What is sepsis?
Who is at risk?
Is the occurrence of sepsis increasing over time?
Are there many forms of sepsis?
How does sepsis show itself?
What are the most common sources of sepsis?
Related links

WHAT IS SEPSIS?

Sepsis can be defined as the body's response to an infection. An infection is caused by microorganisms or "germs" (usually bacteria) invading the body and can be limited to a particular body region (e.g., a tooth abscess) or can be widespread in the bloodstream (often called "septicemia" or "blood poisoning"). 

Although everybody is at potential risk of developing sepsis from minor infections (e.g., flu, urinary tract infections, gastroenteritis, etc.), sepsis is most likely to develop in people who:

• Are very young (e.g., premature babies) or very old
• Have a weakened ("compromised") immune system, often because of treatments such as chemotherapy for cancer, steroids (e.g., cortisone) for inflammatory conditions, etc.
• Have wounds or injuries, such as those from burns, a car crash, or a bullet
• Have certain addictive habits, such as alcohol or drugs
• Are receiving certain treatments or examinations (e.g., intravenous catheters [a small tube for dripping fluids into the vein], wound drainage, urinary catheters [a small tube inserted into the bladder]
• Are more prone to develop sepsis than others because of genetic factors (or their "genes")

Patients who are admitted to the hospital with serious diseases are at the highest risk
of developing sepsis because of:

• Their underlying disease
• Their previous use of antibiotics
• The presence of drug-resistant bacteria in the hospital
• The fact that they often require an intravenous tube, urinary catheter, or wound drainage

The infection leading to sepsis can be acquired outside the hospital (known as "community-acquired") or in the hospital (known as "nosocomial"). Hospital-acquired infections are generally more difficult to manage than those acquired in the community, because:

• The infecting microorganism is more dangerous to the patient
• The patient is often already sick
• The microorganism may be resistant to common treatments due to the widespread use of antibiotics in hospitals

Yes, sepsis is becoming more common, especially in the hospital, as a result of:

• Medical and technological advances associated with treatments
• The increasing number of elderly or debilitated people and patients with underlying diseases such as cancer, who require therapy
• The widespread use of antibiotics, which encourages the growth of drug-resistant microorganisms

Sepsis occurs in three different forms or stages, called:

• Uncomplicated sepsis
• Severe sepsis
• Septic shock

The disease progresses in some people through all three stages. Despite optimal (best or most favorable) care, some patients may not respond to treatment and may develop multiple organ disease and eventually die.

Uncomplicated sepsis

Uncomplicated sepsis, such as that caused by flu and other viral infections, gastroenteritis, or dental abscesses, is very common and is experienced by millions of people each year. The majority of these people will not need hospital treatment.

Severe sepsis

We estimate that more than 750,000 individuals develop severe sepsis in North America each year, with similar estimates for Europe, and all need to be actively treated in the hospital. Severe sepsis arises when sepsis occurs in combination with problems in one or more of the vital organs, such as the heart, kidneys, lungs, or liver.

Because of problems with their vital organs, people with severe sepsis are likely to be very ill and are more likely to die (in 30-35% of cases) than those with uncomplicated sepsis.

Septic shock

Septic shock occurs when sepsis is complicated by low blood pressure that does not respond to standard treatment (fluid administration) and leads to problems in one or more of the vital organs as described above. The condition means that the body does not receive enough oxygen to properly function and drugs called vasopressors are used to raise the blood pressure. Septic shock patients are very ill and need rapid emergency admission to the hospital intensive care unit ("ICU"). Despite active treatment in the ICU, the death rate is around 50%.

All three forms of sepsis can be identified by general signs, symptoms, and biological alterations, including those specific to the source of infection.

General signs and symptoms in sepsis

Sepsis patients generally have the following symptoms:

• Fever (i.e., high body temperature), often associated with shaking chills, especially in the early phase. However, in some cases, there is no fever, and patients may even have an abnormally low body temperature ("hypothermia"), especially if they are young or old
• Difficulty with breathing ("hyperventilation" or rapid breathing), that may result in shortness of breath
• Warm skin, sometimes associated with a skin rash
• Rapid heart beat ("tachycardia")
• General weakness

Infection site-specific signs and symptoms of sepsis

Some of the symptoms of sepsis also depend on the source of the infection, as shown by the following examples:

• With lung infection, there may be a shortness of breath and/or pus-like (known as "purulent") sputum ("phlegm" )
• With urinary tract infection, the patient may have painful urination and/or smelly urine
• With a central nervous system infection like meningitis, the patient may have a severe headache, reduced tolerance to light, and a stiff neck
• With abdominal infections, e.g., appendicitis, patients may have abdominal pain

Biological alterations in sepsis

Sepsis leads to alterations in the normal biological state of our bodies, such as:

• Altered white blood cell count – usually the number of white blood cells is increased in sepsis, reflecting the infection-fighting properties of these blood cells. However, in some severe cases, the white blood cell count may actually be abnormally low
• Bacteria or other microorganisms identified in biological fluids, such as blood, urine, phlegm, using laboratory tests

Signs of organic dysfunction in severe sepsis and septic shock

In severe sepsis and septic shock, the performance of any vital organ may be reduced, regardless of the source of infection.

The respiratory system

Sepsis patients often have serious respiratory problems (breathing difficulties) and these can sometimes lead to lung injury. Many patients require oxygen therapy, some may require insertion of a tube into their airway ("tracheostomy" or an "endotracheal tube"), and some may even need help by breathing machines ("mechanical ventilation").

The kidney

Alterations in kidney function can occur and are often associated with a decrease in urine output. In very severe cases, the kidney may sometimes temporarily fail entirely, and the patient’s blood will require repeated dialysis and/or continuous filtration using machines (i.e., use of an "artificial kidney").

The blood flow and blood clotting ("coagulation") system

Abnormalities in the blood clotting system are common and may affect the organs.

The central nervous system

The patient may be disoriented, confused, or have decreased alertness.

Liver function

• Alterations in the liver can occur and may result in jaundice (a yellow discoloring of the skin).
• Alterations in blood sugar ("hyperglycemia," "hypoglycemia").
• Alterations in sugar concentrations in the blood may require insulin administration even in non-diabetic patients.

People with problems in more than one of their organs are said to have "multiple organ dysfunction or failure."  

Sepsis can be caused by an infection in virtually any part of the body, although the following regions are most common:

The lungs

The lungs are the major source of infection in severe sepsis (especially with hospital-acquired infections), with sepsis usually associated with pneumonia.

The abdomen ("gut" or bowel)

There are numerous possible sources of infection in the abdomen, e.g., appendicitis, bowel problems, gallbladder infections. When the outer surface of the abdominal organs (called the peritoneum) is involved in the infection, it is called "peritonitis."

The urinary tract (kidney or bladder)

The urinary tract is another common source of infection, particularly in patients needing a urinary catheter. Diabetic patients are also at increased risk of urinary infections leading to sepsis.

The skin

Bacteria enter the skin through wounds and skin inflammations; they also enter the skin and blood through an opening provided by intravenous ("IV") catheters (small tubes for dripping fluids), which are required for the administration of fluids and/or medicines.

The bones

Sepsis can be associated with inflammation and infections of the bone, the bone marrow, the sinuses, etc.

The central nervous system

Sepsis can be associated with inflammation and infections in the brain (e.g., meningitis or encephalitis) or spinal cord.

In some cases (around 20%), the source of the sepsis can never be found.

These materials are furnished courtesy of the International Sepsis Forum.