Scrub typhus with bilateral sensorineural hearing loss: A unique case report

Juhi Dixit; Ranveer Singh Jadon; Animesh Ray; Piyush Ranjan; NK Vikram; Rita Sood

doi:10.4103/0972-9062.308809

CASE REPORT

Year : 2020 | Volume : 57 | Issue : 1 | Page : 101-103

Scrub typhus with bilateral sensorineural hearing loss: A unique case report

Juhi Dixit, Ranveer Singh Jadon, Animesh Ray, Piyush Ranjan, NK Vikram, Rita Sood
Department of Medicine, All India Institute of Medical Sciences, New Delhi, India

Date of Submission	16-May-2018
Date of Acceptance	05-Apr-2019
Date of Web Publication	05-Feb-2021

Correspondence Address:
Dr Ranveer Singh Jadon
Room No. 3070, 3rd Floor, Teaching Block, All India Institute of Medical Sciences, New Delhi–110 029
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/0972-9062.308809

Abstract

Keywords: Pure tone audiometry; Orientia tsutsugamushi; scrub typhus; sensorineural hearing loss

How to cite this article:
Dixit J, Jadon RS, Ray A, Ranjan P, Vikram N K, Sood R. Scrub typhus with bilateral sensorineural hearing loss: A unique case report. J Vector Borne Dis 2020;57:101-3

How to cite this URL:
Dixit J, Jadon RS, Ray A, Ranjan P, Vikram N K, Sood R. Scrub typhus with bilateral sensorineural hearing loss: A unique case report. J Vector Borne Dis [serial online] 2020 [cited 2021 Apr 18];57:101-3. Available from: https://www.jvbd.org/text.asp?2020/57/1/101/308809

Scrub typhus is a mite-borne infection caused by Orientia tsutsugamushi which is an obligate intracellular gram-negative coccobacilli^[1]. It is transmitted by the bite of larval mites (also known as chiggers) of Leptotrombidium deliense which acts as a vector as well as reservoir^[2]. Humans are accidental hosts. This can manifest as a mild self-limiting febrile illness to severe life-threatening illness complicated by acute respiratory distress syndrome (ARDS), acute renal failure, acute liver failure, myocarditis, encephalitis, etc. Data compiled in a study from northwest India shows the occurrence of pathognomonic eschar from 4–46% at Vellore and Puducherry, respectively^[3]. There has been a recent resurgence of the disease in various parts of southeast Asia including India and its protean manifestations make the diagnosis sometimes difficult. Therefore, any acute febrile illness with multisystem involvement in an endemic area calls for suspicion of rickettsial disease.

We hereby report a patient who presented with undifferentiated febrile illness and subsequently she developed sensorineural hearing loss (SNHL) during the hospital stay. She was finally diagnosed as having scrub typhus and her illness and SNHL recovered with doxycycline treatment.

Case

A 38-yr-old lady, known case of chronic kidney disease stage-III, presented at OPD, All India Institute of Medical Sciences, New Delhi with complaints of moderate grade, continuous fever for the past 15 days associated with chills. She also complained of headache which was holocranial and boring type for 15 days. She had no history of any rash, arthralgia, myalgia, eschar, bleeding from any site, and visual disturbance. There was also no history of cardiovascular, respiratory, gastrointestinal, or genitourinary complaints. On examination, she had pallor, tachycardia (120/min) with normal blood pressure (110/70 mm Hg) and respiratory rate (22/min). There was no lymphadenopathy, eschar, neck rigidity, and elevated jugular venous pressure. Systemic examination revealed no abnormality. The patient was admitted and evaluated. Her initial investigations revealed Hb–8.4 gm/dl, TLC–7400/mm³ (N = 72, L = 20, M = 6%, and E = 2%, platelets–108,000/mm³. Her ESR was 48 mm at the end of the first hour. Peripheral smear for malarial parasite and dengue serology were negative and urine routine examination was normal. Her chest radiograph and abdominal ultrasound did not reveal any abnormality. She was empirically started on ceftriaxone considering the possibility of enteric fever. Subsequently, her widal test came to be negative. Considering as a case of undifferentiated fever, serology for scrub typhus and leptospira were sent.

