SCRUB TYPHUS PRESENTING AS ATYPICAL PNEUMONIA

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Health Sciences:An Open Access Peer Reviewed E-Journal. 2012 Vol.1, Issue 1, April - June

SCRUB TYPHUS PRESENTING AS ATYPICAL PNEUMONIA

Sajan Christopher MD, Department of Medicine andK. Sreekanthan MD,

Department of Infectious Diseases, Government Medical College,

Thiruvananthapuram 695011, India

Abstract

Scrub typhus is being increasingly reported in India. It is highly endemic

in suburban regions of Thiruvananthapuram. It should be considered in

the differential diagnosis of patients with acute febrile illness, including

those with altered sensorium, pneumonitis, atypical pneumonia, acute

respiratory distress syndrome (ARDS), thrombocytopenia, and

abnormalities in liver function tests,. We report a case of scrub typhus

presenting as atypical pneumonia highlighting the wide variation in

clinical presentations. A thorough knowledge of the clinical features of

scrub typhus including its complications and its varied presentations is

important for providing early appropriate life saving empiric treatment

for patients.

Introduction

Scrub typhus is an acute febrile illness caused by Rickettsia

tsutsugamushi. Human beings usually get infected when they

accidentally encroach upon the mite infested areas, known as mite

islands mainly in rural and sub-urban areas.1 Mortality due to the disease

is 7- 30 %.2 Scrub typhus is grossly under diagnosed in India due to its

non-specific clinical presentations, limited awareness and low index of

suspicion among clinicians. The natural reservoir of rickettsial infections

is the adult mite from which the organism passes to the larva by trans-

CASE REPORT: Page 1 of 9 Kerala University of Health Sciences


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ovarian transmission.

1

The larval mites usually feed on the wild rats ofthe sub- genus Rattus.

Clinicians should be aware of this condition during the outbreaks of many

fevers such as Dengue fever, Chikungunya fever, Leptospirosis and other

viral fevers. The infection manifests clinically as high grade fever not

subsiding with antipyretics. The typical rash and eschar may not always

be present.3 Most often there will be generalized or localized, tender

lymphadenopathy.2 Severity varies from sub-clinical illness to severe

illness with multi-organ system involvement, which can be serious

enough to be fatal, unless diagnosed early and treated.1

Case report

A 45 year old male, a manual labourer presented with complaints of high

grade continuous fever of 10 days duration, associated with head ache

and myalgia. He had cough with mucoid sputum for the past 5 days. Hedid not have dyspnoea. He was a native of Aruvikkara in

Thiruvananthapuram district, a highly endemic zone for scrub typhus. He

was on in-patient treatment for 6 days in a local hospital where he

received injections of Cefotaxim and Azithromycin with no relief from

symptoms. Because of persistent fever and cough as well as radiological

evidence of right basal pneumonitis, he was referred to Government

Medical College, Thiruvananthapuram as a case of right lower lobepneumonia.

On examination at the medical college, patient was found to be febrile.

His pulse rate was 100/min, and blood pressure was 120/70mmHg. There

was significant muscle tenderness. He did not have any skin rashes or

signs of jaundice. There were no palpable lymph nodes. Respiratory



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system examination revealed a respiratory rate of 36/min with bilateralbasal crepitations, more in the right lung. Other systems were within

normal limits.

Blood counts revealed a total leucocyte count of 12,400/l with 50%

neutrophils, L- 45% lymphocytes, and 5% eosinophils. Eruthrocyte

sedimentation rate was 32mm/Hr. Non-homogenous opacities were seen

in the x-ray of the chest, in the lower zone on both sides, more on right

side.

Course of the patient in the hospital

The patient was provisionally diagnosed to have leptospirosis and was

given injections of crystalline penicillin. During a detailed general

examination an ulcer (eschar) of < 3mm size was observed in the left

inguinal region. There were also enlarged mildly tender lymph nodes in

the inguinal region on both sides. The diagnosis was revised to scrubtyphus infection and penicillin therapy was discontinued. He was

prescribed to take Doxycycline.

