Scrub typhus is a zoonosis, widely prevalent in many
parts of Asia including India(1). Though there are reports of this
infection occurring not uncommonly in South India(2,3), in clinical
settings, the index of suspicion is still low. The typical rash and
eschar may not be always present(3), leading to missed diagnosis. Scrub
typhus is associated with about 10% mortality in our area in adults(3).
There are no reports, to the best of our knowledge, on manifestations of
scrub typhus in children in India. We report scrub typhus in 2 girls
aged 10 and 12 years, respectively.
Two girls, both from areas around Vellore were
admitted in November 2003 with prolonged fever. Their specific features
are presented below.
Case 1: This 10-year-old girl presented with
history of fever and myalgia for 10 days and headache and vomiting for 3
days. On examination, she looked toxic and had a temperature of 102.4ºF.
Other vital signs were stable and sensorium was normal. There were skin
rashes, no conjunctival suffusion, petechiae, eschar or significant
lymphadenopathy. Systemic examination was normal except for a palpable
liver of 2 cm. Investigations revealed hemoglobin of 10.8 g/dL, total
leukocyte count of 4400/mm3, with normal differential count, platelet
count of 73,000/mm3 and normal prothrombin time and activated partial
thromboplastin time. Smear for malarial parasite and serology for Widal
test were negative and ALT was 65 U/L. Blood culture was sterile. Chest
X-ray and urine routine were normal. Mantoux test was negative.
She was empirically started on intravenous cefotaxime. She continued to
have fever and developed neck stiffness on day 4. CSF analysis done at
this time was normal. Fever persisted and signs of respiratory tract
infection were noticed on day 5. A repeat chest X-ray showed
uniform haziness in the left lower zone. Considering the possibility of
Mycoplasma pneumonia she was started on roxithromycin. However, fever
persisted and cold agglutinin was negative. At this point other causes
of prolonged fever were considered. Weil Felix test showed a titer of 40
for OXK antigen. Specific elisa for Orientia tsutsugamushi was positive.
A diagnosis of scrub typhus was made. Although the intensity of fever
was coming down with roxithromycin, it was still persisting. The child
was started on doxycycline and she became afebrile in 72 hours.
Doxycycline was given for a total of 7 days.
Case 2: This 12-year-old girl presented with
history of fever and cough for 15 days, loose stools for 5 days and one
episode of generalised tonic clonic seizures followed by altered
sensorium on the day of admission. On examination, she was febrile with
a temperature of 102ºF and was comatose with a Glasgow coma score of
7/15. She had a fine maculopapular rash over the face. There was no
conjunctival suffusion, eschar or significant lymphadenopathy. Her pulse
rate, respiratory rate and blood pressure were normal. She had signs of
meningeal irritation. The deep tendon reflexes were brisk and plantar
responses were extensor bilaterally. Fundus was normal. Other systems
were normal except for a palpable liver of 4 cm. Blood investigations
revealed hemoglobin of 12 g/dL, total leukocyte count of 25,900/mm3,
normal differential count, platelet count of 48,000/mm3, ALT of 81 U/L
and activated partial thromboplastin time of 68 seconds. Widal test and
smear for malarial parasite were negative. Chest radiograph was normal
and Mantoux test was negative. CT scan of brain was normal. CSF analysis
showed a total WBC count of 75 cells/mm3 with 95% lymphocytes, protein
152 mg/dL and sugar of 48 mg/dL; culture was sterile. She was started on
intravenous cefotaxime, phenytoin and mannitol. Weil Felix test showed a
titer of 80 for OXK antigen. Specific elisa for scrub typhus was
positive. She was started on intravenous chloramphenicol after which
there was a prompt defervescence with rapid normalisation of sensorium.
She was discharged after one week and on follow up was doing well.
Scrub typhus is prevalent in many parts of India(1).
It is caused by Orientia tsutsugamushi (earlier known as
Rickettsia tsutsugamushi) transmitted by the bite of larval
trombiculid mite. There are reports of outbreaks of scrub typhus in
southern India during the cooler months of the year(3). Both our cases
occurred during winter.
The clinical features can be quite non-specific
especially in an endemic area. The common symptoms described include
fever, severe headache, myalgia, dry cough and gastrointestinal
disturbances(3). However, combination of systems involved can vary. The
characteristic rash and eschar may not be always present. Common signs
described from children in Thailand include eschar at the site of bite,
maculopapular rash, lymphadenopathy and hepatosplenomegaly(4). There is
not enough data on children in India. Although eschar was absent in both
children, second child had a transient rash.
Non-specific lung infiltrates with predilic-tion to
the lower zone is described in scrub typhus(5). However this feature in
our first case, misdirected us towards a diagnosis of primary atypical
pneumonia. Complications described include interstitial pneumonitis,
atypical pneumonia, hepatitis, myocarditis, meningoencephalitis,
disseminated intravascular coagulation and multiorgan failure. In our
second child, features were suggestive of a meningoencephalitic process.
The wide clinical spectrum of this infection is
reflected by these two cases. The first child with prolonged fever was
relatively well whereas the second child with slightly more prolonged
course of the illness, required intensive care.
Diagnosis of scrub typhus is mainly by serological
methods(6). Weil Felix test has a low sensitivity and specificity but
may be helpful in suggestive clinical settings. Better serological tests
are indirect fluorescent antibody test(7) and elisa using specific 56
kda recombinant antigen. In both our children the specific elisa was
positive. Specific tests are preferred wherever possible. Conventional
antibiotics used for treating scrub typhus are doxycycline and
chloramphenicol. Response to these drugs was excellent in the two
children. A therapeutic trial of antibiotics is also warranted if
specific tests are unavailable and the index of suspicion is high.
Macrolides may prove useful in children and pregnant women(8,9). In the
first child, though the intensity of fever was coming down with
roxithromycin, as there was no sufficient data on its effectiveness in
scrub typhus, the child was started on doxycycline.
Diagnosis of scrub typhus and other rickettsial
infections is important, as these are treatable with inexpensive
antibiotics and if untreated can be fatal. Unless there is a high index
of suspicion, it is likely to be missed as the clinical presentation may
mimic other common infections in the tropics.
The authors would wish to acknowledge Dr. Reji Thomas
and Dr. T. Jayakala who were involved in the daily care of the patients.
Contributors: SP was involved in drafting the
paper. EM assisted in confirming and documenting microbiological
diagnosis and modified the manuscript. PDM critically reviewed the
manuscript. He would act as the guarantor for the paper.
Competing interests: None.