How to prevent and treat Dengue fever

prevent dengue

How to prevent and treat Dengue fever

Dengue fever is a type of viral fever caused by the RNA virus called dengue virus. Dengue fever spreads from one person to another through mosquito bite.

There is no direct spread from person to person. Infected Aedes aegypti mosquitoes (Asian tiger mosquitoes) spread the disease. Aedes mosquitoes breed in stagnant, clean and fresh water found around our houses.

Aedes mosquitoes usually bite the lower part of our body like legs and foot. They feed mostly on daytime.

How to identify Aedes mosquitoes?

Aedes mosquitoes are small, dark (mostly Black) mosquitoes with white stripes on their bodies and legs. So they are called as Asian tiger mosquitos.

Dengue fever mostly occurs in tropical and subtropical regions, like Asia, Africa, South America and Europe. Dengue fever affects around 2 to 3 billion people around the world.

There are 4 strains of dengue virus.(Dengue virus Strain 1,2,3 and4). If the person is affected by one strain he will have lifelong immunity for that strain and other strains can affect him.

Signs and symptoms of dengue fever

High Fever (Around 104 degree F), severe frontal headache (behind the eyeballs), severe body and joint pain (Break bone fever), nausea, vomiting, fatigue and maculopapular rashes around the face, neck, back and chest are the common symptoms of dengue fever.

In Dengue hemorrhagic fever, bleeding under the skin, conjunctiva, nose or gums can be seen.

In Dengue shock syndrome the blood pressure may drop to dangerously low level. Dengue fever affects many but only people with low immunity (like people with diabetes, AIDs, people on long-term steroids), children and elderly people will develop complications.

Incubation period: The symptoms of dengue fever appear after a period of 3 to 15 days after the mosquito bite.

Pathophysiology

When Aedes mosquito infected with dengue virus bites a person, the virus enters the bloodstream and enters the white blood cells, grow and reproduce inside the cells. The infected cells produce chemicals which increases the body temperature and severe body pain. The chemicals increase the permeability of blood vessels and fluid leaks into the body cavities producing low blood pressure (Dengue Shock Syndrome). Infection of bone marrow reduces platelet count and produces bleeding (Dengue Haemorrhagic Fever).

Tests for Dengue Fever

Complete blood count: White cell count may be reduced.

Platelet count: May be reduced. ( Normal: 1.5 to 4.5 L)

If platelet count falls below 50,000 there will be bleeding tendencies and if it falls below 20,000 platelet transfusion is necessary.

Rapid NS1 test ( Non Structural protein 1 test): Dengue antigen test-done on first 5 days for rapid detection.

IgM and IgG: (dengue virus antibodies)-Done after 5 days of fever.

ELISA: (enzyme-linked immunosorbent assay) is the commonly used test to detect dengue antibodies.

Haemagglutination inhibition test (HI): This test helps to differentiate between primary and secondary infection.

Direct dengue viral detection and culture can be done.

Liver function test and renal function test can be done to rule out liver and kidney involvement.

X-ray chest and ultrasound abdomen to see fluid collection (Pleural Effusion and Ascites). Blood sugar estimation to be done to rule out diabetes.

Treatment For dengue fever

No antiviral drugs available to treat dengue virus. Antibiotics are not effective on dengue virus.

Treatment is supportive care and symptomatic treatment.

Temperature can be brought done by Antipyretics (paracetamol) and tepid sponging.

Nonsteroidal anti-inflammatory drugs like aspirin and ibuprofen to be avoided to prevent bleeding.

Hydrate the body by drinking lots of fluids like water, lemon juice or orange juice. Oral electrolytes can be given.

Treatment for Dengue shock syndrome: Maintain blood pressure by intravenous fluids or plasma or volume expanders.

Treatment for Dengue hemorrhagic fever: If platelet count is very low Platelets can be replaced or blood transfusion can be given.

To increase platelet count drink papaya leaf juice or papaya juice.

Prevention of dengue fever

As there is no antiviral drug for dengue virus, prevention is the only way of controlling the disease.

Vaccination for dengue fever

Now a vaccine called Dengvaxia, approved by World Health Organization is available since 2016 and the vaccine is in use in many countries.

Preventive measures

Prevent mosquito breeding by removing all Aedes mosquitos breeding places like empty discarded tyres, cups, broken pots, broken bottles, coconuts shells etc… from our surroundings. So there won’t be any water collection for mosquitos to breed. Cover all water storing places like water tank, sumps, buckets and vessels. Change the water in all flower washes often.

Antilarval measures: Spray oil or chemicals over open water sources to kill larva or can grow fish which feed on larva.

Prevent mosquito entering houses by fixing mosquitos screens on windows and using mosquito repellents.

Prevent mosquito bite by using long sleeved dresses or sleeping inside the mosquito net.

Mosquito repellent, Mosquito coils and mosquito repellent vaporizers can be used to prevent mosquito bites.

Natural repellents are better as they are less harmful.

Gestational Hypertension

Gestational Hypertension

Gestational Hypertension (pregnancy induced hypertension) 

Gestational hypertension (pregnancy induced hypertension), preeclampsia and eclampsia are commonly encountered medical complications in pregnant women, after 20 weeks of pregnancy. If the woman is already suffering from hypertension it is called chronic hypertension in pregnancy.

