Sepsis is a life-threatening
illness caused by the body overreacting to an infection. The body’s immune
system goes into overdrive, setting off a series of reactions that can lead to
widespread inflammation (swelling) and blood clotting.
Schematic diagram showing sepsis (infection in the bloodstream).
Symptoms usually develop quickly
and include:
- a fever or high temperature over 38C (100.4F)
- chills
- a fast heartbeat
- fast breathing.
In severe cases you may notice:
- you feel dizzy when you stand up
- confusion or disorientation
- nausea and vomiting.
Although anybody can develop
sepsis from a minor infection, some people are more vulnerable, such as those:
- with a medical condition or receiving medical treatment that weakens their immune system
- who are already in hospital with a serious illness
- who are very young or very old
- who have just had surgery or who have wounds or injuries as a result of an accident.
Schematic diagram showing how blood can become infected, leading to sepsis.
Sepsis develops in three
stages, described below.
- Uncomplicated sepsis is caused by infections, such as flu or dental abscesses. It is very common and does not usually require hospital treatment.
- Severe sepsis occurs when the body’s response to infection has started to interfere with the function of vital organs, such as the heart, kidneys, lungs or liver.
- Septic shock occurs in severe cases of sepsis, when your blood pressure drops to a dangerously low level, preventing your vital organs from receiving enough oxygenated blood.
If it is not treated, sepsis can
progress from uncomplicated sepsis to septic shock and can eventually lead to
multiple organ failure and death. If you think you have sepsis, it
is important to get it diagnosed and treated as quickly as possible. If
you think that you or someone in your care has severe sepsis or septic shock,
phone 999 and ask for an ambulance.
If sepsis is detected
early and has not yet affected vital organs, it may be possible to treat
the infection at home with antibiotics. Most people with uncomplicated
sepsis make a full recovery. Severe sepsis and septic shock are considered
medical emergencies and normally require admission to an intensive
care unit, where the body’s organs can be
supported while the infection is treated. Because of problems with vital
organs, people with severe sepsis are likely to be very ill, and approximately
30-50% will die as a result of the condition.
It is estimated that there are
over 30,000 cases of severe sepsis in the UK every year, and the number seems
to be rising.
Causes of Sepsis
Sepsis can be triggered by an
infection in any part of the body. The most common sites of infection
leading to sepsis are the lungs, urinary tract, abdomen and pelvis.
Types of infection associated
with sepsis include:
- lung infection (pneumonia)
- flu (influenza)
- appendicitis
- infection of the lining of the digestive system (peritonitis)
- an infection of the bladder, urethra or kidneys (urinary tract infection)
- skin infections, such as cellulitis, often caused when an intravenous drip or catheter has been inserted into the body through the skin
- post-surgical (after surgery) infections
- infections of the nervous system, such as meningitis or encephalitis.
In approximately one in five
cases, the infection and source of sepsis cannot be detected.
Usually, your immune system will
keep the infection limited to one place (known as a localised infection). Your
body will produce white blood cells, which travel to the site of the infection
to destroy the germs causing infection. A series of biological processes occur,
such as tissue swelling, which helps fight the infection and prevents it
spreading. This process is known as inflammation.
If your immune system is
weakened or an infection is particularly severe, it can spread through the
blood into other parts of the body. This causes the immune system to go into
overdrive, and the process of inflammation affects the entire body. This can cause more problems
than the initial infection, as widespread inflammation damages tissue and
interferes with the flow of blood, leading to a dangerous drop in blood
pressure, which stops oxygen reaching your organs and tissue.
Schematic diagram showing bacteria in the bloodstream, resulting in sepsis.
Everybody is potentially at risk
of developing sepsis from minor infections, such as flu. However, some people
are more vulnerable, including people who:
- have a medical condition, such as HIV or leukaemia, that weakens their immune system
- are receiving medical treatment, such as chemotherapy, that weakens their immune system
- are very young or very old
- have just had surgery, or have wounds or injuries as a result of an accident
- are on mechanical ventilation
- with drips or catheters attached to their skin
- are genetically prone to infection.
Sepsis is a particular risk for
people already in hospital due to another serious illness. Despite the
best efforts of doctors and nurses, secondary infections acquired in hospital
are always a potential risk. Hospital-acquired bacterial infections, such
as MRSA, tend to be more serious as the bacteria causing the infection
have often developed a resistance to antibiotics.
