Abstract
Scrub typhus is a serious public health problem in the Asia Pacific region. Early diagnosis and treatment can prevent complications and mortality. Splenomegaly in isolated scrub typhus is mostly mild or subclinical and rarely massive. We report an adolescent boy with scrub typhus presenting with fever, massive splenomegaly and severe anemia. Clinicians should be aware of atypical presentations of scrub typhus, which is easily treatable with minimal investigations.
Case report
A 13-year-old boy presenting with 7-day history of fever, dyspnoea and abdominal distension had severe pallor and hepatomegaly. The spleen was massively enlarged, measuring 13 cm below the left costal margin, crossing the umbilicus and was firm in consistency. Supplemental oxygen with nasal prongs at 2L/min was started. Severe anaemia associated with massive splenomegaly prompted investigations for malaria, scrub typhus, enteric fever, underlying haemolytic anaemia, storage disorders and haematological malignancy. Empirical treatment with ceftriaxone and doxycycline was started.
Our investigations, apart from a severe microcytic hypochromic anaemia (Hb 55g/L), revealed corrected reticulocyte count of 1.5%, total leucocyte count 6.66 x109/L (55% neutrophils), platelet count 311 × 109/L, erythrocyte sedimentation rate 27 mm in the first hour, serum albumin 2.4g/L, total bilirubin 41.04µmol/L (conjugated 25.65µmol/L), mild transaminitis, lactate dehydrogenase 1.19µkat/L and C-reactive protein 24mg/dL. Serum ferritin was normal, total iron binding capacity low, direct Coombs test negative and high-performance liquid chromatography for haemoglobin variants were normal. Malarial antigen and smear, NS1 antigen and IgM antibodies for dengue, and COVID real-time polymerase chain reaction tests were negative. IgM antibodies for scrub typhus were positive (index value: 8.64, Ref.: < 0.9).
Abdominal ultrasound confirmed advanced hepatosplenomegaly (liver 14 cm, spleen 15 cm), a distended gall bladder with pericholecystic fluid, mild to moderate ascites and bilateral pleural effusions.
Following admission to our paediatric intensive care unit, transfusion with packed red cells was commenced. He was afebrile by the third day of admission, his respiratory distress had improved, and the spleen size had reduced to 10 cm. Follow-up examination at 4 weeks showed further reduction in splenomegaly and by 8 weeks it had completely resolved.
Discussion
Scrub typhus, a serious public health problem in the Asia Pacific region, may present diversely with fever, headache, myalgia, generalised or regional lymphadenopathy to meningoencephalitis, acute respiratory distress syndrome and multiple organ dysfunction syndrome with hepatic and renal failure.1,2 Early diagnosis and treatment can prevent complications and mortality. Eschar, when present, is a valuable clinical clue, but is found relatively rarely.
Splenomegaly in isolated scrub typhus is mostly mild or subclinical and rarely massive. 2 Standard descriptions of massive splenomegaly indicate its being palpable >8 cm below the costal margin, its longest craniocaudal diameter being > 20 cm, or its drained weight >1000 g.3,4 The definition and grading of splenomegaly in children is not standardised. 5
Infections are the commonest cause for splenomegaly. 3 Enhanced work in antigen clearing and antibody production by increase in reticuloendothelial cell number and increase in immune functions lead to splenomegaly. Visceral leishmaniasis and hyper-reactive malarial splenomegaly can cause massive splenomegaly but myeloproliferative disorders (chronic myeloid leukaemia, polycythaemia vera, essential thrombocythaemia, osteomyelofibrosis) or haematological disorders (osteopetrosis, thalassaemia) are more common causes. 3 Massive splenomegaly in scrub typhus is rare; previous reports include a young adult who, as our patient, dramatically responded to doxycycline. 6
Scrub typhus remains an underdiagnosed cause of undifferentiated fever owing to lack of awareness, a low index of suspicion and lack of access to adequate and effective serological assays. This case highlights that massive splenomegaly may indeed be a presenting manifestation of scrub typhus. Awareness of atypical presentations of scrub typhus and a high index of suspicion may avoid expensive investigations and lead to timely diagnosis and cure.
Footnotes
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
