Dengue Fever

Reviewed by Dr Bipin B. 

Introduction

Dengue fever is a viral illness that has garnered increasing attention in recent years due to its prevalence in various parts of the world. This comprehensive guide aims to provide a detailed understanding of dengue fever in simple language, making it accessible to everyone. By the end of this guide, you’ll be well-informed about the causes, symptoms, prevention, and treatment of dengue fever.

What is Dengue Fever?

Dengue fever, commonly called dengue, is a viral infection caused by the dengue virus. This virus is primarily transmitted to humans through the bites of infected female mosquitoes, with the Aedes aegypti mosquito being the main culprit. Dengue fever is especially prevalent in tropical and subtropical regions worldwide, including parts of Southeast Asia, the Pacific Islands, the Caribbean, Central and South America, and even some southern regions of the United States.

The Dengue Virus

Types of Dengue Virus

To better understand dengue fever, it’s essential to recognize four distinct serotypes of the dengue virus: DENV-1, DENV-2, DENV-3, and DENV-4. Each of these serotypes can cause dengue fever, and individuals can be infected with multiple serotypes over their lifetime. Importantly, infection with one serotype doesn’t provide immunity against the others. In some instances, subsequent infections with different serotypes can lead to more severe symptoms, a phenomenon known as antibody-dependent enhancement (ADE).

Transmission

How is Dengue Transmitted?

Understanding how dengue is transmitted is crucial for prevention. Dengue primarily spreads to humans through the bite of infected female Aedes mosquitoes, with Aedes aegypti being the most notorious carrier. These mosquitoes are most active during the early morning and late afternoon, which is why it’s essential to take preventive measures during these periods to reduce the risk of mosquito bites.

Person-to-Person Transmission

While mosquito bites are the primary transmission mode, it’s worth noting that in rare cases, the dengue virus can be transmitted through blood transfusions, organ transplants, or from a pregnant mother to her baby during childbirth or breastfeeding. Such instances highlight the need for rigorous screening and safety measures in healthcare settings.

Symptoms of Dengue Fever

What Are the Symptoms?

Dengue fever can manifest in a range of severity, with some individuals showing no symptoms at all. However, common symptoms of dengue fever include:

1. High Fever: Dengue typically begins with a sudden, high fever, often reaching temperatures as high as 104°F (40°C).
2. Severe Headache: Intense headaches are a hallmark of dengue and are frequently described as feeling like one’s bones are breaking.
3. Pain Behind the Eyes: Many dengue patients experience pain or discomfort in their eyes, contributing to the colloquial term “breakbone fever.”
4. Joint and Muscle Pain: Severe joint and muscle pain, which has led to the nickname “dengue fever.”
5. Rash: A rash may appear a few days after the onset of fever. While it’s usually mild, it can be itchy and bothersome.
6. Bleeding: In some instances, dengue can cause bleeding from the nose, gums, or under the skin. Severe bleeding is a critical symptom and requires immediate medical attention.
7. swollen gland
8. Nausea
9. Vomiting

9 Warning Signs of Severe Dengue

While most cases of dengue fever are mild and can be managed at home with rest, fluids, and over-the-counter pain relievers like acetaminophen, it’s essential to recognize the warning signs of severe dengue:

• Severe Abdominal Pain
• Persistent Vomiting
• Rapid Breathing
• Fatigue or Restlessness
• Blood in Vomit or Stools
• bleeding gums or nose 
• Irritability
• being very thirsty
• pale and cold skin

If you or someone you know experiences any of these warning signs, it’s crucial to seek medical attention promptly.

Diagnosis

How is Dengue Diagnosed?

Laboratory tests are crucial for diagnosing and confirming cases of dengue fever. These tests help healthcare professionals determine whether a patient has been infected with the dengue virus and whether it is a recent or previous infection. Here, we’ll provide detailed information on common laboratory tests used to diagnose dengue fever, including the NS1 antigen test, IgM antibody test, and IgG antibody test:

• NS1 Antigen Test (Non-Structural Protein 1 Antigen Test)What is it? The NS1 antigen test is a diagnostic test that detects the presence of a specific viral protein called NS1 in a patient’s blood. NS1 is produced by the dengue virus early in the course of infection, usually within the first few days after symptoms begin.
• How it works: A blood sample is collected from the patient, and the NS1 antigen is detected using a rapid test or an enzyme-linked immunosorbent assay (ELISA) in a laboratory setting.
• Purpose: The NS1 antigen test is valuable for early diagnosis of dengue fever, especially during the initial stages of infection when viral RNA levels might not be detectable.
• Interpretation: A positive NS1 antigen test result indicates an active dengue infection. However, it does not provide information about the specific dengue serotype causing the infection.

