A case of the flu can quickly take a turn for the worse. Knowing the warning signs and immediate treatment is vital.
Influenza can range from being a light illness to a serious disease, and when complicated by acute myocarditis, it could be life-threatening.
However, two recent cases of fulminant myocarditis in Taiwan caused by influenza have again made influenza complicated by myocarditis a topic of much attention.
One case involved a 55-year-old male patient who was diabetic and overweight. One week after recovering from the flu, he suddenly felt chest tightness and heart palpitations. He fainted at his workplace and was rushed to the emergency room for immediate treatment. He was later diagnosed with myocarditis.
Easily Overlooked or Misdiagnosed
Fulminant myocarditis has the following characteristics:
Easily Misdiagnosed. The initial symptoms may be similar to the flu, so it could be ignored, delayed, or misdiagnosed.
Rapid Onset. Symptoms worsen rapidly over a short period of time, possibly leading to death within hours or days.
Severe Symptoms. Severe heart failure and arrhythmias occur early on.
High Mortality Rate. If not treated promptly, the mortality rate is extremely high.
Causes of Myocarditis Caused by Colds
The common cold is an upper respiratory tract infection usually caused by a virus (more than 200 species are currently identified). The chance of myocarditis occurrence is quite rare.
Myocarditis is inflammation of the heart muscle layer, which affects the heart’s ability to pump blood, leading to irregular heartbeats. Most myocarditis cases are caused by infection, primarily viral, including influenza, COVID-19, herpes, coronavirus, and adenovirus, among others. There could be other causes, too, including medications, bacterial infections, and autoimmune diseases such as rheumatoid arthritis or systemic lupus erythematosus.
Be Wary of Early Symptoms
The initial symptoms of myocarditis may be similar to those of ordinary influenza, such as fever, cough, etc. However, warning signs, such as chest pain, difficulty breathing, palpitations, and irregular heartbeat, may appear later.
Zheng said that if those symptoms suddenly appear during or after the flu, especially if the chest pain lasts more than 15 minutes, you should seek medical treatment as soon as possible.
He said that in the early studies on fulminant myocarditis, most of the data were obtained from autopsies because it was often too late by the time the patients went to the hospital.
High Risk Groups
- People with chronic diseases, such as diabetes or high blood pressure, are more vulnerable to post-infectious complications.
- People with autoimmune diseases, such as lupus or rheumatism.
- People undergoing cancer treatment. Some drugs, such as chemotherapy drugs, can increase the risk of myocarditis.
- People infected with CID-19 or vaccinated with the mRNA vaccine. A review published in JAMA showed that the number of myocarditis/pericarditis cases related to COVID-19 has increased by at least 15 times compared to pre-pandemic, regardless of whether you have the virus or are vaccinated. This is especially the case for those who have received their second dose.
Studies show that COVID-19 itself is more likely to cause myocarditis in most people than the vaccine. A University of California-led study also found that COVID-19 infection is more likely to cause cardiovascular complications than respiratory viral infections such as influenza and respiratory syncytial virus.
Zheng said that although acute myocarditis is uncommon, once it occurs, it may be life-threatening. We are currently in a susceptible period for influenza and various viruses, and everyone should remain alert to certain acute complications and seek medical treatment as soon as possible whenever there are any signs of it.