Abstract
Scrub typhus may be associated with a myriad of signs and symptoms. We report the case of a 41-year old male with complete heart block, which resolved with prompt initiation of treatment.
Introduction
Scrub typhus, also called as tsutsugamushi disease, is a febrile illness caused by Orientia tsutsugamushi from the Japanese word tsutsuga (dangerous), mushi (bug). 1 It is a small gram-negative, obligate intracellular organism whose polysaccharides have an antigenic similarity to proteus OX-K. This is thus used in the serological diagnosis. Scrub typhus was first described in detail by Hashimoto from Japan in 1810. 2 It is endemic to a part of world known as the “tsutsugamushi triangle”, which extends from northern Japan and far-eastern Russia in the north, to northern Australia in the south, and to Pakistan and Afghanistan in the west 3 In India, rickettsial infections have been recognised from the states of Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Rajasthan, Assam, West Bengal, Maharashtra, Kerala and Tamil Nadu. 4
Scrub typhus often presents as fever with little to distinguish it clinically from other co-endemic diseases such as typhoid, leptospirosis, and dengue. The presence of an eschar supports the diagnosis but is variably present. Myocarditis in scrub typhus has been rarely reported in recent decades. 5 It is usually subclinical, but may be fatal because of congestive heart failure or severe arrhythmia. Signs of cardiac dysfunction, including minor electrocardiographic abnormalities such as first-degree heart block and inverted T waves can appear. In patients who develop myocarditis, there can be a gallop rhythm, poor-quality heart sounds and systolic murmurs. 6 Adequate treatment can result in complete recovery.
Case report
A 41 year-old male presented with fever and dyspnoea of two days’ duration and then developed an altered mental status the day prior to admission. There was no history of headache or vomiting. He had no past medical history of cardiovascular disease, medication intake, illicit drug abuse, hypertension nor diabetes.
On examination he was normotensive (110/80 mm Hg), bradycardic (22 beats per minute), tachypnoeic (rate 30 breaths/min), and hypoxic (saturation on room air: 61%). He was irritable and disoriented. He had fine rales throughout both lung fields.
He was consequently intubated and placed on mechanical ventilation in the intensive care unit.
Laboratory testing revealed a leukocytosis (16 × 109/L) with 80% neutrophils, 19% lymphocytes and 1% monocytes, and anaemia (Hb 120 g/L and thrombocytopenia (platelet count 30 × 109/L). The creatinine kinase-myocardial band (CK-MB) was 72 ng/m (normal = 0–4.88 ng/mL) and his blood urea nitrogen level was 0.16 g/L (normal = 0.08–0.2 g/L).
The Scrub typhus IgM serology by immune-fluorescence was positive with a titre of 1:512. An electrocardiogram showed complete heart block with severe bradycardia (Figure 1). A chest radiograph revealed bilateral diffuse non-homogenous lung infiltrates predominantly in the right middle and lower zones (Figure 2).
Electrocardiogram showing complete heart block.
Chest X-Ray showing bilateral diffuse non-homogenous infiltrates mainly in the right middle and lower zones of the lungs.
scrub typhus complicated by myocarditis with third degree atrioventricular block, respiratory distress and febrile encephalopathy was diagnosed. Treatment with intravenous doxycycline was commenced; a temporary pacemaker was inserted. By 24 h, the complete heart block had reverted to normal sinus rhythm. After five days of admission, he was extubated, a fresh chest radiograph showed significant radiological improvement. After observation for an additional three days in the general ward, he was discharged in good, stable condition.
Discussion
The diagnosis of scrub typhus is based on patient exposure history, clinical findings and results of serologic testing. 7 Scrub typhus is treatable simply with antibiotics, although a delay in diagnosis may lead to severe complications such as meningoencephalitis, upper gastrointestinal bleeding, pneumonia, acute kidney injury, myocardial infarction and stroke, and multiple organ failure, with significant morbidity and mortality. 8
Reported cardiovascular complications include myocarditis, arrythmias, pericardial effusion and congestive cardiac failure. Myocarditis may present with a wide range of clinical manifestations, from nonspecific symptoms such as fever, myalgia, palpitations and exertional dyspnoea to fatal complications of cardiogenic shock and sudden cardiac death. 9 The main pathologic consequences of scrub typhus are vasculitis, perivasculitis, with cellular infiltrates primarily of lymphocytes and plasma cells, with interstitial haemorrhages and oedema. 10 Cardiomegaly and congestive heart failure may result. 11 Rhabdomyolysis, and myocarditis may result in acute heart failure,5,12 but complete heart block is rare. Nonetheless, a poor outcome can be prevented if timely diagnosis is made and treatment is started promptly.
