Neutropenic Fever

Neutropenic fever, also known as febrile neutropenia, is the presence of neutropenia accompanied by a fever. Neutropenia refers to a decrease in the concentration of neutrophils in blood. Neutrophils are a type of white blood cell that helps fight infections as part of the immune system. 

Chemotherapy is one of the most common causes of neutropenic fever, as many chemotherapy medications that destroy tumor cells can also affect the normal production of blood cells, known as hematopoiesis, resulting in myelosuppression and destruction of neutrophils.

To prevent the neutrophil count from decreasing further, chemotherapy dosage may need to be reduced or delayed, which, in turn, can adversely affect the prognosis.

In the presence of neutropenia, the usual signs and symptoms of infection may be reduced or absent, and often, fever is the only reliable symptom. Other significant signs and symptoms of infection can include abdominal pain, mucositis of the gastrointestinal tract, and perirectal pain.

Diagnosis of neutropenic fever involves evaluating individuals for their clinical presentation, including the duration of their fever and any additional symptoms, as well as determining possible sites of infection and causative pathogens. A review of medical history should include recent antibiotic therapy, surgery, invasive procedures, past infections, and potential exposure to infected visitors, pets, plants, or contaminated foods. 

Any potential portal of entry for pathogens should be carefully examined, including the skin, mucous membranes, gastrointestinal tract, urinary tract, and any IV catheters or line sites.

Laboratory tests and cultures help determine the causative pathogens. Laboratory tests include a complete blood cell count and differential white cell count to determine the severity of neutropenia. Cultures may involve blood culture sets, a urinalysis, and cultures from other possible sites of infection, such as from the stool, sputum, or nasal swab. 

Finally, individuals with neutropenic fever should be examined with chest X-rays, and depending on the clinical presentation, some individuals may need additional imaging studies, such as a CT scan.

Individuals diagnosed with neutropenic fever should be evaluated to determine their risk of developing medical complications, such as severe sepsis or septic shock. 

Treatment begins with an immediate evaluation, risk assessment for complications, and blood cultures to find the causative bacteria. Then, individuals are given broad-spectrum empiric antibiotic therapy. Low-risk patients are commonly given oral antibiotics, while high-risk patients generally get intravenous antibiotics. 

Although infection with Gram-positive bacteria is more common, infection with Gram-negative bacteria is associated with higher morbidity and mortality, so using antipseudomonal beta-lactam agents like piperacillin-tazobactam is preferred. Individuals with hypotension or septic shock may require a multidrug approach, combining more than one antibiotic until blood culture results come back.

Preventing neutropenic fever begins by taking steps to limit exposure to opportunistic pathogens. Measures include daily baths, oral hygiene, routine inspection of the skin and other portals of entry, cleaning and cooking food well, as well as avoiding contact with pets, plants, and visitors with active infections. Additionally, with hospitalized patients, healthcare workers and caregivers should practice standard precautions, including regular hand hygiene and utilizing personal protective equipment, as well as limiting skin breaks or injury by avoiding rectal thermometers, enemas, suppositories, digital rectal examinations, and invasive procedures.

Additional measures can involve giving preventive therapy with colony-stimulating factors that stimulate the bone marrow to increase the production of white blood cells like neutrophils. These agents are administered according to clinical practice guidelines developed by the American Society of Clinical Oncology as a prophylactic treatment in high-risk patients for primary prophylaxis or secondary prophylaxis, or as a combination with antibiotic therapy during active infection with neutropenic fever.