Infections in Immunocompromised Patients

Why do immunocompromised patients get more infections than other patients?

The body’s immune system uses a number of defenses to prevent or get rid of infection. Infection can be caused by a variety of organisms such as bacteria, viruses or fungi. The immune system can be weakened (immunocompromised) by a number of diseases and their treatments. These are some examples of what can weaken the body’s immune defenses:

• Breakdown of the skin, lining of the mouth or the rest of the gastrointestinal tract. This may occur as a side effect of medicine, because of radiation used for cancer treatment, or other reasons.
• Lower numbers of infection-fighting cells such as white blood cells. This can be caused by certain cancers or as a side effect of medicines used for cancer treatment.
• Presence of foreign objects such as venous (vein) or urinary catheters (tubes). Patients with these devices must be careful to avoid infection.

Why are infections dangerous in immunocompromised patients?

• The usual symptoms may be absent. Patients with weak immune systems may not show the classic signs of infection such as redness and swelling at the infection site. Sometimes the only symptom of an infection may be fever.
• The infection may move quickly. In the absence of infection-fighting white blood cells, the infection may rapidly progress from fever alone to sepsis and death. For this reason patients with weak immune systems who have low white blood cell counts are asked to report if they have fever right away. These patients are often hospitalized if they get a fever, so they can receive treatment with intravenous (IV) antibiotics.
• Their systems may not respond quickly to infection. Patients with weak immune systems may have trouble clearing infections from their bodies. For example, a viral infection such as the “flu” may take longer to clear from a patient with a weak immune system compared to a person with a healthy immune system.

How can infections in immunocompromised patients be prevented?

These are the general principles of preventing infection in patients with weak immune systems:

• Practice good hand hygiene. Many infections are spread from bacteria or viruses that we pick up on our hands when we touch people or objects around us. Cleaning hands often (washing with soap and water or using alcohol-based hand sanitizer) is the best way to prevent the spread of infection.
• Avoid contact with people who are sick. Even a common cold virus can make a patient with a weak immune system very sick.
• Get vaccinated. Care providers for patients with weak immune systems should receive all recommended vaccinations, including influenza and pertussis vaccines. Patients should also receive these vaccines as long as their doctors recommend it.

What are the survival rates for patients with weak immune systems who get an infection?

Because so many different diseases, conditions and infections can occur in patients with weak immune systems, no broadly useful survival rates are available.

In general, the survival outlook for patients with weak immune systems who develop infections depends on the reason why the immune system is compromised and the type of infection present.

Preventing and aggressively treating infections are critical steps to ensure successful cancer treatment.