Continuing Education Activity

Neutropenic fever is defined as a single oral temperature greater than or equal to 101 F, or a temperature greater than or equal to 100.4 F for at least an hour, with an absolute neutrophilic count (ANC) of less than 1500 cells/microliter. In severe neutropenia, the absolute neutrophil count (ANC) is less than 500 per microliter, or ANC is expected to decrease below 500 cells/microL in the next 2 hours. Febrile neutropenia is the most common serious and common complication of cancer therapy. This activity reviews the management and highlights the tools needed by an interprofessional team to evaluate patients with febrile neutropenia properly.

Objectives:

• Review the etiology of febrile neutropenia.
• Identify indexes used to assess patients with febrile neutropenia.
• Describe the workup for patients with febrile neutropenia.
• Review the importance of communication and urgency amongst the interprofessional team to improve the outcome in patients with febrile neutropenia.

Introduction

Neutropenic fever is when there is a single oral temperature greater than or equal to 101 F, or a temperature greater than or equal to 100.4 F for at least an hour, with an absolute neutrophilic count (ANC) of less than 1500 cells/microliter.[1] In severe neutropenia, the ANC is less than 500 per microliter or ANC that is expected to decrease below 500 cells/microL in the next 2 hours. In profound neutropenia, the ANC is less than 100 cells/microliter. To calculate ANC, multiply the total white blood cell (WBC) count by the percentage of polymorphonuclear cells (PMNs) and band neutrophils.[2]

Etiology

In most cases, the infectious etiology is unable to be determined and gets marked as a fever of unknown origin (FUO). The definition of FUO is neutropenic cases with a fever greater than 38.3 C, without any clinically or microbiologically defined infection.[3][4] Documented infections only comprise approximately 30% of cases. However, infections are the primary cause of morbidity and mortality in patients with cancer who present with fever and neutropenia.[3] The majority of infections are bacterial, but viral or fungal etiology is possible.[5] Common bacterial pathogens include gram-positive bacteria infections such as Staphylococcus, Streptococcus, and Enterococcus species.[5] Drug-resistant organisms, including Pseudomonas aeruginosa, Acinetobacter species, Stenotrophomonas maltophilia, Escherichia coli, and Klebsiella species, have also been identified as infectious agents.

Epidemiology

The specific frequency of agranulocytosis is unknown; It is estimated to be 1.0 to 3.4 cases per million people per year. Neutropenia was particularly associated with HIV infection, acute leukemias, and myelodysplastic syndromes. Drug-induced neutropenia has an incidence of one case per million persons per year. About 50% of patients with febrile neutropenia will develop an infection, of which 20% with profound neutropenia will observe bacteremia.[6]

Pathophysiology

Neutropenic fever is the most common and serious complication associated with hematopoietic cancers or with patients receiving chemotherapeutic regimens for cancer. Neutropenic fever occurs when a neutropenic patient encounters an infectious pathogen. In this immunocompromised state, patients lose or have weakened immunity to fend off infections. The host barriers, such as the mucosal lining of the GI tract or sinuses, may be damaged, leading the host open to invasion from an infectious pathogen.[7] About 1% of patients undergoing chemotherapy and radiation experience this complication.[8]

History and Physical

A detailed history of the patients presenting illness, chemotherapy treatment, medication use, previous history of infections, especially with bacterial resistant organisms, and the presence of allergies, should be noted to guide your therapy.[8] Signs of infection may require assessment; Pain and tenderness may be the only indicators of infection. Significant risk factors for the development of febrile neutropenia include older age, comorbidities, the specific type of cancer, and the type and number of myelosuppressive chemotherapy agents in use.[9]

Evaluation

Lab tests should be ordered; complete blood count to determine the patient's neutropenic level; blood, urinalysis, and throat cultures are needed to determine the source of infection. Two sets of blood cultures should be obtained from a peripheral vein and any venous catheters, as well as specimens for testing from any sites of infection, before the immediate administration of empirical broad-spectrum antimicrobial therapy. Urinary tract infections should be suspected in asymptomatic patients with a history of such infections.[8] If diarrhea is present, a sample may be checked. If the patients have any respiratory symptoms, a chest x-ray is necessary.

Two widely used assessment tools, The Multinational Association for Supportive Care in Cancer (MASCC) and The Clinical Index of the Stable Febrile Neutropenia (CISNE) can be part of the patient interview. These tools can help to risk-stratify patients into a high-risk and low-risk neutropenic fever.

The MASCC was created the assess the risk of serious complications in patients with neutropenic fever. The MAASC index has a max score of 26. Patients with a score greater than 21 are considered low risk, and less than 21 are high risk.[10]

MASCC Scoring Index

Characteristic/Score

• The burden of illness: no or mild symptoms/5
• The burden of illness: none or mild/5
• The burden of illness: moderate symptoms/3
• The burden of illness: severe symptoms/0
• No hypotension (systolic BP greater than 90 mmHg)/5
• No chronic obstructive pulmonary disease/4

Type of Cancer

• Solid tumor/4
• Lymphoma with previous fungal infection/4
• Hematologic with previous fungal infection/4
• No dehydration/4
• Outpatient status (at the onset of fever)/3
• Age less than 60 years/2

A more specific scale for low-risk patients classification is the CISNE and may be more useful in the emergency department setting.[5] One of the components of the scale is the Eastern Cooperative Oncology Group (ECOG) Performance Status, which helps determines the patient’s functional status as a surrogate for the patient’s ability to undergo therapies in serious illnesses.

