Summary
Highlights
Dengue hemorrhagic fever (DHF) is a severe, potentially fatal form of dengue fever. Dengue fever is an acute febrile disease caused by the dengue virus, transmitted by Aedes mosquitoes. It is also known as 'break bone fever' or 'infectious thrombocytopenic purpura'. DHF is characterized by bleeding diathesis and hypovolemic shock. The viruses are related to those causing West Nile infection and yellow fever.
The pathophysiology of DHF includes an initial phase similar to dengue fever, where the virus is deposited in the skin by the mosquito vector. This is followed by vascular leakage, leading to hemoconcentration and effusions, potentially causing circulatory collapse. If left untreated, DHF can progress to Dengue Shock Syndrome (DSS).
DHF is classified by severity into mild, moderate, and severe. There are also four grades of DHF and DSS. Grade 1 involves fever and non-specific symptoms with a positive tourniquet test or easy bruising. Grade 2 includes spontaneous bleeding in addition to Grade 1 symptoms. Grade 3 shows signs of circulatory failure like a rapid, weak pulse and hypotension. Grade 4 presents profound shock with severe circulatory failure.
Laboratory criteria for diagnosing dengue include dengue virus isolation, immunoglobulin (IgM/IgG) antibody titers, immunohistochemistry, polymerase chain reaction (PCR) for viral genomic sequences, and a complete blood count (CBC). A CBC may show increased hematocrit due to plasma extravasation and decreased platelet count (normal range: 150,000-400,000 per microliter). The guaiac test is also used to detect occult blood.
Early detection is crucial for managing DHF. Treatment includes oral rehydration therapy for moderate dehydration and IV fluid administration for mild to severe dehydration. Blood transfusions or blood products like fresh frozen plasma may be required for internal bleeding or coagulopathy. Patients should avoid aspirin and other NSAIDs as they increase the risk of hemorrhage.
Symptoms of dengue typically appear 4-6 days after infection and last up to 10 days, including fever, nausea, vomiting, rash, and aches. Warning signs include severe abdominal pain, persistent vomiting, rapid breathing, bleeding gums, fatigue, and restlessness. Nursing management involves monitoring blood pressure, managing pain, maintaining vascular access for fluid and blood replacement, reviewing medication regimens to avoid exacerbating bleeding, and managing nosebleeds by elevating the patient and applying ice.
A short quiz reviews key aspects of dengue: the Aedes aegypti mosquito spreads dengue; symptoms usually begin 4-6 days post-infection; untreated DHF can lead to hypovolemic shock; the Trendelenburg position restores blood volume to the head; decreased platelet count is a confirmatory test; dengue incubation is about one week; Grade 1 DHF shows positive tourniquet tests; the guaiac test checks for occult blood; plasma leakage and hemorrhagic symptoms appear shortly after fever breaks; and untreated DHF progresses to dengue shock syndrome.