Flu-like symptoms

Introduction Many drugs used to treat the flu, such as the antiviral drugs ribavirin, ganciclovir, etc., can also cause flu-like symptoms, called "drug-like influenza-like syndrome (DFS)." It is well known that influenza is a relatively serious respiratory infection caused by influenza viruses. However, in recent years, many drugs have been found to have some flu-like adverse reactions during use. As early as 1967, some scholars discovered that this situation can occur when interferon (IFN) is applied, and it will be reported more and more in the literature. Clinically, a group of symptom groups mainly caused by chills, fever, headache, limb muscle soreness and the like, with or without systemic discomfort, nasal congestion, salivation, rash, etc. Sexual influenza-like syndrome." However, the probability of a drug causing "flu" is still very low, and it is non-infectious. Once the drug is stopped, the flu-like symptoms will slowly disappear. Because this particular drug adverse reaction is easily confused with the flu, it is often missed or misdiagnosed as a general virus or flu and abused antiviral drugs. In recent years, with the emergence of new diseases caused by new virus or virus mutations, how to timely identify DFS and various types of influenza has received everyone's attention.

Cause

The symptoms of DFS are mostly non-specific flu-like symptoms:

1 chills fever, body temperature 37.5 ° C ~ 38.5 ° C, but generally does not exceed 39 ° C (except interferon and amphotericin B).

2 headache, dizziness or bloating, general malaise, fatigue and weakness.

3 limb muscles or joint pain.

4 nasal congestion, runny nose, sore throat, flushing, no flushing cause, intermittent episodes after 0.5 to 2 hours of medication, lasting 3 to 6 hours.

5 All symptoms disappeared or decreased rapidly after stopping the drug.

6 visible peripheral blood eosinophils increased.

7 anti-infective treatment is invalid.

The exact mechanism of its occurrence is still unclear. It is currently believed to be mainly related to type III allergic reactions. People with levamisole, penicillin, heparin, etc. may also have type II allergic reactions. In addition, there is direct toxicity of the drug or its own pathogenicity, stimulation of the body temperature center, dilation of vascular cholinergic toxicity and adverse effects of impurities in the preparation.

an examination

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Because clinically, the drug-induced influenza-like syndrome has not received enough attention, most patients are not easy to diagnose in time, and those with mild manifestations are often overlooked. Many of the typical symptoms are also misdiagnosed. The diagnostic DFS standard is not yet unified, mainly based on several points:

1 history of medication (usually within 1 to 2 weeks after taking the drug).

2 There is flu-like clinical manifestation, and some patients have elevated blood eosinophils (other experimental indicators have no features to follow).

3 The symptoms disappeared or decreased rapidly after stopping the drug. If necessary, conduct a drug challenge test (refer to the general drug adverse reaction standard). If it is positive, it can help the diagnosis (this method should be implemented cautiously to avoid accidents).

Differential diagnosis

Differential diagnosis of flu-like symptoms:

1. Influenza (ingluenza): referred to as influenza, is an acute respiratory infection caused by influenza virus. The clinical features are acute high fever, body aches, fatigue, or mild respiratory symptoms. The disease has a short incubation period, is highly contagious, and spreads rapidly. The flu virus is divided into three types: A, B, and C. The flu is the most threatening. Because the influenza virus is highly pathogenic and prone to variability, if the population lacks immunity to the mutant strain, it is easy to cause an outbreak. So far, there have been five major epidemics and several minor epidemics in the world, causing billions of people to become ill. The death of thousands of people has seriously affected people's social life and production.

2. Transient flu-like symptoms: Avian influenza is a syndrome of poultry and wild birds caused by influenza A virus, ranging from respiratory diseases to severe sepsis. It has occurred in many countries and regions in the world, causing huge economic losses to the poultry industry. This avian influenza virus mainly causes systemic or respiratory diseases of poultry. Poultry and wild birds such as chickens, turkeys, ducks and quails, water birds and seabirds can be infected, mainly depending on the resistance of the diseased body. The type and virulence of the virus.

The avian flu virus is different from the SARS virus. The avian flu virus has so far only been transmitted to humans through poultry and cannot be transmitted to humans through humans. The human avian influenza virus H5N1 is a new variant of the virus, not the H5N2 that has been circulating in chickens and ducks for decades. There is no need to talk about the avian flu discoloration. At present, no chickens have been found to cause bird flu H5N1 infection. They are all in close contact with chickens, which may cause infections due to direct inhalation or entry into the mucosa.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.