1. IgM Antibody Test (Immunoglobulin M Antibody Test)

• What is it? The IgM antibody test is a blood test that detects the presence of IgM antibodies produced by the body in response to a recent dengue infection.
• How it works: A blood sample is collected, and the presence of IgM antibodies against the dengue virus is measured in a laboratory.
• Purpose: This test helps determine whether a patient’s symptoms are due to a current or recent dengue infection, typically within the past few weeks.
• Interpretation: A positive IgM test result suggests a recent dengue infection. However, it does not specify the dengue serotype responsible for the infection. It’s important to note that IgM antibodies can persist in the bloodstream for several months after recovery.

1. IgG Antibody Test (Immunoglobulin G Antibody Test)

• What is it? The IgG antibody test is another blood test that detects the presence of IgG antibodies, which are produced by the immune system in response to a dengue infection.
• How it works: A blood sample is collected and tested to determine the level of IgG antibodies against the dengue virus.
• Purpose: The IgG antibody test helps confirm a past dengue infection and can indicate whether an individual has developed immunity to a specific dengue serotype.
• Interpretation: A positive IgG test result suggests a previous exposure to the dengue virus. Elevated IgG levels may indicate immunity to that specific serotype. However, a positive IgG result does not provide information about the timing of the infection.

Combining NS1, IgM, and IgG Tests

In practice, healthcare professionals often use a combination of these tests to diagnose and confirm dengue fever cases:

• Early Stage: During the early stage of infection, the NS1 antigen test is valuable for rapid diagnosis.
• Later Stage: As the infection progresses, IgM antibodies become detectable and can be used to confirm a recent infection.
• Past Infections: IgG antibody tests can help determine whether an individual has been previously exposed to the virus and whether they have developed immunity to a specific serotype.

It’s important to consult with a healthcare provider for proper interpretation of test results and to ensure accurate diagnosis and management of dengue fever. Additionally, the availability and use of these tests may vary by region and healthcare facility. Early diagnosis and appropriate medical care are essential for managing dengue fever effectively.

Days/Test	1	2	3	4	5	6	7	8	9
IgG 1st							+	+	+
IgG 2nd					+	+	+	+	+
IgM					+	+	+	+	+
NS1	+	+	+	+	+	+	+
Viraemia	+	+	+	+	+

Other lab test

1. Haemogram: Platelets are the most important parameter to watch as its levels go down to critical levels. TLC also goes down in fevrile phase.
2. LFT: LFT is also deranged in dengue.
3. KFT: It is also advisable to monitor the albumin level.
4. Other routine test.

Clinical course

The clinical course of dengue unfolds in distinct phases, each characterized by specific symptoms. Dengue typically begins with the sudden onset of fever, accompanied by several hallmark features, including headaches (often situated behind the eyes), muscle and joint pains, and the development of a rash. This collection of symptoms has earned dengue the colloquial name “breakbone fever.” The overall progression of the infection can be divided into three phases: the febrile phase, the critical phase, and the recovery phase.

1. Febrile Phase:

• During the febrile phase, individuals experience a high fever, which may escalate to temperatures exceeding 40°C (104°F).
• This phase is marked by generalized pain and intense headaches.
• It typically persists for a duration of two to seven days.
• Nausea and vomiting are common symptoms experienced during this period.
• Approximately 50-80% of those with dengue symptoms develop a rash. This rash may appear as flushed skin either on the first or second day of symptom onset or later, typically between days 4 to 7.
• Some individuals may exhibit petechiae, which are small red spots on the skin that do not disappear when pressed. These spots are caused by broken capillaries.
• Mild bleeding from the mucous membranes of the mouth and nose can also occur.
• The fever often follows a biphasic or saddleback pattern, with the temperature temporarily subsiding before returning for one or two days.

2. Critical Phase:

• The critical phase follows the resolution of the fever in some individuals.
• During this period, there is a leakage of plasma from the blood vessels, which typically lasts for one to two days.
• This plasma leakage can result in fluid accumulation in the chest and abdominal cavity. It may lead to the depletion of fluids from the circulation.
• It can also result in reduced blood supply to vital organs.
• Organ dysfunction and severe bleeding may occur, particularly from the gastrointestinal tract.
• Severe manifestations like shock (known as dengue shock syndrome) and extensive bleeding (referred to as dengue hemorrhagic fever) are relatively rare and are observed in less than 5% of all dengue cases.
• However, individuals with a history of prior infection with other dengue virus serotypes (“secondary infection”) are at a heightened risk.
• Notably, this critical phase is more common among children and young adults.

