Bacteremia

Introduction Bacteremia refers to the fact that bacteria outside the body enter the blood system through the entrance of the body surface or the entrance to the bloodstream, and then propagate in the blood of the human body and spread with the bloodstream. The consequences are very serious. In general, a urinary catheter or a surgical stoma on the surface of the body is prone to bacteremia. Patients with bacteremia often develop acute metastatic infections of multiple organs, and if symptoms of various acute infections are suspected, blood tests should be taken immediately. Once diagnosed, the treatment of infected bacteria should be immediately scored. Most of the bacteremia is that the bacteria enter the blood from the local lesions, and there is no symptoms of poisoning in the whole body, but bacteria can be found in the blood. It mainly occurs in the early stages of inflammation, and macrophages of the liver, spleen and bone marrow can form a line of defense to remove bacteria.

Cause

Invasive oral tissue surgery or routine dental procedures, infection of the lower urinary catheter, abscess incision and drainage and built-in bacterial growth, especially intravenous and intracardiac catheters, catheters and ostomy built-in Both the device and the catheter can cause transient bacteremia. Typical Gram-negative bacteremia is intermittent and opportunistic, although this bacteremia may not affect healthy people, but patients with impaired immune disease and severe disease, post-chemotherapy patients, and severe malnutrition , can have serious consequences. The initial site of infection is usually in the lungs, genitourinary tract, gastrointestinal tract or soft tissue, including skin with acne ulcers. It can also occur in dangerous people, especially after dental surgery in patients with valvular heart disease, prosthetic heart valves or other endovascular prostheses.

an examination

Related inspection

Blood routine intravenous pyelography

Symptoms and signs:

Typical transient and low levels of bacteremia are asymptomatic unless the patient is at risk of persistent or high levels of bacteremia. Typical manifestations are signs of systemic infection, including shortness of breath, chills, rising body temperature and gastrointestinal symptoms (abdominal pain, nausea, vomiting, diarrhea). In the early stages of the disease, the patient's skin tends to be warm and alert. If blood pressure is not measured, hypotension will not be found, and some patients will have lower hypotension.

Some features help identify the cause and pathogenic bacteria. Most of the infections above the diaphragm are caused by Gram-positive bacteria, and abdominal infections, including biliary and urinary tract infections, are mostly caused by Gram-negative bacteria. However, in addition to the experimental diagnosis of Gram-positive bacteria and Gram-negative bacteria bacteremia and septic shock, there is no other reliable identification method.

Metastatic abscesses can occur in almost any part, and can also produce characteristic signs and symptoms of affected organ infections in a wide range. In the case of staphylococcal bacteremia, multiple abscess formation is common. In 25% to 40% of patients with persistent bacteremia, hemodynamic instability can occur and septic shock occurs.

Differential diagnosis

Differential diagnosis:

1, sepsis: bacteria invade the blood and rapidly grow and multiply, causing systemic infection symptoms. The onset of the disease is that it begins a severe chill, and continues to have a high fever of 40 to 41 °C, accompanied by sweating, headache, and nausea.

2, toxemia: bacterial toxins from the local infection of the lesion into the blood circulation, resulting in systemic sustained high fever, accompanied by a lot of sweating, pulse weak or shock. Anemia is often caused by bacterial toxins in the blood that directly destroy blood cells in the blood. Bacteria can not be found in blood culture. It is worthy of special attention to serious injuries, vascular embolism, intestinal obstruction and other diseases. Although there is no bacterial infection, the toxins produced by large-area tissue destruction can also cause toxemia.

3, sepsis: the bacteria in the body of purulent lesions, through the blood circulation "touring the country", spread to other parts to produce new suppurative lesions, caused by systemic infection symptoms. The characteristics of the disease are similar to those of sepsis, but many suppurative lesions can be found on the body, and there are even many abscesses.

diagnosis:

Pus or body fluids should be obtained from all infected sites, including infected body cavities, joint spaces, soft tissues, and diseased skin for Gram staining and culture. Blood culture should include aerobic and anaerobic cultures. Blood culture should be performed twice a day at intervals of one hour. Blood should be taken from different sites at each time. Two blood cultures are sufficient for the initial diagnosis of bacteremia, but negative staining or culture results cannot exclude bacteremia, especially in patients who have previously received antibiotics, and cannot exclude bacteremia. This specimen of at least 2 blood cultures should be taken from a properly prepared venous incision site. In addition, specimens of sputum, catheter insertion sites and wounds can be cultured.

Two or more of the following objective indicators can be considered as the previously known septic syndrome: the current systemic inflammatory response syndrome: body temperature > 38 ° C or < 36 ° C; heart rate > 90 beats / min; breathing Rate >20 times/min or arterial carbon dioxide partial pressure (paCO2) <32mmHg; white blood cell count >12000/l or <4000/l, or immature white blood cells >10%, typical white blood cell count is initially reduced to <4000/l Then, it rose to >15000/l in 2-6 hours, and the immature type increased significantly.

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