Hearing Loss from S. Suis Meningitis In A Middle-Aged Couple

Abstract

Streptococcus suis is a bacterial pathogen causing a wide range of infections including meningitis, lung infections, arthritis, sepsis and endocarditis.¹ Over the years, an increasing number of cases have been reported among humans especially in countries in Southeast Asia specifically in Vietnam and Thailand where pig-rearing is common.² One of the prominent symptoms of S. suis infection is hearing loss that may be present during the onset or a few days after.¹ We report two cases of adult S. suis meningitis presenting with bilateral hearing loss.

CASE REPORT

Our first patient was a 57-year-old man who presented with a one day history of generalized weakness initially unaccompanied by any other symptoms. The previous day, he was still able to walk but was generally weak, and preferred to stay in bed. That evening, he developed high grade fever (40oC) that was temporarily relieved by paracetamol. There were two episodes of vomiting previously ingested food but no headache. By late evening, he was noted to have increased sleeping time, opening eyes spontaneously, responding mostly with yes or no, and following commands but drowsing back to sleep. On the day of admission, he could sustain spontaneous eye opening with no regard and groaned in response to questions without following commands. High grade fever persisted and he was rushed to the Emergency Room. On examination, he was febrile at 40.5oC, hypertensive at 160/80mmHg, tachycardic at 109 with a Glasgow Coma Scale (GCS) of 9/15 (E4V1M6), and was given O2 support at 1LPM by nasal cannula. He presented with spontaneous eye opening, no regard and did not follow commands. He had meningeal signs- nuchal rigidity but no Kernig’s sign. Cranial CT scans showed no acute territorial infarct or intracranial hemorrhage, and a stable chronic lacunar infarct versus prominent perivascular space in the left lentiform nucleus. A COVID rt-PCR test was negative. Complete blood count showed leukocyte count of 5,220/mm3 with 72% neutrophils and a platelet count of 57,800/mm3. Bleeding parameters showed prothrombin time of 14.4 seconds, INR of 1.23 and an elevated PTT of 45.3. He was started on Meropenem and Vancomycin and admitted to the Neurological Critical Care Unit while awaiting clearance for lumbar puncture (being on anti-coagulants).

Our second patient was his wife, a 51-year-old professional singer with no known co-morbidities who was also admitted due to fever and headache. At the time her husband was admitted, she had febrile episodes as high as 40oC associated with pressure-like headache over both occipital

areas (rated PS 7/10) as well as joint pain and nape pain. There were no associated cough, colds, dysuria, otalgia or otorrhea. Paracetamol afforded temporary relief but fever intermittently recurred the next day and she was admitted for further evaluation and management even though her COVID rt-PCR test was negative. On initial examination at the ER, she was still febrile at 38.5C. She was awake, coherent and oriented to 3 spheres. Complete blood count showed leukocytosis, while C Reactive Protein and Erythrocyte Sedimentation Rate were elevated. Magnetic Resonance Imaging (MRI) showed diffuse FLAIR hyperintensities along bilateral cerebral sulci and cerebellar interfoliar spaces with associated leptomeningeal enhancement. There was also enhancement along the ventral surface of the brain stem. A CNS infection was suspected and lumbar puncture was performed. Her CSF showed gram positive cocci in pairs and chains with a possible streptococcus infection, but no fungal elements or acid fast bacilli. Both CSF and blood culture and sensitivity specimens tested positive for Streptococcus suis sensitive to Penicillin. She and her husband were started on intravenous Penicillin.

Both patients had improvement in headache and nape pain over the next two days. However, they both reported persistent, progressive dizziness and bilateral hearing loss, and showed signs of vestibular dysfunction. The vestibular dysfunction was so severe that both patients were bed-bound and needed assistance in ambulating throughout their hospital stay. Their hearing was described as distorted, with a sensation of being underwater. Hearing tests revealed profound sensorineural hearing loss on the right and moderate sensorineural hearing loss on the left for the husband, and severe sensorineural hearing loss on the right and moderate sensorineural hearing loss on the left, downsloping at 6000 to 8000 Hz in both ears for the wife. Both patients were started on intravenous Dexamethasone, which they completed (together with Penicillin) over the course of 16 days. They were also given Betahistine tablets for dizziness, metoclopramide for nausea and Vitamin B complex. Repeat cranial MRI showed significant interval regression in the diffuse FLAIR hyperintensities and associated leptomeningeal enhancement along bilateral cerebral sulci and cerebellar interfoliar spaces. Repeat lumbar punctures showed no growth of any pathogen and resolution of S. suis infection. Serial hearing tests showed stable hearing loss for both patients.

After 2 months from the onset of infection, both patients continued to experience dizziness, vestibular dysfunction and hearing loss. Although both were now able to ambulate, they still needed assistance in daily activities including driving. They still could not tolerate sudden head movements; even nodding and turning the head from side-to- side elicited dizziness. The wife’s singing was greatly affected as the right ear had persistent severe hearing loss. Sounds were perceived

as distorted, described as ‘scratches;’ her right ear would hear higher frequencies, while the left ear heard lower frequencies. The perceived imbalance in frequencies posed a challenge to singing the right tune, but she continues to perform and sing professionally despite her hearing condition. She adapted through repetition, practicing until she achieved muscle memory in getting the right tone. They were offered several options for managing the residual symptoms including rehabilitation, hearing aids and early cochlear implantation.

It was subsequently determined that they both ate at a Korean barbecue restaurant days before the onset of symptoms. However, they ordered chicken barbeque and did not eat any pork dishes.