These conditions produce high morbidity and mortality in the fetus (baby) and mother.

What is Gestational Hypertension (PIH)?

When a pregnant woman develops high blood pressure (above 140/90 mm of Hg) after 20 weeks of gestation (pregnancy) without both protein in urine and edema (swelling of the face, legs and hands), she is said to be suffering from Gestational hypertension.

hypertension-during-pregnancy

 

What is preeclampsia?

When a pregnant woman, after 20 weeks of pregnancy develops the triad of signs (3 main signs) namely Hypertension, protein in the urine (proteinuria)  and edema, she is said to be suffering from preeclampsia.

Preeclampsia can be mild (when blood pressure is from 140/90 up to 159/119) or severe (when blood pressure is above 160/110 mm of Hg).

What is Eclampsia?

Eclampsia is a complication of severe preeclampsia where the pregnant woman develops convulsions (seizures or through fits).

25% of patients develop convulsions before delivery.

50% may develop during delivery.

25% may have seizures after delivery.

Preeclampsia and eclampsia are together called as Toxemia of pregnancy.

What is HELLP syndrome?

Preeclampsia with haemolysis (destruction of blood), Elevated Liver enzymes and low platelets counts is called HELLP syndrome. It is a complication of preeclampsia.

What are the causes of Gestational hypertension/preeclampsia/eclampsia?

  • First-time pregnancy (nulliparous woman or prime). Can occur in second pregnancy also.
  • Age: Getting pregnant before 18 years or after 35 years.
  • Multiple gestations like twins and triplets.
  • Abnormal placenta.
  • Previous history of Preeclampsia. Having family history of preeclampsia.
  • Heredity.
  • Having other diseases like chronic hypertension, diabetes, chronic kidney disease and high cholesterol levels.

How does the disease develop? (pathophysiology)

When fetal trophoblasts do not invade deep enough into the mothers utrine wall, spiral arteries may not dilate fully. This increases the resistance to blood flow to the placenta. This leads to fetal hypoxia (not enough oxygen and nutrients to the fetus). This leads to the release of antiangiogenic factors and inflammatory mediators. This induces generalized endothelial damage and hypertension.

hypertension-while-pregnant

 

Signs and symptoms of Gestational Hypertension

Gestational hypertension may not show any symptoms. Patients may have a mild headache.

Blood pressure may be above 140/90 mm of Hg. Urine protein will be absent. Edema may be there as it is common in pregnancy.

Signs and symptoms of preeclampsia:

In preeclampsia patients may have a severe headache, blurred vision, fatigue, nausea/vomiting, pain abdomen and giddiness. Edema of nondependent area like face, hands and legs seen.

In severe preeclampsia, blood pressure may be very high (above 160/110 mm of Hg). Along with the above symptoms patients may have reduced urine output, breathlessness (shortness of breath) due to fluid collection in lung tissue, sudden weight gain and liver disorder.

Signs and symptoms of eclampsia

It is a complication of preeclampsia.

Along with the symptoms of preeclampsia, the pregnant woman may have seizures (convulsions). They may be disoriented and at times become unconscious. Sometimes it may be fatal for the baby and mother.

What are the investigations to be done

Tests for Gestational hypertension

Regular Blood pressure monitoring: Blood pressure above 140/90mm of Hg

Routine blood investigations like blood sugar and cholesterol to rule out other diseases.

Urine analysis for protein:  No protein in the urine.

Blood liver and kidney functions: may be normal.

Investigations (tests) for preeclampsia and eclampsia

More frequent blood pressure monitoring.

Blood tests as given above and 24 hours urine protein estimation: more than 300 mg / 24 hours or more than 1+ in a single urine sample.

Frequent blood count and Platelet count to find out thrombocytopenia.

Ultra sound scanning of the uterus to assess’ fetal growth and heart rate.

Ultrasound thorax to find out lung congestion (pulmonary edema) and

Utrine artery Doppler can be done.

Treatment

Delivery of the baby is the only treatment.

Treatment of gestational hypertension (pregnancy induced hypertension)

Salt restricted diet and rest. Mild hypertension is good for the baby. Sudden reduction of blood pressure to be avoided. For severe hypertension anti- hypertension drugs can be given.

Treatment for preeclampsia

Salt restriction and bed rest in lateral position (lying on sides) to avoid the weight of the baby on main blood vessels.

If the baby is mature, plan for delivery.

If blood pressure is very high anti hypertension drugs can be started.

Nifedipine or methyldopa can be given orally. Labetalol can be given intravenously or Hydralazine IV or IM can be given.

Angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers and atenolol are contra indicated.

Magnesium sulfate infusion to be started to prevent seizures.

Treatment of Eclampsia

Magnesium sulfate 4-gram loading can be given intravenously (IV) followed by infusion of 1-3 grams/hour to control seizures or injection diazepam can be given slowly intravenously.

Induce delivery or go for cesarean delivery.

The blood pressure and signs and symptoms of these diseases will disappear within 4 to 6 weeks after the delivery of the fetus.

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