The Clinical Index of Stable Febrile Neutropenia Score

Characteristics/Score

• ECOG performance status (greater than 2)/2
• Chronic obstructive pulmonary disease (COPD)/1 
• Stree-induced hyperglycemia/2
• Chronic cardiovascular disease/1
• Monocytes less than 200 per mcL/1
• Grade greater than or equal to 2 mucositis/1
• Interpretation

CISNE/Recommendation

• 0-2/Consider outpatient management with oral antibiotics
• Greater than or equal to 3/inpatient management

Treatment / Management

In low-risk patients, oral empiric therapy with a fluoroquinolone plus amoxicillin/clavulanate is recommended in the outpatient setting.[6] Clindamycin can be used for those with penicillin allergies. If the patient remains febrile for 48 to 72 hours, the patient will require admission.[5]

For high-risk patients presenting with neutropenic fever, an intravenous antibiotic therapy should be given within 1 hour after triage and be monitored more than 4 hours before discharge. The Infectious Disease Society of America (IDSA) recommends monotherapy with antipseudomonal beta-lactam agents such as cefepime, carbapenems, or piperacillin and tazobactam.[5] Vancomycin is not recommended for initial therapy but should be considered if suspecting catheter-related infection, skin or soft tissue infections, pneumonia, or hemodynamic instability.[11] If patients do not respond to treatments, coverage should be expanded to include resistant species[5][1][12][13][14]:

• Methicillin-resistant Staphylococcus aureus (MRSA): vancomycin, linezolid, and daptomycin
• Vancomycin-resistant enterococci (VRE): linezolid and daptomycin
• Extended-spectrum beta-lactamase (ESBL)-producing organisms: carbapenems
• Klebsiella pneumoniae: carbapenems, polymyxin, colistin, or tigecycline

Recommendation for prevention of infection in neutropenic patients:

• Fluoroquinolones as prophylaxis for patients who are high risk
• Antifungal prophylaxis with an oral triazole with patients with profound neutropenia
• Trimethoprim-sulfamethoxazole (TMP-SMX) is the recommended treatment for patients receiving chemotherapy regimens associated with greater than 3.5% risk for pneumonia from Pneumocystis jirovecii
• Yearly influenza vaccination is recommended for all patients receiving chemotherapy.
• Treatment with a nucleoside reverse transcription inhibitor is recommended for patients at high risk of hepatitis B virus reactivation.
• Herpes simplex virus- seropositive patients undergoing allogeneic HSCT or leukemia induction therapy should receive prophylaxis.

In the National Comprehensive Cancer Network (NCCN) guidelines, it is recommended that patients at a high risk of neutropenic fever can benefit from granulocyte-colony stimulating factors (G-CSFs).[15]

Differential Diagnosis

• Transfusion reaction
• Medication allergies and toxicities
• Tumor-related fever

Prognosis

Researchers have several prognostic factors, and there is controversy surrounding prognostic factors. Hematological parameters, prophylactic measurements, and individual patient risk factors have yielded inconsistent results. The MASCC risk-index score, originally designed to identify low-risk patients, showed a lower MASCC score correlated with a poorer prognosis of febrile neutropenia. Very low levels (<15) demonstrated a high rate of complications. Patients with severe sepsis and septic shock commonly had procalcitonin concentrations greater than 2.0 ng/ml, which merits consideration for an increased likelihood of poor prognosis.[16]

Complications

Most patients with chemotherapy-induced febrile neutropenia recover rapidly without serious complications. However, it remains a life-threatening, treatment-related, toxicity and correlates with chemotherapy dose reductions and delays in continuing chemotherapy, potentially compromising treatment outcomes.[16]

Deterrence and Patient Education

Chemotherapy patients should be counseled regarding the potential for developing febrile neutropenia, including education on the symptoms for which they must watch. If they develop neutropenia, they need to avoid exposure to persons with respiratory infections, as well as crowded places. If their ANC falls below 1000/microL, they should wear a facemask in public places. Taking their temperature daily is also recommended, especially if they develop symptoms such as chills, sweats, or feeling feverish.

Enhancing Healthcare Team Outcomes

Febrile neutropenia is an oncological emergency that requires a team of infectious disease specialists, emergency medicine, oncology, pharmacy, and specialty-trained nurses and pharmacists for proper management, working as a collaborative interprofessional team. [Level 5] The most important determining factor of patient outcomes is the timing of administrating IV antibiotics. Early admission of antibiotics has been shown to reduce mortality and the hospital length of these patients.[17][18] [Level 3] A heightened sense of urgency should be present in all staff members when interviewing patients undergoing chemotherapy presenting with new-onset fever. The pharmacist should assist the team with antibiotic selection and dosing. The nursing staff should monitor the patient and report any concerns or changes in condition to the team. The best outcomes are achieved by an interprofessional team approach to diagnosing and managing this life-threatening condition. [Level 5]