For Eloïse, it started with swelling behind her right ear. At first, she thought it was tension. But after a few days, she noticed while brushing her teeth in the morning that water was dripping from the corner of her mouth when she rinsed it out. «I looked in the mirror and saw that when I smiled, the right corner of my mouth stayed down,» says the 12-year-old.
On the same side of her face, she could no longer close her eye completely or frown. She showed her father the symptoms, but then went to the riding camp as usual, where she was helping out during the holidays.
«I didn't feel ill, so I wasn't worried,» says Eloïse. Her mother Virginia felt differently. She was terrified when she heard about her daughter's symptoms: «I had never heard of children suddenly having half their face paralysed.»
Facial nerve paralysis in Switzerland
Facial paralysis, as it is known in medical jargon, is actually rare, but children's hospitals are familiar with the condition. The University Children's Hospital Zurich records an average of one case per week, with more cases in summer and autumn and fewer during the rest of the year.
At the paediatric clinic of Inselspital Bern, there are even two to three cases per week during the summer months, totalling 20 to 30 per year. Exact figures are not available. Estimates range from 5 to 7 cases per 100,000 children. The figure for adults is slightly higher, at 20 to 30 per 100,000. Facial nerve paralysis is the most common form of spontaneous paralysis in children.
Two different shapes
On that summer morning, Eloïse's father called a medical hotline and was instructed to take the child to A&E immediately. He picked up his daughter from riding camp and drove her to the emergency room at Zurich Children's Hospital.
«That's the right approach,» says Patrick Meyer Sauteur, infectious disease specialist at the University Children's Hospital Zurich. «Facial paralysis should be assessed in hospital as quickly as possible.» Although almost all children recover completely, it is a serious condition.
If the facial nerve swells up during an infection, it can hardly spread. This limits its function.
Patrick Meyer Sauteur, infectious disease specialist
At the hospital, Eloïse had to undergo various tests. «Facial paralysis is understandably very worrying for parents. It is also a situation that we doctors have to take very seriously,» says Meyer Sauteur.
At the outset, it is particularly important for medical professionals to distinguish between central and peripheral facial paralysis. «Central facial paralysis means one thing to us: danger!» With this form of facial paralysis, the problem lies in the brain, caused, for example, by a tumour or stroke – which is rare in children. If it is a stroke, quick action must be taken to protect the affected brain tissue.
Peripheral facial paralysis is much more common
Far more common is the much more harmless variant, peripheral facial paralysis. Here, the problem lies not in the brain, but in the facial nerve – the facial nerve.
Senior physician Meyer Sauteur explains: «The facial nerve runs through a narrow bony canal at the base of the skull. If inflammation occurs as a result of an infection, the nerve swells but cannot expand in the bony canal. The resulting tension can impair its function.» The cause of the paralysis is therefore not direct damage to the nerve tissue, but usually an infection.
In rare cases of central facial paralysis, it is typically still possible to frown on the paralysed side.
Doctors can quickly distinguish between central and peripheral facial paralysis. The most important difference is that children affected by central facial paralysis can typically still frown on the side affected by the paralysis.
Ticks transmit bacteria
The swelling behind Eloïse's ear was not, as she had assumed, tension, but a swollen lymph node caused by an infection. This probably led to inflammation and, a few days later, paralysis; Eloïse was therefore suffering from peripheral facial paralysis. First, images of her head were taken using magnetic resonance imaging. Then the specialists tried to find out which bacterium or virus had caused the inflammation.
The bacterium Borrelia burgdorferi is responsible for around 30 to 40 per cent of peripheral facial nerve palsy cases. This is referred to as neuroborreliosis, a form of Lyme disease that affects the nervous system. Borrelia bacteria are transmitted by tick bites. This explains the seasonal increase in cases in paediatric clinics.
A lumbar puncture is the only way to reliably diagnose neuroborreliosis.
Sandrine Cornaz Buros, neuropaediatrician
In summer and autumn, ticks wait on low-growing plants for a host to attach themselves to. The fact that schoolchildren and teenagers are particularly affected by facial paralysis is also related to the transmission of Borrelia bacteria: babies and toddlers spend less time in the woods and are therefore less at risk of being bitten by ticks.
