Neutropaenic sepsis

What is Neutropaenic sepsis?

Neutropaenic sepsis is a systemic infection that occurs in the setting of decreased blood neutrophils (granulocytes). A decrease in neutrophils increases the risk of infection, and once microorganisms have entered the body, reduces the body's ability to fight the infection. Many microorganisms, including some that don't usually cause infections, may proliferate in these patients and cause disseminated infection.

Statistics on Neutropaenic sepsis?

Up to 48.3% of neutropaenic cancer patients suffer infections and 21% of patients with cancer who experience neutropaenic fever will suffer serious complications. Neutropaenic sepsis carries an overall 4-30% mortality rate in cancer patients.

Risk Factors for Neutropaenic sepsis

Cancer patients may suffer neutropaenia as a result of their disease, for example leukaemia, but the most common causes are chemotherapy and radiotherapy. Most chemotherapy agents are myelosuppressive, meaning they suppress bone marrow function and thus production of white blood cells including neutrophils.

Progression of Neutropaenic sepsis

Neutropaenia increases the susceptibility of the body to bacterial infection. Patients with neutropaenia alone (i.e. no other white blood cell deficits) are not at increased risk of parasitic or viral infections. Prolonged neutropenia also increases the risk of systemic fungal infection. The most common infections seen in neutropaenic patients are skin infections, including ulcers, abscesses and rashes that are slow to heal. Signs of infection such as warmth and swelling may be absent, as these are usually mediated by neutrophils. Neutropaenic sepsis is when an infection enters the blood, often from a skin or gastrointestinal source, and becomes systemic. This is dangerous as many organ systems may be affected and the infection can worsen quickly. Neutropaenic patients are susceptible to infections with the following bacteria: Staphylococci, Streptococci, Enterococci, Pseudomonas aeruginosa, Aeromonas hydrophila, Bacillus species, Corynebacteria and Enterobacteriaciae. Fungi from the species Candida, Aspergillus and Fusarium can also cause infection.

How is Neutropaenic sepsis Diagnosed?

Signs and Symptoms of Sepsis:

increased heart rate
decreased blood pressure
pale, clammy skin
rapid, shallow breathing
general weakness

If the sepsis becomes severe and the patient goes into septic shock, they may suffer the above symptoms more seriously, as well as:

decreased urine output
breathing difficulties requiring oxygen, intubation or even mechanical ventilation
altered blood clotting (uncontrolled clots and bleeds)
disorientation and confusion
jaundice
changes in blood sugar resulting in hyperglycaemic or hypoglycaemic coma

However, with early detection and treatment, neutropaenic fever rarely progresses to sepsis and the patient fully recovers.

Prognosis of Neutropaenic sepsis

With early detection and treatment, there is rarely a progression to sepsis and the patient fully recovers.

How is Neutropaenic sepsis Treated?

Empirical antibiotic therapy is vital to the treatment of a neutropaenic patient who becomes febrile. This is particularly useful in preventing deaths due to gram-negative organisms, but treatment covering both gram-positive and gram-negative organisms is required. There is no doubt as to the value of empirical antibiotics, but debate continues as to the best regime. Currently the Therapeutic Guidelines recommend gentamicin + ceftazidime or ticarcillin/clavulanic acid. Monotherapy with ceftazidime, cefepime, meropenem or imipenem has also proven effective. All of these drugs should be used at maximum recommended dosage. Vancomycin is indicated if a resistant gram-positive organism is isolated. Ideally, each patient should be approached individually, with attention paid to recent infections and antibiotic exposure, when deciding on an empirical antibiotic regime.