Figure 3: Repeat Pure Tone Audiometry at 12 weeks postpartum
Discussion
This is a case of scrub
typhus in pregnancy with respiratory and possible meningoencephalitis
complications. The diagnosis of scrub typhus in our case was delayed due
to predominant respiratory symptoms, absence of eschar and the initial
false negative serology result with SD Bioline Tsutsugamushi RDT
(Standard Diagnostics Inc, Korea). 8 The appearance of
audiological symptoms such as hearing loss in acute undifferentiated
febrile illness should raise suspicion for scrub typhus infection.2 Audiological symptoms were present in almost 30% of
the cases. 2 A hospital based review of records of 33
pregnant women with scrub typhus infection reported 4.5% incidence
although none of the cases reported hearing loss. 9Similar to non pregnant patients, the severity of disease is associated
with delayed diagnosis and treatment leading to multiorgan failure. It
is associated with poor obstetric outcome such as maternal admission to
intensive care unit, miscarriage, fetal demise and preterm birth
especially in 3rd trimester in atleast 50% of the
cases. 9,10 Consistent with other studies, maternal,
fetal and neonatal outcomes were favorable in our case as there was no
multi organ dysfunction. There are also few case reports on vertical
transmission. 11 However the baby’s serology in our
case came negative for scrub typhus infection. Case series reported by
Premaratna et al have shown objective improvement in hearing loss in
those who recovered without any complications. 2 All
cases except one responded to course of tetracycline/chloramphenicol.
One patient died due to myocarditis and meningoencephalitis due to
delayed diagnosis. As a result of delayed diagnosis, our case developed
clinical features suggestive of meningoencephalitis. The permanent loss
of hearing might have been a sequela to this complication. A hypothetic
explaination on rarity of literature on permanent hearing loss due to
scrub typhus in pregnancy may be due to shift in Th 1 to Th 2 immune
modulation.12 Possibly, neuroinflammation may be less
pronounced due to the Th1 to Th2 shift in early stage of infection
followed by overwhelming infection at later stage leading to more
generalized meningoencephalitis. A reasonable postpartum time period of
3 months was allowed to recover from pregnancy associated hearing loss
as seen in some healthy women. 13 Telephonic follow up
with spouse at 6 months revealed no subjective improvement in hearing.
This case report is probably the first of its kind in describing the
permanent hearing loss following scrub typhus in pregnancy. Although no
cause effect relationship can be deduced from this report, we still
generate a hypothesis based on hormonal mediated immunomodulation and
permanent hearing loss in scrub typhus infection.
Conclusion
As clinicians, we need to be vigilant about these rare and atypical
presentations given the endemic nature of scrub typhus in southern belt
of the country. Timely diagnosis and appropriate treatment is the key
aspect to prevent further complications. Possibly, hearing loss in
pregnancy due to scrub typhus could be permanent due to synergistic
effect of hormone induced changes in immunomodulation and
meningoencephalitis.
Acknowledgement: We would like to thank Mr. Sangay Tshering, Audiologist
at the JDWNRH, Thimphu for the providing the results of Pure Tone
Audiometry in digital form.
Conflict of interest: There is no conflict of interest in publication of
this article.
Funding: None.
Ethical approval: Ethical approval is not needed for case report in
de-identified patients.
List of abbreviations
PTA: Pure Tone Audiometry
ABR: Auditory Brainstem Response
Authors contribution
ST was involved in conception and design, acquisition of data, analysis
and interpretation of data, revising it critically for important
intellectual content, final approval of the version to be published and
agreed to be accountable for all aspects of the work.
ND was involved in conception and design, acquisition of data, revising
it critically for important intellectual content, final approval of the
version to be published and agreed to be accountable for all aspects of
the work.
DD was involved in conception and design, acquisition of data,
interpretation of data, revising it critically for important
intellectual content, final approval of the version to be published and
agreed to be accountable for all aspects of the work.
TO was involved in conception and design, acquisition of data,
interpretation of data, revising it critically for important
intellectual content, final approval of the version to be published and
agreed to be accountable for all aspects of the work.
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