What does a low serum complement C3 level indicate?

Low serum complement C3 levels usually indicate reduced complement synthesis capacity and may be associated with conditions such as dermatomyositis, liver function decline, and myocardial infarction.

1. Dermatomyositis

Dermatomyositis is often caused by genetic factors or triggered by infections. Common symptoms include skin itching and pain. Localized inflammation can affect the body's complement levels, and in severe cases, lead to decreased complement C3. Treatment may involve oral medications such as azathioprine tablets or methotrexate tablets under medical supervision.

2. Liver Function Decline

Liver failure is typically caused by long-term heavy alcohol consumption or viral infections, which commonly result in reduced complement C3 levels. Treatment may include medications such as reduced glutathione tablets or polyene phosphatidylcholine capsules, taken under a doctor’s guidance.

3. Myocardial Infarction

Myocardial infarction is generally caused by underlying conditions such as hypertension or hyperlipidemia. Severe cases may present with chest pain and difficulty breathing. A decrease in complement C3 levels may also occur. Prompt treatment via coronary intervention is required under medical supervision.

In addition, patients with hepatitis may also exhibit low serum complement C3 levels. It is important to seek timely medical evaluation and receive appropriate treatment based on the underlying cause.