Guillain-Barré syndrome, recently associated with Zika virus infection, is a progressive paralysis of acute onset, but fortunately, it recovers over time in most cases.
The Guillain-Barré syndrome (GBS) is an autoimmune neurological disorder based on which the immune system attacks a person to myelin. Myelin is a substance with a high lipid content that sheaths the nerves. It is as if it were the insulation of electrical cables.
If the myelin sheath is damaged, the nerves cannot work properly, and the orders sent by the brain to the muscles do not reach them, causing paralysis and alteration of the tendon reflexes. In addition, although it does not always occur, sensitivity can also be altered for the same reason.
This entity was first described in the 19th century by several different doctors. Still, it was not until World War I that two French doctors (Georges Guillain, Jean-Alexandre Barré and André Strohl) published an article describing two cases of soldiers affected by this condition by conducting electrophysiological studies and, in addition, detecting a characteristic feature, which is the elevation of proteins in the cerebrospinal fluid. For this reason, it is called Guillain-Barré Syndrome (although the name of Strohl and Landry, who was the first to describe it in 1859, are unfairly omitted).
In reality, GBS is not a single disease but rather a spectrum of different types of clinical presentation of the underlying autoimmune disorder as its cause. Thus, there are different forms of clinical presentation:
- Acute inflammatory demyelinating polyneuropathy: this is the most common form, the classic Guillain-Barré Syndrome.
- Acute motor axonal neuropathy: more common in children and young adults.
- Acute sensory-motor axonal neuropathy: it is a rarer form in which sensory involvement predominates. There is also a rare form of pure sensory involvement.
- Miller-Fisher syndrome: accounts for 5% of cases. The eye muscles are affected, reflexes disappear, and there is ataxia (incoordination of movements).
Guillain-Barré Syndrome in any of its forms is rare. It appears in 1-4 of every 100,000 people a year. Although it can occur at any age, it is more common between 30 and 50 years, somewhat more common in men than in women. Its presentation is acute and progressive over hours or a few days.
At two or three weeks is when the symptoms are at their worst, and later a slowly progressive recovery occurs, although there are patients who remain sequelae. It has a mortality of less than 5% with adequate and early treatment. 85% of patients are objectively recovered after one year, although a feeling of chronic fatigue may remain.
In recent weeks, dozens of those affected have been detected in Peru. For months, the name of this syndrome has appeared related to the Zika virus outbreak that is hitting Latin America and is spreading to dozens of countries.
Guillain-Barré syndrome and Zika virus infection
Recently, the alarm has grown over the association of Zika virus infection and Guillain-Barré syndrome, and other neurological disorders.
During the Zika outbreak in French Polynesia between November 2013 and February 2014, 74 cases of neurological or autoimmune disease were reported, of which 42 were GBS cases. Of these 42 cases, 37 had presented symptoms and laboratory tests suggestive of Zika virus infection. In that outbreak, there were almost 9,000 affected. Meningitis, meningoencephalitis, and myelitis have also been described.
In the current outbreak in the Americas, concern has grown about the association of Zika with Guillain-Barré syndrome. In several of the affected countries, GBS cases have been described with a higher incidence than expected, coinciding with the Zika epidemic in them. Of the investigated cases, there are some in which previous Zika virus infection has been confirmed.
For example, in Brazil, 1708 cases of GBS were reported in 2015, representing an increase of 19% compared to 1,439 cases in 2016. Also in other countries such as Venezuela, Colombia, El Salvador, and Suriname have reported an unexpected increase in cases of GBS between December 2015 and February 2016. In some cases, Zika virus infection has been confirmed. This is not to say that all current cases of Guillain-Barré syndrome in these countries are due to the Zika virus, although it could explain this excess of cases.
Research is underway in all of these countries to clarify the relationship between the Zika virus and Guillain-Barré syndrome. Although the findings so far are consistent with an association between the circulation of the Zika virus and the appearance of a greater number of GBS cases, the exact mechanism by which this would occur, and the associated risk factors have not yet been clarified.
The World Health Organization believes that between March and April 2016, it will establish more accurately the relationship between GBS and the Zika virus. In any case, both the diagnosis and the treatment of Guillain-Barré syndrome would be usual for these patients.