Systemic Infection

A systemic infection is a serious medical condition where an infection spreads throughout the entire body, affecting multiple organs and tissues rather than remaining in one area. When infections reach the bloodstream, they can trigger life-threatening complications that require immediate medical attention.

Table of contents

• What is a Systemic Infection?
• Sepsis: The Body’s Dangerous Response
• Signs and Symptoms
• Causes and Risk Factors
• How Systemic Infections Are Diagnosed
• Treatment
• Prevention
• Recovery and Long-term Effects

What is a Systemic Infection?

A systemic infection means that an infection affects the entire body rather than just a single organ or body part^[1]. This is different from a localized infection, which stays in one specific area, like a skin wound or ear infection^[2].

When an infection is in the bloodstream, it is called a systemic infection^[2]. This happens when germs like bacteria, viruses, fungi, or parasites enter the blood and spread from the initial site of infection to other parts of the body^[5]. The infection can then affect multiple organs and tissues throughout the body^[4].

Systemic infections are serious medical emergencies that require prompt treatment. They can lead to dangerous complications, including organ failure and death if not treated quickly^[1].

Sepsis: The Body’s Dangerous Response

Sepsis is the most serious complication of a systemic infection. It occurs when your immune system has a dangerous reaction to an infection^[1]. Sepsis is defined as a life-threatening medical emergency caused by your body’s overwhelming response to an infection^[1].

When you have an infection, your immune system works to fight it. But sometimes your immune system stops fighting the infection and starts damaging your normal tissues and organs, leading to widespread inflammation throughout your body^[1]. This happens when an infection you already have triggers a chain reaction throughout your body^[7].

At the same time, an abnormal chain reaction in your clotting system (the process that stops bleeding) can cause blood clots to form in your blood vessels. This reduces blood flow to different organs of your body and can cause significant damage or even failure^[1].

Stages of Sepsis

Healthcare providers identify sepsis on a scale that ranges from infection and bacteremia (bacteria in your bloodstream) to sepsis and septic shock, which can lead to dysfunction of multiple organs and even death^[1].

Septic shock is the most severe stage. It is defined as sepsis with circulatory, cellular, and metabolic dysfunction that is associated with a higher risk of death^[3]. At this stage, blood pressure drops dramatically, which can damage the lungs, kidneys, liver, and other organs. When the damage is severe, it can lead to death^[3].

How Common is Sepsis?

More than 1.7 million people in the United States receive a diagnosis of sepsis each year^[1]. At least 350,000 adults who develop sepsis die during their hospitalization or are discharged to hospice^[7]. One in three people who dies in a hospital had sepsis during their hospital stay^[7].

Sepsis is more common among older adults, with rates increasing with each year after the age of 65^[1]. The risk of death from sepsis increases by an average of up to 7.6% with every hour that passes before treatment begins^[15].

Signs and Symptoms

Systemic infections and sepsis can affect many different areas of your body, so there are many possible symptoms. The clinical signs can be subtle, particularly in older adults and those who are immunocompromised^[14].

Common symptoms of sepsis include^[1][7]:

• Fever or very low body temperature (hypothermia)
• Shaking or chills
• Fast heart rate
• Low blood pressure
• Fast, shallow breathing or shortness of breath
• Confusion or changes in mental status
• Extreme pain or discomfort
• Feeling lightheaded or dizzy
• Low energy or weakness
• Warm or clammy/sweaty skin
• Reduced urination or an urge to urinate

If an infection such as blood poisoning triggered your condition, you may develop a sepsis rash on your skin. The rash makes your skin appear red and discolored. You may see small, dark-red spots on your skin^[1].

Symptoms can also be specific to the type of infection, such as painful urination from a urinary tract infection or worsening cough from pneumonia^[3]. Sepsis symptoms can vary from person to person, and sepsis may appear differently in children than in adults^[3].

When to Seek Emergency Care

Sepsis is a medical emergency. If you have any symptoms of sepsis, visit the emergency room immediately^[1]. Symptoms such as confusion or fast breathing need emergency care^[3]. Any infection that is not getting better or is getting worse requires immediate medical attention^[18].

Causes and Risk Factors

Common Causes

Bacterial infections are one of the most common causes of sepsis^[1][7]. Fungal, parasitic, and viral infections are also potential sepsis causes. Viral infections such as influenza or COVID-19 can also lead to sepsis^[7][18].

Infections that lead to sepsis most often start in the^[7]:

• Respiratory system: Infections involving your lungs, such as pneumonia
• Urinary tract: Urinary tract infections, especially likely if you have a catheter
• Gastrointestinal system: Infection of your appendix (appendicitis) or bowel problems
• Skin: Skin infections and wounds

Pneumonia is the most common cause of sepsis^[14]. Most cases of sepsis start before a patient goes to the hospital^[7].

Who is at Risk?

Sepsis can affect anyone, but people with any kind of infection are at particularly high risk^[1][7]. You are also at high risk if you^[1]:

• Are over age 65
• Are pregnant
• Have certain medical conditions like diabetes, obesity, cancer, kidney disease, or chronic lung disease
• Have a weakened immune system
• Are in the hospital for other medical reasons
• Have severe injuries like large burns or wounds
• Have catheters, IVs, or breathing tubes

Newborns and infants are another at-risk group^[1]. Most people who develop sepsis have at least one existing medical condition like chronic lung disease or a weakened immune system^[7].

How Systemic Infections Are Diagnosed

Sepsis is diagnosed through a medical assessment performed by a healthcare provider^[7]. They diagnose sepsis using physical findings such as^[7]:

• Fever
• Increased heart rate
• Low blood pressure
• Trouble breathing

Tests and Procedures

Healthcare providers perform tests that check for signs of infection or organ damage^[7]. Initial evaluation of patients with suspected sepsis includes basic laboratory tests, cultures, imaging studies as indicated, and sepsis biomarkers such as procalcitonin and lactate levels^[14].

