Case Reports

Dengue Fever: Two Unexpected Findings

These two case reports highlight the importance of maintaining a high index of suspicion for dengue in febrile patients with a history of recent travel to countries where this disease is endemic.

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Dengue fever is the most commonly transmitted arboviral disease in the world, affecting an estimated 2.5 billion people who live in areas endemic to the virus. This exposure yields an annual incidence of 100 million cases of dengue, which translates into 250,000 cases of hemorrhagic fever. With an expanding geographic distribution and increasing number of epidemics, the World Health Organization (WHO) has classified dengue as a major public health concern.1 Enhanced globalization and changing climate patterns have resulted in a dramatic increase in the incidence of dengue in both North and Central America. Aggregate North and Central American data from 2010 to the present revealed over 1.7 million cases of dengue, nearly 80,000 of which were severe, and 747 deaths.2 Based on these statistics, dengue fever should be considered in the differential diagnosis of febrile ED patients in the developed world who had a history of recent travel. We present two cases that highlight the complexity of diagnosis and novel complications associated with dengue fever.

Case Reports

Case 1

A 24-year-old man presented to the ED with a 4-day history of intermittent fever of up to 102.02°F, which was accompanied by chills, myalgia, and rigors. The patient stated that he had visited Vietnam, Thailand, Indonesia, and Malaysia 8 days prior to presentation, and had experienced mosquito bites daily throughout his travels. He further noted that his symptoms had improved on day 3 of his illness, but acutely worsened on day 4, which prompted him to visit the ED. The patient’s primary complaint was a severe retro-orbital headache, fever, and one episode of epistaxis.

On physical examination, the patient had conjunctivitis and hepatosplenomegaly, but otherwise appeared well. His laboratory evaluation was significant for leukopenia (white blood cell [WBC] count, 2.40 x 109/L), thrombocytopenia (platelet count, 123 x 109/L), and a positive mononuclear spot test. Both dengue immunoglobulin G (IgG) and immunoglobulin M (IgM) tests sent from the ED were negative. Based on the patient’s thrombocytopenia and epistaxis, as well as concerns that the patient was entering into the critical phase of dengue fever, he was admitted to the inpatient hospital for observation.

The patient’s course improved during his stay with symptomatic treatment and blood-count monitoring, and he was discharged home on hospital day 3. He followed up at our hospital travel clinic the day after discharge; a repeat dengue IgM test taken during this visit came back positive.

Case 2

A 51-year-old man presented to the ED with a 3-day history of intermittent fever and diffuse myalgia. He reported chills, night sweats, and the feeling of abdominal fullness. He denied nausea, vomiting, or changes in the character of his stool. He had no known sick contacts, but reported he had traveled from the Philippines 3 days prior to presentation and that his symptoms had developed en route to the United States. The patient also denied any known tick, mosquito, or animal exposures. He said he had treated his symptoms with acetaminophen and nonsteroidal anti-inflammatory drugs. Prior to his arrival at the ED, he had twice presented to a walk-in clinic earlier that day. Repeated laboratory testing at the ED showed a decrease in WBC count from 42.0 x 109/L to 31.0 x 109/L, as well as a declining platelet count from 123 x 109/L to 87 x 109/L. On physical examination, the patient was ill-appearing, diaphoretic, and had a temperature of 100.6°F. His vital signs were otherwise within normal limits.

With the exception of a mild diffuse petechial rash on the patient’s thighs bilaterally, the physical examination was unrevealing. A tourniquet test (TT) to assess capillary fragility was performed at bedside, and yielded a positive result (Figure 1). Work-up further demonstrated a declining WBC of 2.70 x 109/L and declining platelet count of 65 x 109/L.

A polymerase chain reaction (PCR) test confirmed a diagnosis of dengue, with a positive dengue type-4 (DEN-4) serotype detection. Supportive care was initiated, and the patient was admitted to the inpatient hospital for continued treatment. He was discharged home on hospital day 5; however, he returned to the ED later that day with increasing headache and left flank pain. Work-up included axial and coronal computed tomography scans of the abdomen and pelvis, which revealed hematuria and a left upper pole renal infarction surrounded by mild perinephric fat stranding (Figure 2a and 2b) with maintenance of left renal artery/vein patency.

The patient was admitted to an inpatient floor, where symptomatic management was employed. He underwent unrevealing bubble echocardiography and lower extremity Doppler ultrasound imaging, and anticoagulation therapy was initiated per a consultation with hematology services. The patient was discharged home in improved, stable condition on hospital day 8.

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