| ID | 181 |
|---|---|
| Name | DENGUE FEVER |
| Cause | |
| Signs Symptoms | |
| Diagnosis | Diagnosis: 1. Complete blood count- leukopenia, thrombocytopenia (hemorrhagic fever). 2. Isolation of dengue virus in the blood during acute phage (collecting serum sample within 5 days after the onset of illness). 3. Serological test for detecting dengue viral anti-body litre (IgM ELISA test)- this may detect cross-reacting antibodies from other flavi-viruses. |
| Investigations | |
| Management | Management: There is no specific treatment for dengue fever, only symptomatic & supportive therapies are given. Classic dengue fever: 1. Fever & pain- paracetamol is the drug of choice, but in severe aching, opiates may also be given. Aspirin (& other NSAIDs) must not be given for their antiplatelet effect. 2. Plenty of oral fluids should be given. Dengue hemorrhagic fever: 1. Immediate hospitalization. 2. Fever & pain- treatment as above. 3. In mild hemorrhagic fever- oral rehydration may be enough; i.v fluid may be given if necessary. 4. In severe hemorrhagic fever- if there is any feature of shock or elevated hematocrit value, patient should be treated by isotonic i.v fluid immediately for volume replacement; crystalloid (ringer’s, lactate or normal saline) or colloid preparations (viz. dextran) in more refractory cases may also be administered. Fresh whole blood transfusions are preferable in significant bleeding; fresh frozen plasma is indicated in massive bleeding due to any coagulation defect; in cases of bleeding due to thrombocytopenia, concentrated platelets are more helpful to be given if available. 5. Regular recording of vital signs, |
| Introduction | Dengue is a viral febrile disease of humans, caused by a flavivirus. The main carrier of this viruses is a mosquito, known as Edes egypti, and is transmitted by the daytime-biting specially in the summer season. After infection, humans are usually infective in the first three days of the illness- that is the viremice stage of the disease. The healthy Edes mosquitos become infective about two weeks after feeding on an infected individual and persist as carrier for the rest part of their lives. There are four antigenic serotypes (Den-1, Den-2, Den-3 & Den-4) of dengue virus, but all are producing a similar clinical syndrome. After infection of an individual, the immunity develops, which is life-long for the same serotype of the virus infected & only a few months for the other serotypes. The usual incubation period is 7-10 days, but it can be as short as 2 days and as long as 15 days. This occurs endemically in the tropical & subtropical countries specially in the South-east Asia & epidemically in the other zones of the world. |
| History | |
| Etiology | |
| Clinical Features | Clinical feature: Many times dengue virus causes a subclinical, asymptomatic or very mild infection. In other cases, there may be a classic pattern of dengue fever with acute onset, or a hemorrhagic presentation with occasional shock syndrome. Classic dengue fever: 1. There may be a prodromal phase of malaise & headache for two days. 2. Then, an acute onset of high fever with headache, backache & arthralgias, presenting as severe aching (‘breakbone’ pain), facial flushing, deep eye (retrobulbar) pain (worsening on movement) & conjunctival secretion, accompanied by sore throat, prostration, depression, lymphadenopathy & relative bradycardia. 3. Fever- acute & sudden onset of high fever with chills; fever is usually continuous or saddleback pattern and biphasic, initial phase lasts for 3-7 days, then after a remission period of few hours to 2 days, second phase of fever appears & lasts for 1-2 days. 4. Rash- appears in about 80% of patients. Initially, transient macular rashes appear in the first 1-2 days, then followed by maculopapular, morbilliform or scarlatiniform, or petecheal rashes from 3-5th day. It usually appears first on the dorsum of the hands and feet and then spreads to the arms, legs, trunk, and even to the neck but rarely to the face, & lasts for 2 hours to a few days, followed by desquamation. 5. During remission or convalescent period, severe fatigue & a feeling of unwell with depression are common for several weeks. Hemorrhagic dengue fever: It is the severe form of dengue fever, the cause of which is not clear, but thought that, two or more sequential infections with different dengue serotypes are responsible for this serious consequences of infection with development of some autoimmune reaction. It is also thought that, the severity may be due to an anamnestic response to infection with serotype-2. 1. It usually occurs in children but may also occur in adults. 2. There may be a mild start with symptoms like upper respiratory tract infection, which is then followed by an abrupt onset of hemorrhage into the skin, ear, nose and gums, & hematemesis and melena. 3. In the cases of severe hemorrhagic fever hypotension and circulatory failure are the usual consequences with features of a ‘capillary leak syndrome’ leading to developmant of shock, known as ‘dengue shock syndrome’. 4. On laboratory investigation, most significant and suggestive findings are thrombocytopenia & hemoconcentration. |
| Preventions | Prevention: 1. Isolation of the patient, & treatment under a mosquito net. 2. Control of Edes mosquito by- a. Abolishing the breeding places by an integrated approach of environmental sanitation and biological control. b. Destroying adult mosquitos by spraying insecticides. c. Avoiding edes mosquito bites at day-time, specially in the peak feeding period i.e in the morning for several hours & in the late afternoon for several hours, by using mosquito net or by using repellents containing DEBT (less then 30%) on the exposed skin or by using mosquito coil. 3. Dengue vaccine- a live attenuated tetravalent dengue vaccine is at an advanced stage of development, but yet not available for clinical use. |
| Treatment | |
| Complications | |
| Prognosis | |
| Types | “types of dengue fever: Clinically two types of dengue fever are recognised- 1. Classic dengue fever 2. Hemorrhagic dengue fever |
| Classification | |
| Observation | |
| Pathology |
© Pakistan Drug Directory. All Rights Reserved.
Designed By: Pakistan Drug Directory Team