Blood samples are commonly used to test for^[9]:

• Evidence of infection
• Blood-clotting problems
• Abnormal liver or kidney function
• Lower levels of oxygen than the body needs
• Electrolyte imbalances

Some of these tests are used to identify the germ that caused the infection that led to sepsis. This testing might include blood cultures looking for bacterial infections, fungal infections, or tests for viral infections, like influenza^[7].

Other laboratory tests to find the source of the infection might include samples of^[9]:

• Urine
• Liquid from wounds
• Mucus and saliva from the respiratory tract

If the site of infection is not readily found, your healthcare provider may order imaging tests such as X-rays, ultrasounds, CT scans, or MRI scans^[9].

Treatment

Sepsis needs treatment in hospital straight away because it can get worse quickly^[10]. Without urgent treatment, it can lead to tissue damage, organ failure, and death^[1]. Healthcare providers should immediately evaluate and treat people who might have sepsis^[7].

Antibiotics

You should get antibiotics within 1 to 6 hours of arriving at hospital^[10]. Antimicrobial therapy should be started early. Most research indicates that antimicrobial therapy should be started within three hours of presentation^[14]. The latest guidelines recommend starting antimicrobials within one hour^[14].

Physicians prescribe antibiotics (usually more than one type) based on the type of infection. Broad-spectrum antibiotics are the first-line medications. These antibiotics work against several of the more common bacteria and are given intravenously so they can get into the blood system quickly and efficiently^[15].

Fluids

Antibiotics alone will not treat sepsis; you also need fluids^[15]. Fluid resuscitation is the priority in early management^[14]. The body needs extra fluids to help keep blood pressure from dropping dangerously low, causing shock. As part of fluid resuscitation, patients with sepsis should receive an intravenous crystalloid at 30 mL per kg within the first three hours^[14].

Giving IV fluids allows healthcare staff to track the amount of fluid and to control the type of fluid. Ensuring the body has enough fluids helps the organs to function and may reduce damage from sepsis^[15].

Additional Treatments

Research shows that rapid, effective sepsis treatment includes^[7]:

• Giving appropriate treatment, including antibiotics, as soon as possible
• Maintaining blood flow to organs
• Sometimes surgery is required to remove tissue damaged by the infection

If sepsis is not treated early, it can turn into septic shock and cause your organs to fail. This is life-threatening^[10]. Vasopressor therapy is indicated if low blood pressure persists despite fluid administration. Norepinephrine is the first-line vasopressor agent for patients with septic shock^[14].

You may need other tests or treatments depending on your symptoms, including^[10]:

• Treatment in an intensive care unit
• A machine to help you breathe (ventilator)
• Surgery to remove areas of infection

You may need to stay in hospital for several weeks^[10]. Patients with severe sepsis or septic shock are usually cared for in an intensive care unit for support and close monitoring^[15].

Prevention

Preventing infections is the best way to avoid sepsis^[18]. You can take specific steps to reduce your risk of sepsis^[7][18]:

• Prevent infections by practicing good hygiene, especially washing your hands regularly
• Take good care of chronic conditions
• Get recommended vaccines
• Keep cuts clean and covered until healed
• Know the symptoms of sepsis
• Act fast if you suspect sepsis or have an infection that is not getting better or is getting worse

If hospital workers do not practice essential, basic hand washing, the hospital can be a dangerous location for contracting sepsis^[19].

Recovery and Long-term Effects

Initial Recovery

Most people make a full recovery from sepsis, but it can take time^[10]. You have been seriously ill, and your body and mind need time to get better^[16]. After you have had sepsis, rehabilitation usually starts in the hospital by slowly helping you to move around and look after yourself: sitting up, standing, walking, taking yourself to the restroom, bathing, and other activities^[16].

You may experience the following physical symptoms upon returning home^[16]:

• General to extreme weakness and fatigue
• Breathlessness
• Difficulty moving around
• Difficulty sleeping
• General body pains or aches
• Dry and itchy skin that may peel
• Weight loss, lack of appetite, food not tasting normal
• Hair loss
• Brittle nails

Emotional Effects

You might also experience the following feelings once you are at home^[16]:

• Feeling depressed, angry, or unmotivated
• Feeling anxious, more worried than usual
• Poor concentration
• Confusion about what is real and what is not
• Flashbacks or bad memories
• Nightmares or panic attacks
• Wanting to be alone, avoiding friends and family
• Frustration at not being able to do everyday tasks
• Unsure of yourself
• Not caring about your appearance

Long-term Effects

You might continue to have physical and emotional symptoms. These can last for months, or even years, after you had sepsis. These long-term effects are sometimes called post-sepsis syndrome^[10].

Many people who survive sepsis recover completely and their lives return to normal. However, as with some other illnesses requiring intensive medical care, some patients have long-term effects. These effects can include^[16]:

• Risk of amputations (loss of limb or limbs)
• Decreased mental (cognitive) functioning
• Difficulty getting to or staying asleep
• Disabling muscle and joint pains
• Kidney failure, respiratory problems
• Loss of self-esteem and self-belief
• Nightmares or panic attacks

As many as 19% of people originally hospitalized with sepsis are readmitted within 30 days and about 40% return within 90 days^[15]. Talk with a healthcare provider if you or your caregivers are concerned about any physical symptoms or feelings you are experiencing^[16]. Work with a healthcare provider to determine the most appropriate rehabilitation plan and what activities are safe for you^[16].