Symptoms of Sepsis
The symptoms of sepsis may
develop after a localised infection (infection limited to one part of the body)
or an injury. In some cases, sepsis may develop when you are already in
hospital, for example if you have recently had surgery and a drip or catheter
has been connected to your body.
The symptoms of sepsis usually
develop quickly and include:
- a fever or high temperature over 38C (100.4F)
- chills
- a fast heartbeat
- fast breathing
- confusion or delirium
Symptoms of severe sepsis or
septic shock include:
- low blood pressure that makes you feel dizzy when you stand up
- a change in your mental state, such as confusion or disorientation
- diarrhoea
- nausea and vomiting
- cold, clammy and pale skin.
The most common sites of
infection leading to sepsis are the lungs, urinary tract, abdomen and
pelvis. Severe sepsis and septic shock are medical emergencies. If you
think that you or someone in your care has these conditions, phone 999 and ask
for an ambulance.
Diagnosis of Sepsis
Sepsis is most often diagnosed
by a blood test. Other tests may help determine the type of infection, where it
is located and which body functions have been affected. To diagnose sepsis, several
tests may be carried out, including:
- blood tests
- urine tests
- stool sample tests
- blood pressure tests
- a wound culture test (where a small sample of tissue, skin or fluid is taken from the affected area for testing)
- respiratory secretion testing (which involves testing a sample of your saliva, phlegm or mucus)
- imaging studies such as an X-ray or computerised tomography (CT) scan
- kidney, liver and heart function tests
- a lumbar puncture (spinal tap) where a sample of cerebrospinal fluid is extracted from your back for testing.
In the case of suspected sepsis,
it is important to get a diagnosis as soon as possible so that appropriate
treatment can be given. This can help stop the progress of sepsis and any
long-term damage to the body.
Treatment of Sepsis
Treatment of severe sepsis will
vary for each patient depending on the initial infection, the organs affected
and the extent of damage. If your sepsis is detected early
enough and has not affected organ or tissue function (uncomplicated sepsis), it
may be possible to treat the condition at home. You will be prescribed a course
of antibiotic tablets.
If the sepsis is severe, or you
develop septic shock, you will need emergency hospital treatment, usually
in an intensive care unit (ICU). ICUs are able to support any
affected body function, such as breathing or blood circulation, while the
medical staff focus on treating the infection.
Severe sepsis is treated with
intravenous antibiotics (given directly into a vein). There will not
usually be time to wait until a specific type of infection has been identified,
so 'broad-spectrum' antibiotics will initially be given. Broad-spectrum
antibiotics are designed to work against a wide range of known infectious
bacteria, and can also treat some fungal infections.
Once a specific bacterium has
been identified, a more 'focused' antibiotic can be used. This has the
advantage of reducing the chance of the bacteria becoming resistant to
antibiotics. Intravenous antibiotics usually
have to be given for 7 to 10 days.
If the sepsis is caused by a
virus, antibiotics will not work. However, it is likely that antibiotics will
be started anyway. This is because it would be too dangerous to delay
antibiotic treatment until an accurate diagnosis is made. You will then need to
wait until your body develops resistance to the effects of the virus. In some
cases, antiviral medication may be given.
Schematic diagram showing how sepsis can cause Acute Renal Injury.
Source control means treating
the source of the infection, such as an abscess or infected wound.
This may require draining pus from infected tissue. In more serious cases,
surgery may be required to remove the infected tissue and repair any damage.
Vasopressors are medicines used
to treat low blood pressure. The two types of vasopressors used in the
treatment of sepsis are dobutamine and noradrenaline. They can help to
increase blood pressure by stimulating the muscles involved in pumping blood
around the body and constricting (narrowing) the blood vessels. Vasopressors are normally given
intravenously. Extra fluids may also be given intravenously to help increase
blood pressure.
Other treatments
Depending on your condition and
the effect sepsis has had on your body, you may also require:
- medication, such as steroids or insulin
- a blood transfusion
- mechanical ventilation to help you breathe
- dialysis (a machine to filter your blood) to help with kidney function.
Source: NHS Choices.
