Friday, July 10, 2009

Feverish Rainy Season

The Monsoon is here.Though it really began pouring down only last week the Fever season started by early June. OPDs are overflowing and it is hard to get a hospital bed.
What kind of fevers are more commonly seen this year?
The usual influenza like upper respiratory tract infection is the commonest but the more serious fever this year is Dengue fever.Chikungunya fever is less common when compared to last year.
Dengue Fever[DF]
Dengue is a mosquito-borne infection that in recent decades has become a major international public health concern. Dengue is found in tropical and sub-tropical regions around the world, predominantly in urban and semi-urban areas.As per current estimates, availability of at least 100 countries are endemic for DF and about 40% of the world population (2.5 billion people) are at risk in tropics and sub-tropics. As per estimates, over 50 million infections with about 400,000 cases of DF are reported annually which is a leading cause of childhood mortality in several Asian countries.

Dengue is transmitted by the bite of an Aedes mosquito infected with any one of the four dengue viruses. Symptoms appear 3—14 days after the infective bite. Dengue fever is a febrile illness that affects infants, young children and adults.
Symptoms range from a mild fever, to incapacitating high fever, with severe headache, pain behind the eyes, muscle and joint pain, and rash. There are no specific antiviral medicines for dengue. It is important to maintain hydration. Use of acetylsalicylic acid (e.g. aspirin) and non steroidal anti-inflammatory drugs (e.g. Ibuprofen) is not recommended.
Dengue hemorrhagic fever (fever, abdominal pain, vomiting, bleeding) is a potentially lethal complication, affecting mainly children. Early clinical diagnosis and careful clinical management by experienced physicians and nurses increase survival of patients.
My Experience
When a patient presents with sudden appearance of high grade fever and headache without congested nose or cough my thoughts are about Dengue fever.If there is severe joint pain and swelling especially of small joints of hand I may consider Chikungunya as the first possibility.
I will then order a Complete Blood Count. A low total WBC count along with low Platelet count make my suspicion of Dengue fever stronger. Chikungunya fever may also have a low WBC count but the Platelets are usually not very low.
I admit the patient if the Platelet count is below 100000 or if the patient looks very sick. Maintaing hydration and blood pressure is most important. I had more than 20 patients with suspected Dengue fever since the beginning of June, but only one had the complication of Dengue hemorrhagic fever.There were no loss of life.

Diagnosis of Dengue fever is mainly by clinical features and not by laboratory methods.By the time the antibody levels rises and is detectable by blood tests the disease would have subsided.

Prevention of Dengue fever is mainly by reducing the mosquito breeding.Aedes breeds primarily in man-made containers like earthenware jars, metal drums and concrete cisterns used for domestic water storage, as well as discarded plastic food containers, used automobile tyres and other items that collect rainwater.
Vector control is implemented using environmental management and chemical methods. Proper solid waste disposal and improved water storage practices, including covering containers to prevent access by egg-laying female mosquitoes are among methods that are encouraged through community-based programmes.
The application of appropriate insecticides to larval habitats, particularly those that are useful in households, e.g. water storage vessels, prevents mosquito breeding for several weeks but must be re-applied periodically. Small, mosquito-eating fish and copepods (tiny crustaceans) have also been used with some success.
Fever season is always a challenge for an Internist like me. I love that challenge. Hope I can rise up to it.

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