Myocardial Infarction and the Causes of Fever

It is not uncommon for patients to experience fever following a myocardial infarction. This phenomenon can be attributed to several underlying factors that are closely related to the physiological changes occurring in the body after heart tissue damage.

1. Absorption of Necrotic Tissue

One of the primary causes of fever after a heart attack is the release of necrotic (dead) tissue into the bloodstream. When heart muscle cells die due to lack of oxygen, the body begins to break down and absorb these damaged cells. This process can lead to what is known as an "absorption fever." Typically, this type of fever is mild, rarely exceeding 38°C (100.4°F), and usually appears within the first few days after the myocardial infarction.

2. Reduced Cardiac Function Leading to Pulmonary Congestion

Another contributing factor is the decline in cardiac function that often follows a heart attack. When the heart's ability to pump blood efficiently is compromised, it can lead to increased pressure in the pulmonary veins, causing fluid to accumulate in the lungs—a condition known as pulmonary congestion. This fluid buildup can make breathing difficult and may worsen if the patient remains physically active. For this reason, doctors often recommend bed rest to reduce the workload on the heart and minimize further complications.

3. Complications from Prolonged Immobility

Extended bed rest, while necessary for recovery, can also bring about its own set of risks. One such risk is the pooling of fluids in the lungs, which can create an environment conducive to bacterial growth and lead to lung infections such as pneumonia. These infections can cause a secondary fever, typically appearing on the second day after the heart attack or later.

The Importance of Timely Antibiotic Treatment

If a lung infection is left untreated, it can significantly increase the burden on the already weakened heart. This added stress may delay recovery, impair the healing of damaged heart tissue, and potentially worsen the overall prognosis of the myocardial infarction. Therefore, prompt diagnosis and appropriate antibiotic therapy are crucial in managing post-heart attack fever, especially when infection is suspected.