On Day 5 of admission, she complained of sudden onset bilateral decrease in hearing, which was non-progressive. It was associated with giddiness. There was no complaint of ear fullness, earache, ear discharge, tinnitus, and fluctuation in symptoms. She was not receiving any ototoxic drug (aminoglycoside or loop diuretic). In view of impaired hearing, ENT consultation was sought but her otoscopic examination was normal. Her pure tone audiometry (PTA) test was performed which revealed bilateral moderate to severe SNHL. The auditory threshold was reduced to 80 dB in the right ear and 75 dB in the left ear [Figure 1]. Meanwhile, her serology for scrub typhus came out positive and she was started oral doxycycline at a dose of 100 mg twice a day. She responded within 48 h of initiating the doxycycline. Her fever subsided and hearing loss recovered partially which was confirmed by repeat PTA performed seven days later showing an auditory threshold of 55 dB bilaterally [Figure 2]. Subsequently, she was discharged and followed up after one month with PTA which showed further improvement [Figure 3].

Figure 1: Pure tone audiometry (Day 1) showing bilateral severe Sensorineural hearing loss (SNHL).

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Figure 2: Pure tone audiometry (Day 7) showing bilateral moderate SNHL.

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Figure 3: Pure tone audiometry after one month showing only mild bilateral hearing loss.

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Nervous system manifestations of scrub typhus range from aseptic meningitis to frank meningoencephalitis^[4]. Hearing impairment in scrub typhus is a rarely encountered entity in clinical practice^[2]. Furthermore, sudden bilateral SNHL is an extremely rare presentation. Auditory disturbances in the form of otalgia and tinnitus have been reported. These manifestations usually appear during the second week of illness^[5].

Sensorineural hearing loss has been rarely reported in patients with Rickettsia rickettsia, R. typhi, R. coronii^[6]. In a study conducted by Premaratna et al^[5] in Sri Lanka, six out of 32 patients of scrub typhus had reported auditory symptoms out of which three had deafness (type of deafness was not characterized).

Two mechanisms have been proposed for the involvement of vestibulocochlear nerve in scrub typhus; the first being direct central nervous system invasion and vasculitis with subsequent damage to cochlear nerve^[7],[8]. The second mechanism involves vasculitis of vasa vasorum of the cochlear nerve by secondary immune mechanism^[3]. Interestingly, a unique histologic study conducted in sections of the temporal bones from five British soldiers who died in 1944 due to rickettsial infections (epidemic typhus) during the last war in Eastern Asia revealed multiple ‘typhus nodules’ and extensive interstitial neuritis of the VIII nerve and demyelination of the nerve fibres. There were also widely scattered aggregations of mononuclear cells in the inner ear. This unique study was based on the Hallpike collection of temporal bone sections^[9].

Management involves treatment with doxycycline. Hearing impairment improves gradually and complete recovery usually occurs after one month. [Table 1] shows a compilation of various case reports of scrub typhus with SNHL. Most of the patients who suffered from hearing loss were young females. The mean age was 38.2 ± 16.6 yr and 80% were females. Three out of five patients (60%) had pathognomonic eschar. The average duration of onset of symptom at the time of presentation was 9 ± 1.4 days with a recovery time of 29 ± 4.12 days.

Table 1: Compilation of case reports of sensorineural hearing loss in scrub typhus^{[10],[11],[12],[13]}

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Comparing with these observations, the present patient was also a 38-yr-old female who developed hearing loss on Day 20 of the febrile illness. She did not have any eschar. Her symptoms showed improvement after one week of doxycycline therapy and further recovery was documented in PTA performed after one month which showed significant recovery although mild SNHL in the left ear and moderate in the right ear was persisting [Figure 3].

With the resurgence of scrub typhus in recent times, it should be considered as one differential diagnosis in any patient who presents with acute febrile illness and otic symptoms like hearing loss without any otoscopic abnormality.

Conflict of interest: None

References

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