Microbe that causes strangles behind a serious brain infection in a man – case report

The bacterium that causes strangles in horses was behind a dangerous brain infection in a man in Belgium, doctors report.
Image by Rainer Maiores

The bacterium that causes strangles in horses was behind a dangerous brain infection in a man in Belgium, doctors report.

The man was diagnosed with meningoencephalitis – a serious neurological condition resembling both meningitis and encephalitis, with inflammation of both the brain tissue and its covering membrane.

The bacterium behind the infection was identified as Streptococcus equi subspecies equi.

The 69-year-old Caucasian was admitted to the emergency department of Antwerp University Hospital after returning from a one-month vacation to Myanmar that included horseback riding.

The patient’s medical history included gout, food poisoning, and neurosurgical reconstruction of the skull after a fracture suffered five years earlier as a result of a fall from a horse.

For the preceding few days, the patient had been increasingly tired and drowsy, with complaints of a headache, left-sided ear pain, and night sweats. The day before admission the patient had become increasingly confused.

On the day of admission, he was found by his wife lying on the floor of his home, confused, agitated, shivering, and lacking bladder control.

On admission, his temperature was elevated and his heart rate was 111 beats per minute, Jeroen Kerstens and his colleagues reported in the journal, Case Reports in Neurological Medicine. Diagnostic work included blood tests, a chest x-ray and a CT scan of the brain.

Bacterial meningitis was suspected, and after obtaining two sets of blood cultures, intravenous antibiotics were given.

Shortly after starting the antibiotic therapy, the patient became more drowsy and developed left-sided paralysis, left-sided central facial palsy, and right-sided head and eye deviation.

The patient was admitted to the intensive care unit and was intubated and ventilated the next day because of increasing difficulties with breathing.

Cerebrospinal fluid cultures were positive for Streptococcus equi.

Intravenous antibiotics were continued for 21 days.

Four days after treatment began, the patient was weaned from the ventilator and extubated. Initially, the patient remained very agitated and disoriented.

Nine days after admission to intensive care, the patient was transferred to the neurology department. Later, the Streptococcus equi was identified as S. equi subspecies equi by an outside agency.

The patient initially recovered completely. He had no complaints apart from mild gait disturbances and light-headedness at a follow-up appointment three months after discharge.

One month later, the patient was readmitted with intracranial bleeding, and CT scans showed multiple areas of bleeding on the right side of the brain. More imaging confirmed the presence of a suspected superficial dural arteriovenous fistula, which was dealt with by a neurosurgeon. He was subsequently discharged home.

Discussing the circumstances of the case, the doctors said they had been able to find only three other cases in the scientific literature in which S. equi subspecies equi had infected the central nervous system in humans. “In these cases, direct contact with horses could be pinpointed.”

The first case, published in 2003, involved a 13-year-old Canadian boy who lived on a horse farm. He presented with a two-day history of fever, increasing neck stiffness, headache, poor appetite, nausea, vomiting, lethargy, light sensitivity, deafness, and poor coordination.

He was diagnosed with bacterial meningitis and went on to develop hydrocephalus. He recovered with only mild problems with coordination, but his hearing did not recover and he received a cochlear implant.

The second case involved a 75-year-old woman admitted with fever and stupor who was successfully treated with 10 days of intravenous antibiotics. She later stated that her neighbours were horse owners and she had visited their farm within two weeks of admission.

Very recently, a 13-year-old-boy with systemic lupus presented with sepsis and meningitis after contact with a sick pony. Although he recovered fully after eight weeks of antibiotics, the case was complicated by subdural pus requiring neurosurgical evacuation.

“In our patient, recent contact with infected horses in Myanmar was presumably the cause of the disease, and prior surgery was a possible route of entry,” they said.

“In summary,” they continued, “we report a rare case of S. equi subsp. equi meningoencephalitis that initially recovered well after treatment with antibiotics and glucocorticoids.”

The cerebral lesions seen on an MRI not only caused meningitis but also meningoencephalitis, and the postinfectious dural fistula accompanied by brain bleeding illustrated the aggressive nature of the toxins released by this bacterium, with a further inflammatory reaction.

The full case report team comprised Kerstens, Busra Durmus, Stijn Lambrecht, Ingrid Baar, Margareta Leven, Thijs Van Der Zijden, Paul Parizel, Tomas Menovsky, Martin Lammens, and Philippe Jorens.

Meningoencephalitis with Streptococcus equi Subspecies equi Leading to a Dural Arteriovenous Fistula
Jeroen Kerstens, Busra Durmus, Stijn Lambrecht, Ingrid Baar, Margareta M. Ieven, Thijs Van Der Zijden, Paul M. Parizel, Tomas Menovsky, Martin M. Y. Lammens, and Philippe G. Jorens.
Case Reports in Neurological Medicine, Volume 2021 |Article ID 9898364 https://doi.org/10.1155/2021/9898364

The study, published under a Creative Commons License, can be read here.


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