A pregnant woman with acute cardiorespiratory failure: dengue myocarditis

In April, 2014, a 29-year-old Vietnamese woman, 31 weeks into her fourth pregnancy, presented to a clinic in Ho Chi Minh City with a 2 day history of fever, dry cough, chest pain, and shortness of breath. She had a history of partial thyroidectomy for hyperthyroidism in 2012, and had had three miscarriages. She took 150 μg thyroxine daily and was a non-smoker. She was initially treated for presumed pneumonia with imipenem. However, her respiratory function deteriorated overnight and she was transferred to the intensive care unit (ICU) at our hospital. On admission she was febrile (38°C), tachycardic (pulse 115 beats per min), and tachypnoeic (respiratory rate 28 breaths per min), with an SpO2 of 94% on 5 L oxygen. Heart sounds were normal but she had bibasal crackles on chest auscultation. Apart from a gravid uterus, abdominal examination was normal. Chest radiograph showed bilateral infi ltrates suggesting pulmonary oedema (appendix). Haemoglobin was 92 g/L, haematocrit 29·2%, total white cell count 8·5 × 109/L, (neutrophil count 7·53 × 109/L and lymphocyte count 0·4 × 10/L), with a platelet count of 134 × 109/L; INR was 1. Urea, electrolytes, liver transaminases, and procalcitonin were normal. Arterial blood gas analysis showed pH 7·49, PaO2 69 mm Hg, PaCO2 30·9 mm Hg, HCO3 23·7 mmol/L, and lactate 1·2 mmol/L. We started oseltamivir and continued imipenem and maintenance fl uids. Her respiratory function deteriorated further (respiratory rate 35 breaths per min, SpO2 85% on 15 L oxygen) so we started non-invasive ventilation with bilevel positive airway pressure (BiPAP) and added vancomycin and azithromycin. ECG showed inverted T waves in the inferior leads (appendix), and troponin I was raised (1·1 μg/L; normal <0·3 μg/L) peaking at 1·6 μg/L the next day, with pro-brain natriuretic peptide 1913 ng/L (normal ≤125 ng/L). Portable ultrasonography showed small bilateral pleural eff usions, but echocardiography was not available. NS1 dengue rapid test was positive and we decided to deliver the baby that day (illness day 4) in view of the likelihood of worsening thrombocytopenia and coagulopathy during the critical period of dengue. A baby girl weighing 2·22 kg was delivered by emergency caesarean section; she needed only supportive care until discharge from the neonatal unit 4 weeks later. The mother, who had been intubated during surgery, returned to ICU and needed a further 24 h of BiPAP. Her platelet count reached a nadir of 25× 109/L on illness day 6 but she had no signifi cant bleeding or shock. She had IgM seroconversion and real-time PCR confi rmed DENV-4. Throat swab was negative for infl uenza A and infl uenza B. Bronchoalveolar lavage and blood cultures were negative. Thyroid function was normal and autoimmune screen was negative. She was well enough to be discharged 8 days after admission, with a diagnosis of acute cardiac failure due to dengue myocarditis. At followup 4 weeks later, she had a normal ECG (appendix) and echocardiogram. Dengue is one of the fastest spreading viral infections and 2·5 billion people now live in endemic areas. Cardiac involvement in dengue can range from myocardial impairment and bradyarrhythmias to fulminant myocarditis. Dengue myocarditis can present at any time during the illness, unlike other severe manifestations that present during the critical phase around defervescence. Cardiac eff ects have rarely been reported in pregnant women with dengue, which might be due to underreporting because of limited diagnostic methods in endemic areas, or misdiagnosis. Dengue is associated with poor maternal and fetal outcomes, but the contribution of cardiac morbidity has not been defi ned. Pregnancy-related plasma volume expansion and raised capillary hydrostatic pressure could exacerbate the cardiovascular complications of dengue. As dengue incidence continues to increase, particularly in young adults, complications in pregnancy are likely to rise. This case highlights the need to consider dengue in patients living in or travelling from endemic areas, presenting with cardiopulmonary failure, particularly in pregnancy.