Blood Infection (Sepsis)

Infection means an invasion of microorganisms in the body’s normal tissue. The invading microorganisms can be any type of bacteria, fungi, virus or parasite. If the infection spreads into the bloodstream with signs and symptoms, it is called blood infection. Sepsis is a hyper-response or unusual response of the body’s immune system to the spreading infection. Blood infection causes inflammation in the organs to which it spreads. The inflammatory response of the organs does not allow them to function properly. This leads to the development of signs and symptoms such as a low or high body temperature, an increase in heart rate and breathing rate, and increased white blood cell count. Earlier, blood infection was called septicemia, but now, it has been replaced by the word ‘sepsis’, which means infection with signs and symptoms. Sepsis is a preventable complication of a neglected infection. Awareness about sepsis is important as 20% of the hospitalized patients lose their lives due to sepsis. This mortality rate is approximately equal to the that of people dying due to a heart attack.

What is blood infection or sepsis?

Blood infection or sepsis is a complication of an infection in which the body's immune system has an unusual response to microorganisms and their toxins. These microorganisms may be bacteria, virus, fungi, or parasite, or their toxins that spread into the bloodstream. Blood infection can adversely affect every organ system leading to their dysfunction, which may be life-threatening.

Sepsis is related to many signs and symptoms which can make the diagnosis difficult.  However, three most important symptoms are considered diagnostic with or without confirmation of the presence of an infectious source. These symptoms are:

• A high or low body temperature
  There may be an increase or decrease in the body temperature due to sepsis. Temperature can rise above 38°C causing fever or may go below 36°C causing shivering.
• Increase in heart rate
  Normal heart rate is calculated by the number of times the heart beats in one minute. The normal heart rate ranges from 60-100 beats per minute. Greater than 100 beats per minute is considered as an increase in heart rate, which is also known as tachycardia in medical terms.
• Increase in breathing rate
  Breathing rate, also known as respiratory rate, is the number of breaths taken by a person in one minute. Normal breathing rate is 16-20 breaths per minute. In sepsis, the breathing rate increases to more than 20 breaths per minute.

Causes

Blood infection is caused by a hyper-response of the immune system to microorganisms that enter the body. This means any type of bacteria, virus, fungus, or parasite can cause sepsis, but the most common cause is infection by bacteria, which accounts for around 70 - 80 % of cases of a blood infection.

Blood infection can be due to severe infections of the lungs and abdomen, which can easily reach the bloodstream through circulation.

Risk Factors

There is an increased risk of spread of infection in:

• Intravenous drug users
  People who require intravenous drugs or those who are drug abusers and addicts, frequently get pricked which increases the chances of infection to directly enter the bloodstream.
• People who have had a splenectomy
  If a person has undergone surgical spleen removal due to a medical condition, he/she has an increased risk of developing a blood infection.
• People with low immunity
  As immunity plays an important role in fighting infections, people with low immunity, such as those with HIV infection (Human Immunodeficiency Virus), cancer, children (as they develop immunity late), and elderly people (as their immunity weakens with age) are at an increased risk of blood infection.
• Poor hygiene and sanitation
  Living in areas with poor sanitation and hygiene, eating food without washing hands, wearing dirty clothes can increase the risk of blood infection.

There are many ways by which you can reduce the risk of a serious infection. These include:

• Treating the wounds
  Any wound, small or big in size, should not be neglected. You should always take care of it and if required, visit your doctor for proper treatment.
• Treating infections
  Even a common cold or a cough that lasts for more than a week can lead to sepsis. Hence, every infection should be treated with the help of a doctor’s advice by taking proper antibiotics and self-care.
• Regular dental checkup
  Dental caries is most of the time neglected by people. This can lead to the development of infection and its spread into the bloodstream. Hence, regular dental check-ups and treatment can save you from the spread of infection.
• Infection prevention
  To prevent an infection, wash hands before having meals and after using the toilet. Keep your house clean by using a disinfectant, bathe regularly, use clean beddings and linen, and go for routine health check-ups at six months interval to prevent infection.
• Oral antiseptics for mouth care
  Oral hygiene is very important as infection can directly spread from the mouth to the stomach and from the stomach to the bloodstream. This type of infection can be prevented by daily brushing of teeth and gargles.
• Antibiotic prophylaxis
  If there is a high risk of infection, such as in people who are admitted in the hospital over a long period of time or in case of surgery, it is always better to start prophylactic antibiotics to prevent the risk of infection.

