World Heart Day: What people should know about dengue

This article is authored by Dr Mangesh Tiwaskar, consultant physician & diabetologist, Shilpa Medical Research Centre, Mumbai.

The daily life of a person with a heart condition centres around self-monitoring, strict medication schedules, and heart-healthy habits to manage and protect cardiovascular function. Blood pressure monitoring, physical activity, diet and regular check-ups often become part of a routine designed to keep the condition stable. But an acute infection can suddenly disrupt this balance and place additional strain on the heart.

Heart (Pixabay)

Dengue is one such infection that deserves the attention of heart patients, particularly during periods when mosquito-borne infections are on the rise.

To understand why dengue can be particularly concerning for someone with heart disease, it helps to understand what the infection can do to the heart and blood circulation.

One of the key changes that can occur in dengue is increased permeability of the blood vessels. In simple terms, the blood vessels can become leakier, allowing the fluid component of blood called plasma to move into the surrounding tissues. If this leakage becomes severe, the amount of fluid circulating through the bloodstream can fall. This can cause blood pressure to drop and reduce the amount of blood returning to the heart. In severe dengue, extensive plasma leakage can result in shock, where the body’s vital organs do not receive enough blood and oxygen.

Dengue can also affect the heart itself. Some patients may develop inflammation of the heart muscle, known as myocarditis, which can affect the heart’s ability to pump effectively. Changes in heart rhythm and other forms of cardiac involvement have also been reported with dengue. At the same time, fever and the body’s inflammatory response to infection can place additional demands on the cardiovascular system.

Thus, in people who already have cardiovascular disease, these effects can place additional stress on an already vulnerable heart and, in severe cases, may precipitate cardiac decompensation or acute heart failure.

Many heart patients take blood thinners or antiplatelet that keep the blood from clotting too easily. Dengue commonly lowers the platelet count, and these medicines can add to the risk of bleeding. This does not mean they should be stopped on one’s own; stopping them abruptly can itself be dangerous for the heart. Instead, a person with a heart condition who develops fever during dengue season should see a doctor early, mention every medicine they take, and allow the treating team to decide whether any dose needs to be adjusted temporarily while platelet counts are monitored.

Painkillers deserve special mention. Non-steroidal anti-inflammatory drugs (NSAIDs), a common class of painkillers, can worsen bleeding Some common anti-inflammatory painkillers can worsen bleeding. Your doctor will be able to guide you on which painkillers to take if you have dengue.

Blood pressure medicines and diuretics (water tablets) may also need review. During the phase of plasma leakage, and when fluid intake is poor because of vomiting or loss of appetite, these medicines can cause the blood pressure to fall too far and put strain on the kidneys.

Fluids are a double-edged sword for people with weak hearts. Plasma leakage calls for fluid replacement, but in the recovery phase the leaked fluid returns to the bloodstream, and a heart that cannot pump efficiently may struggle to cope, leading to breathlessness or fluid accumulation in the lungs. This balance is difficult to judge at home, which is why dengue in a person with heart failure or significant heart disease is best managed under close medical supervision rather than treated as an ordinary viral fever.

The message is simple: Do not stop, start or adjust any heart medicine on your own, but do tell your doctor about every medicine you take at the very first visit.

A point that is often misunderstood is that the most dangerous phase of dengue frequently begins as the fever settles, typically between the third and seventh day of illness. Patients feel better and relax their guard precisely when plasma leakage is most likely to occur. Anyone with dengue, and particularly those with heart condition, should watch for the following warning signs and seek medical care without delay:

• Persistent vomiting or severe abdominal pain
• Bleeding from the gums or nose, blood in vomit or stool, or unusual bruising
• Breathlessness or rapid breathing
• Unusual drowsiness, restlessness or confusion
• Cold, clammy hands and feet
• A marked fall in the amount of urine passed

For people with heart disease, there is an additional caution. Fatigue, breathlessness and palpitations occur both in dengue and when the heart is struggling, and it is easy to attribute a new cardiac symptom to just the fever. New or worsening breathlessness, chest discomfort, palpitations, or swelling of the feet during dengue or in the weeks after recovery should be reported promptly and not dismissed.

Many people with heart disease also live with diabetes or high blood pressure, both of which have been linked with a higher risk of severe dengue. In addition, blood sugar levels often become erratic during any febrile illness, so people with diabetes should check their glucose more frequently and stay in touch with their doctor while unwell.

While dengue can affect anyone, a recent systematic review and meta-analysis reported that pre-existing cardiovascular disease was associated with approximately 2.7-fold higher odds of severe dengue. With no specific antiviral treatment available to cure dengue and care being largely focused on supportive management, prevention becomes critical especially for people already living with cardiovascular disease. Dengue prevention works best when several measures are used together. Aedes mosquitoes primarily bite during the daytime, with peaks in the early morning and in the late afternoon before dusk, so personal protection should remain part of everyday prevention. Using mosquito repellents, wearing clothing that covers the arms and legs, and using screens on doors and windows where possible can help reduce exposure to mosquito bites.

Preventing mosquitoes from breeding around homes and communities is equally important. Water that collects in containers and other objects should be emptied regularly, water-storage containers should be properly covered, and waste that can collect rainwater should be disposed of appropriately. Community-level vector control, environmental management and surveillance remain fundamental because dengue prevention cannot depend on individual action alone.

At the same time, no single measure can prevent every dengue infection. Effective prevention requires an integrated approach combining mosquito control, environmental management, community participation, surveillance, early diagnosis and access to appropriate clinical care. Vaccination, where recommended by national health authorities and used according to approved indications, may complement these measures as part of an integrated dengue-control strategy.

World Heart Day is an important reminder that protecting the heart goes beyond managing cholesterol, blood pressure or lifestyle risks. For people already living with cardiovascular disease, preventing and promptly addressing infections that can place additional stress on the heart is also an important part of protecting their health. Dengue may begin with fever and body aches, but in people with underlying cardiovascular conditions, its effects can be more complex, making awareness, timely medical care and prevention particularly important.

(The views expressed are personal)

This article is authored by Dr Mangesh Tiwaskar, consultant physician & diabetologist, Shilpa Medical Research Centre, Mumbai.