Results of renal function tests were normal. Serum bilirubin level was

1.7mg%, SGOT level was166U/L, SGPT level was 126U/L, Serum alkaline

phosphatase level was 80U/L, serum sodium level was 138mEq/L and

serum potassium level was 3.4mEq/L. C- reactive protein level in the

serum was 2.8mg/L. Electrocardiogram was normal. Leptospira antibodytest done in the second week was negative. Weil Felix test was done on

the 14th day after the start of symptoms. Results revealed Proteus OX

K:1/80, Proteus OX 2:1/20 and Proteus OX19:1/20.

Patient was afebrile by 2 days after starting treatment with doxycycline;

other symptoms also subsided. He was discharged on the 6th day after



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admission. Lung opacities were absent in the x-ray chest of the patientat the time of discharge.

Discussion

The clinical and laboratory features of scrub typhus are notoriously non-

specific. The painless chigger bite can occur on any part of the body but

it is often located in areas that are hard to examine such as the genital

region or axilla.2 An eschar forms at the bite site in about half of primary

infections which begin as small papules, enlarge, undergo central

necrosis and acquire a blackened crust to form lesions resembling a

cigarette burn.2 The fever starts abruptly and is of high grade. Severe

headache, apathy, pain in skin and other muscles are associated

symptoms. Characteristically, generalized lymphadenopathy and hepato-

splenomegaly are seen in the patients.4 The characteristic rash and

eschar may not be always present.3

Non-specific lung infiltrates with predilection to the lower zone have

been described in scrub typhus.5 Our patient presented with high fever

and features of atypical pneumonia, which was confirmed in the chest x

ray. Previously described complications in patients include interstitial

pneumonitis, atypical pneumonia, hepatitis, myocarditis,

meningoencephalitis, disseminated intravascular coagulation and multi

organ failure.6, 7

Laboratory diagnosis of scrub typhus is based on serological and

molecular diagnostic tests. Weil felix test has a low sensitivity and

specificity but may be helpful in suggestive clinical settings.8 It is

desirable to demonstrate a rise in titer of antibodies for the diagnosis of

scrub typhus.9 A four fold rise in agglutinin titers in paired sera is

diagnostic.10 Better serological tests are indirect fluorescent antibody



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test and enzyme linked immunosorbent assay (ELISA) using specific 56kDa recombinant antigen.11

Antibiotics conventionally used for treating scrub typhus are doxycycline

and chloramphenicol.12 Therapeutic trial with antibiotic therapy is also

warranted if specific tests are unavailable and the index of suspicion is

high.8 Macrolides may prove useful in children and pregnant women. 13, 14

References

1. Vivekanandan M, Mani A, Priya YS, Singh AP, Jayakumar S, Purty S.

Outbreak of scrub typhus in Pondicherry. J Assoc Physicians India

2010;58:24-8.

2. Mahajan SK, Bakshi D. Acute reversible hearing loss in scrub typhus. J

Assoc Physicians India 2007;55:512-4.

3. Mathai E, Rolain JM, Verghese GM, Abraham OC, Mathai D, Mathai M,

et al. Outbreak of scrub typhus in southern India during the cooler

months.Ann N Y Acad Sci 2003;990:359-64.

4. Mahajan SK. Scrub typhus.J Assoc Physicians India 2005;53:954-8.

5. Choi YH, Kim SJ, Lee JY, Pai HJ, Lee KY, Lee YS. Scrub typhus:

radiological and clinical findings. Clin Radiol 2000;55:140-4.

6. Saah AJ. Orientia tsutsugamushi (Scrub Typhus). In: Mandell GL,

Bennet JE, Doalin R (editors). Principles and Practice of Infectious

Diseases. Philadelphia: Churchill Livingstone 2000; p. 2056-7.



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14. Lee KY, Lee HS, Hong JH, Hur JK, Whang KT. Roxithromycin

treatment of scrub typhus (tsutsugamushi disease) in children. Pediatr

Infect Dis J 2003;22:130-3.

Figure 1. Photograph showing eschar in the left inguinal region



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Figure 2. X-Ray chest taken before admission



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Figure 3. X-Ray chest on follow up


SCRUB TYPHUS PRESENTING AS ATYPICAL PNEUMONIA

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