The first step to a successful treatment of blood infection is an early diagnosis. Diagnosis is established by assessing the person’s symptoms and signs, physical examination, and diagnostic laboratory tests. Following tests are performed to establish the correct  diagnosis:

• Physical examination findings such as an increase in the respiratory rate, a decrease in the blood pressure, a low or high body temperature, a decrease in the urine output may be present in a person with sepsis.
• Complete blood count showing abnormal white blood cell count and decreased platelet count suggests the presence of some sort of infection.
• Renal (kidney) or Liver function test showing a reduced albumin level (a type of protein) can also suggest an infection.
• Other tests like abnormal blood sugar levels (either increase or decrease), low calcium levels, increased lactic acid levels can also give some clue to the diagnosis.
• The source of the infection can be found by observing the person for new symptoms or signs related to any part of the body. This may indicate the presence of infection in that body part. The suspected source of infection can be confirmed by the use of radiological imaging techniques such as an X-ray, CT scan, or ultrasound among others.

Treatment should be started as soon as the person is hospitalised as the primary aim is to normalise the heart rate, breathing, and respiration of the person. Treatment includes:

• Fluids
  For initial stabilization before a diagnosis is established, fluids in the form of normal saline can be administered to the person by injecting it in veins in a controlled manner with the help of an intracatheter. This will allow the maintenance of normal blood pressure. The fluid load is monitored by observing the urine output, blood pressure, and lactate levels in the person’s body.
• Temperature control
  Raised temperature can be controlled by using physical methods of cooling like cold water sponging, cooling blankets along with the use of antipyretic drugs (medicines for fever) such as paracetamol.
• Antibiotics
  Initial antibiotic therapy is started by using antibiotics which can cover all the likely microbes that could have caused the infection. The antibiotics are continued until the exact diagnosis is established. As soon as the blood culture or the urine culture reports suggest the causative microorganism, prompt antibiotic therapy specific to the diagnosed microbe is started within one hour of diagnosis. Antibiotics can be continued until signs of complete recovery from the infection are seen.
• Source identification and control
  Detecting the source of blood infection means finding out the local infection which has spread in the bloodstream and is responsible for all the resulting signs and symptoms. It is very crucial to find the source of infection to avoid further spread of infection and to control the current infection. The earlier the source is found, and the antibiotic treatment started, the more are the chances of preventing further damage to other organs.
• Drugs to maintain blood pressure
  Some drugs can be used for maintaining blood pressure along with fluid therapy if fluids alone are not adequate. Whole blood transfusion can be performed in cases where the haemoglobin concentration of blood goes below 7gm/dL. (Read more - High blood pressure treatment)
• Stress ulcer prevention
  Stress ulcers that appear in the stomach due to the physiologic stress that the body is undergoing (due to chronic illness) should be prevented to avoid bleeding, which can lead to further decrease in the blood pressure. This can be done by prescribing drugs like H2 blockers prophylactically. (Read more - Stomach ulcers causes and treatment)
• Lung protective ventilation
  For the protection of the lungs, oxygen supply can be provided continuously and if needed, using machines called ventilators.
• Surgery
  An abscess is a pus-filled cavity which needs to be removed to cure the source of infection in sepsis. An abscess present anywhere on the body can be drained completely by a small cut, but if it is present inside the body, then surgical removal is required.

Lifestyle management

Lifestyle modifications can help to prevent infections, and thus, sepsis. These include:

• Healthy balanced diet
  A healthy diet that includes all necessary minerals, vitamins, a balanced proportion of carbohydrate (up to 60%), proteins (up to 30%), and fats (5 -10 %) helps to keep your immunity strong.
• Acquiring healthy habits
  Healthy habits such as washing hands before eating food or after using the toilet, wearing clean clothes, using clean linen, and keeping the house and surrounding environment clean can help prevent infections.

Prognosis

The outcome of blood infection and sepsis is very poor as it is difficult to detect the source of infection. Also, it progresses fast allowing less time to decide the correct line of treatment and involves progressive dysfunction of the organs.

Complications

Complications of sepsis are life-threatening, so early diagnosis and treatment are necessary to save the life of the person. Some important complications are:

• Severe sepsis
  Sepsis with one or more organ dysfunction is called severe sepsis. It is a serious condition in which the infection through the bloodstream reaches other vital organs and affects them. Due to the spread of sepsis, the organs stop functioning properly.
• Septic shock
  Due to sepsis, the blood pressure decreases, known as hypotension to such an extent that the patient can land into a series of complications causing shock. In hypotension, the systolic blood pressure drops below 90 mm of Hg and the diastolic blood pressure below 60 mm Hg when measured by a Sphygmomanometer (blood pressure measuring instrument). The septic shock induces more organs to stop working properly due to a reduced blood supply.