3. Recovery Phase:

• The recovery phase typically ensues after the critical phase.
• During this stage, the leaked fluid begins to resorb into the bloodstream, which usually spans two to three days.
• Improvement during this phase can be striking, accompanied by severe itching and a slower heart rate.
• Another rash may emerge, with either a maculopapular or vasculitic appearance, followed by skin peeling.
• Fluid overload may occur during this stage, potentially affecting the brain and causing symptoms like reduced consciousness or seizures.
• Fatigue may persist for weeks in adults.

It is crucial to monitor dengue patients closely during these phases, particularly during the critical phase, to identify any signs of severe dengue and provide appropriate medical care when necessary. Dengue management should always be supervised by healthcare professionals to ensure the best possible outcome.

Additional Complications

Dengue can, on occasion, lead to various complications affecting different bodily systems, either in isolation or alongside the classic dengue symptoms. These complications may include:

1. Altered Consciousness: In severe cases of dengue, a reduced level of consciousness may occur, affecting approximately 0.5% to 6% of patients. This alteration in consciousness can be attributed to the virus’s direct impact on brain inflammation or indirectly as a consequence of impaired vital organs, such as the liver.

2. Neurological Disorders: Dengue has been associated with other neurological disorders. Examples include transverse myelitis and Guillain–Barré syndrome, both of which have been reported in the context of dengue infection.

3. Cardiac Involvement: Although rare, infection of the heart can be a complication of dengue, potentially affecting heart function.

4. Acute Liver Failure: Another infrequent complication is acute liver failure, which can result from severe dengue infection.

5. Pregnancy-Related Risks: Pregnant women who contract dengue face an elevated risk of complications, including a higher likelihood of miscarriage, low birth weight in newborns, and premature birth.

These additional complications underscore the importance of timely medical evaluation and care when dealing with severe dengue cases. Monitoring and appropriate medical intervention are crucial to manage these complications and minimize their impact on the affected individuals.

Treatment

Treating Dengue Fever

Currently, there is no specific antiviral treatment for dengue fever. The management of dengue primarily revolves around supportive care, which includes:

Hydration:

• Hydration is a critical aspect of managing dengue fever. Dengue fever can cause a range of symptoms, including high fever, vomiting, diarrhea, and severe joint and muscle pain, all of which can lead to dehydration. Dehydration can exacerbate the symptoms and complications of dengue, so maintaining proper hydration is essential. Here’s what you need to know about hydration during dengue fever:
• Why Hydration Matters:
• Fever and Sweating: High fever is a hallmark symptom of dengue fever. Elevated body temperature can lead to increased sweating, causing fluid loss from the body.
• Vomiting and Diarrhea: Some dengue patients experience vomiting and diarrhea, which can further contribute to fluid loss and electrolyte imbalances.
• Dehydration: The combination of fever, sweating, vomiting, and diarrhea can quickly lead to dehydration, which can be dangerous, especially in severe cases of dengue.
• How to Stay Hydrated:
• Drink Plenty of Fluids: The most important step in managing dengue-related dehydration is to drink ample fluids. Water is the best choice, but you can also consider oral rehydration solutions (ORS) that contain electrolytes. ORS helps replenish lost fluids and electrolytes like potassium, sodium, and chloride.
• Frequent Small Sips: Encourage the patient to take frequent small sips of water or ORS throughout the day. Sipping slowly can help prevent nausea and vomiting.
• Coconut Water: Coconut water is a natural source of electrolytes and can be a good choice to stay hydrated.
• Clear Broths and Soups: Clear broths, such as chicken or vegetable broth, and clear soups can provide both fluids and some nourishment.
• Avoid Sugary and Caffeinated Beverages: Sugary drinks and caffeine can be dehydrating, so it’s best to avoid them during dengue fever.
• Avoid Alcohol: Alcohol can dehydrate the body, so it should be strictly avoided.

Signs of Dehydration:

• It’s important to monitor for signs of dehydration in individuals with dengue fever. If any of these signs are present, seek medical attention promptly:
• Dry or Sticky Mouth
• Dark Yellow Urine
• Infrequent Urination
• Sunken Eyes
• Dizziness or Lightheadedness
• Rapid Heartbeat
• Excessive Fatigue or Weakness
• Irritability or Confusion

Pain Relievers: Paracetamol (Dolo) 500/650 mg tds

Pain relief is an essential component of managing the symptoms of dengue fever. Dengue fever often causes severe joint and muscle pain, which can be very uncomfortable. However, it’s crucial to choose the right pain reliever because some medications can increase the risk of bleeding, which is a concern with dengue. Here are some recommendations for pain relief in dengue:

1. Acetaminophen (Paracetamol): Acetaminophen is generally considered the safest option for pain relief in dengue. It can help reduce fever and alleviate joint and muscle pain. It does not have the same bleeding risk as non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or aspirin. Follow the dosing instructions on the medication label or consult with a healthcare professional for the appropriate dosage.
2. Avoid NSAIDs: Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and aspirin, should be avoided during dengue fever. These medications can increase the risk of bleeding, which is a complication associated with severe dengue.
3. Consult a Healthcare Professional: It’s essential to consult a healthcare professional for guidance on pain relief if you have dengue fever, especially if your symptoms are severe. They can provide specific recommendations based on your condition and medical history.
4. Temperature Control: If you have a high fever, aside from pain relief, consider using tepid sponging or taking a lukewarm bath to help lower your body temperature gradually. Avoid cold water or ice baths, as they can cause shivering, which may worsen muscle pain.

Antiemetic: Ondenseteron 4 mg bd

Ondenseteron 4 mg can be given as per need to curb vomiting.

supportive drug:

Dengue fever supportive therapy

1. Calcium tablet
2. Multivitamin
3. Caripill: Papaya extract can be given, but its benefit is doubtful.

• Rest: Getting sufficient rest is essential for a full recovery, as it allows your body to fight off the infection effectively.
• Hospitalization for Severe Dengue

In cases of severe dengue, also known as dengue hemorrhagic fever or dengue shock syndrome, hospitalization is often necessary. Hospitalized patients receive more intensive care, including intravenous fluids to maintain hydration and close monitoring of vital signs. The prompt medical intervention in these cases is critical to preventing complications and fatalities.

Prevention

How to Prevent Dengue

Preventing dengue primarily entails reducing your risk of mosquito bites. Here are effective preventive measures you can take:

1. Use Mosquito Repellent: Apply mosquito repellent on exposed skin and clothing, particularly during peak mosquito activity times.
2. Wear Protective Clothing: Cover up by wearing long-sleeved shirts, long pants, socks, and closed shoes to minimize exposed skin.
3. Stay in Air-Conditioned or Screened-In Areas: Aedes mosquitoes often seek shelter indoors, so staying in well-screened or air-conditioned places can provide protection.
4. Remove Mosquito Breeding Sites: Eliminate stagnant water in and around your home, as these areas serve as breeding grounds for mosquitoes. Regularly empty containers that collect water and clean gutters.
5. Use Bed Nets: Sleeping under bed nets, especially if you don’t have access to air conditioning, can safeguard you from mosquito bites during the night.
6. Fogging is a method of insecticide application that involves the dispersion of a fine mist of insecticide into the air. The aim is to kill adult mosquitoes, particularly the Aedes mosquitoes responsible for transmitting the dengue virus. Fogging is typically conducted using specialized equipment, such as thermal foggers or ultra-low volume (ULV) foggers.

Benefits of Fogging for Dengue Prevention:

1. Rapid Reduction in Adult Mosquitoes: Fogging can quickly reduce the population of adult mosquitoes in a specific area. This can be particularly useful during dengue outbreaks when there is an urgent need to reduce the risk of transmission.
2. Targeted Approach: Fogging can be directed to specific areas where dengue cases are reported or where mosquito activity is high, allowing for a more targeted approach to mosquito control.
3. Immediate Impact: Unlike some other mosquito control methods, fogging can provide immediate relief from mosquito bites and reduce the risk of dengue transmission.

Community Efforts

Preventing dengue isn’t solely an individual’s responsibility. Communities and local governments also play pivotal roles in controlling the spread of the virus. This involves initiatives to reduce mosquito breeding sites in public areas, proper waste disposal, and educating the public about dengue prevention.

Dengue Vaccines

Are There Vaccines for Dengue?

As of the time of writing this guide, several dengue vaccines have been developed and are available in some countries. However, their availability and usage recommendations vary by region and are subject to change over time. Dengue vaccination decisions should be made in consultation with healthcare professionals and based on individual risk factors, such as geographic location and previous dengue exposure.

Conclusion

In conclusion, dengue fever is a viral illness transmitted primarily by mosquitoes in tropical and subtropical regions worldwide. While most cases of dengue are mild and can be managed at home with rest, fluids, and over-the-counter pain relievers, severe dengue can be life-threatening and requires immediate medical attention. Preventing dengue primarily involves minimizing mosquito exposure through protective measures such as mosquito repellent, appropriate clothing, and the elimination of breeding sites.

It’s essential to stay informed about dengue and take proactive steps to protect yourself and your community from this mosquito-borne illness. If you suspect you have dengue fever or experience severe symptoms, seek medical care promptly. By understanding dengue and adopting preventive actions, we can collectively reduce the impact of this disease on our lives and communities, ultimately working towards a dengue-free future.