In Switzerland, between 5 and 50 per cent of ticks are infected with these bacteria, depending on the region, although only around one per cent of all people who are bitten by a tick develop Lyme disease. The risk increases the longer the tick remains attached to the body.
The worst part of the examination
A lumbar puncture is performed to determine whether neuroborreliosis is present. «We need the cerebrospinal fluid to correctly diagnose neuroborreliosis and to rule out other, rarer causes,» says infectious disease specialist Meyer Sauteur.
Sandrine Cornaz Buros, senior physician at the paediatric clinic of Inselspital Bern, also emphasises: «A lumbar puncture is the only way to reliably diagnose neuroborreliosis.» If only the blood is tested, the results can sometimes be inaccurate – especially false positives.
Although the examination is not dangerous, it can be painful. For Eloïse, too, the spinal tap was the worst part of her marathon of tests. Patrick Meyer Sauteur is currently leading a research project at the University Children's Hospital in Zurich that aims to improve the diagnosis of Lyme disease.
Antibiotics or cortisone
After a lumbar puncture, you have to wait a few days for the definitive result. «It is not uncommon for the paralysis to have already disappeared by the time we inform the parents of the results,» says Meyer Sauteur. If Lyme disease is diagnosed, the child must undergo antibiotic treatment, even if the symptoms have already subsided. This is to prevent possible later consequences. If no Borrelia bacteria are found, the child is given a cortisone preparation.
Could antibiotics and cortisone be given to children as a preventive measure to spare them from numerous examinations? «Both are drugs with effects and side effects,» replies neuropaediatrician Cornaz Buros. «We want to choose the right treatment and not over-treat the child.»
In most children, the paralysis would disappear without any treatment.
Patrick Meyer Sauteur, infectious disease specialist
While antibiotics combat bacteria, cortisone is an anti-inflammatory that reduces swelling in the nerve. To make matters worse, antibiotics for neuroborreliosis in children under eight years of age previously had to be administered intravenously.
For the infusion, the children were forced to go to the hospital every day for two weeks. At the beginning of the year, the Children's Hospital Zurich changed its practice: «There are new studies that show that the antibiotic doxycycline can also be given to younger children in tablet form,» explains Meyer Sauteur.
The pathogen often remains unknown
Sandrine Cornaz Buros emphasises that neuroborreliosis is only responsible for some cases of facial paralysis: «There are many other pathogens that can cause facial paralysis.» Very often, it is not possible to determine which pathogen is responsible for the inflammation. If the cause is unknown, it is referred to as idiopathic facial paralysis or Bell's palsy – the most common form.
In Eloïse's case, too, the cause could not be found. After a long day in the emergency room, she was allowed to go home. She was given cortisone tablets to take for seven days, eye drops and an ointment to protect her right eye from drying out. The twelve-year-old and her parents were warned that the paralysis could worsen in the following days, which indeed happened.
Causes of facial nerve paralysis in children
- Bell's palsy: No cause can be found for idiopathic facial paralysis. Affects 50 to 70 per cent of cases.
- Neuroborreliosis: This is caused by the bacterium Borrelia burgdorferi (Borrelia). Affects 30 to 40 per cent of cases.
- Viral infection: influenza, chickenpox (varicella or shingles), mumps, herpes simplex virus, middle ear infection or others. Affects 10 to 20 per cent of cases.
- Stroke: very rare
- Tumour in the facial nerve area: very rare
- Accident: Direct damage to the facial nerve, very rare.
The maximum severity is usually reached after about a week. After two and a half weeks, Eloïse was able to move the affected side of her face a little again, and after about four weeks, the symptoms had disappeared. According to Patrick Meyer Sauteur, this is a typical course of events. After three months at the latest, virtually all affected children can move their faces normally again. The prognosis for adults is not quite as good, with between 70 and 85 per cent of those affected making a full recovery.
«In most children, the paralysis would even disappear without any treatment,» explains infectious disease specialist Meyer Sauteur. However, neuroborreliosis should not be overlooked. The earlier the diagnosis is made and other causes ruled out, the better. Therefore, unilateral facial paralysis is an emergency that requires immediate hospital treatment.
