Can You Solve This Case Of Tropical Fever?
December 23rd, 2022 by INMED
Maria, the seven-year-old girl in this photo, presents to you at the Clinical Evangelica Morava on the remote western coast of Honduras. Her parents explain that five days ago she suddenly developed fever, vomiting, severe headache, and pain on moving her eyes. Several other children in the neighborhood have been similarly ill since the onset of the rainy season with its customary heat and mosquitoes.
On physical examination you note that Maria is lethargic, has generalized lymph node enlargement with clear lungs and a slow heart rate relative to her fever of 39 degrees. She has a fine rash on her extremities. You quickly perform thick and thin blood smears with Giemsa stain, but you do not identify any ring-like Plasmodium parasites within red blood cells that would suggest malaria.
Your initial differential diagnosis is broad: influenza, dengue, typhoid fever, mononucleosis, malaria with negative blood smear. You initiate intravenous fluids and antipyretics. Over the next hours Maria develops hypothermia, severe abdominal pain, persistent vomiting, decreased mental status, and bleeding from her gums and nose. You now suspect the Maria is suffering from dengue – an arbovirus infection.
Which ONE of the following is a characteristic of severe dengue fever?
A. Leukocytosis with increased band forms
B. Increased urinary output
C. Abnormal vascular permeability with spontaneous bleeding
D. Predictable improvement in response to gamma globulin infusion
E. Decreasing hematocrit
Explanation: Abnormal vascular permeability with spontaneous bleeding, fever, and low platelet count are key criteria for diagnosis of severe dengue fever. Leukopenia (low white blood cell count), increasing hematocrit, and decreased urinary output commonly accompany severe dengue fever. Gamma globulin is of no therapeutic benefit. The correct answer is C.
You continue to treat Maria’s hypotension and shock, taking care to not administer aspirin or nonsteriodal anti-inflammatory drugs (NSAIDs) as they may increase bleeding tendency. Vitamin K supplementation may be useful given her coagulopathy, but the Clinica has none in stock. Meanwhile, Maria’s parents politely but persistently press you for information about her illness.
Of the following statements about dengue fever which ONE is NOT true?
A. Dengue vaccine is indicated for administration to people living in regions with high mosquito density.
B. The vector for dengue is the Aedes aegypti mosquito.
C. Dengue most commonly occurs in Southeast Asia and Latin America.
D. Treatment is essentially supportive with particular attention to hemodynamic status.
E. Infection may progress to complications that include hemorrhage and shock.
Explanation: WHO recommends the dengue vaccine CYD-TDV for people ages 9 to 45—only in geographic settings with a high burden of dengue disease and only be given to persons with confirmed prior dengue virus infection. The vector for dengue virus is the Aedes aegypti mosquito, which feeds during the early morning and late afternoon. The mosquito is adapted to the human habitat, often bites indoors, and breeds in small quantities of water. Dengue is distributed throughout the tropics, causing sporadic cases or large epidemics, especially in Southeast Asia and Latin America. Commonly recognized complications include thrombocytopenia, bleeding, and hypovolemia. Treatment is supportive, with particular attention to hematocrit, blood pressure and urine output, and adequate hydration. The correct answer is A.
World Health Organization. Dengue and severe dengue. http://www.who.int/mediacentre/factsheets/fs117/en/. Accessed January 1, 2023.
Dengue fever is a classic disease of poverty – one associated with insects and poor housing, and one that calls for broad social development as well as medical interventions. The heartening response of many to Maria’s illness is to offer their personal time and talent to protect those like her. Together let’s continue to emphasize interventions that empower marginalized communities to combat poverty and to care for their own.