscopic decompression.

Further Reading

Cortese I, Chaudry Y, Do YT. Evidence-based guideline update:Plasmapheresis in neurologic disorders:report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology 2011;76;294–300.

Hughes RA, Wijdicks EFM, Barohn R, Benson E, Cornblath DR, Hahn AF, Meythaler JM et al. Practice parameter: immunotherapy for Guillain-Barr syndrome: report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology 2003; 61:736–740.

Hughes RA, Wijdicks EFM, Benson E, Cornblath DR, Hahn AF, Meythaler JM, Sladky JT et al. Supportive care for patients with Guillain-Barr syndrome. Arch Neurol 2005; 1194–1198.

Mukerji S, Aloka F, Farooq MU, Kassab MY, Abela GS. Cardiovascular complications of the Guillain-Barr syndrome. Am J Cardiol 2009; 104:1452–1455.

McDaneld LM, Fields JD, Bourdette DN et al. Immunomodulatory therapies in neurologic critical care. Neurocrit Care 2010; 12:132–143.

Van Doorn PA, Ruts L, Jacobs BC. Clinical features, pathogenesis, and treatment of Guillain-Barr syndrome. Lancet Neurol 2008; 7:939–950.