circumferential palpation Do not perform a digital rectal examination or measure a rectal temperature as it may increase the risk of bacteremia Diagnostic testing should include a CBC with differential and blood cultures from all line lumens or via venipuncture in patients without a line Institution-specific guidelines should be followed regarding the need for peripheral blood cultures in addition to line cultures, and if additional orders or specimens are needed for anaerobic cultures Additional diagnostic testing can be obtained as needed after empiric antibiotics are started A chest x-ray should be obtained in patients with respiratory symptoms A urinalysis is not valuable for screening for infection since there are too few WBCs for the leukocyte esterase to be of value A urine culture should be obtained as long as it does not delay start of antibiotics or require catheterization, which may also increase the risk of bacteremia If the patient has a history of urinary tract infections, the risk of urinary catheterization may be justified Throat cultures may be of value if there are focal findings involving only the pharynx and/or tonsils but are rarely informative in a patient with diffuse mucositis Specific imaging may be of value based on physical findings Viral testing of vesicular lesions may identify varicella infections Cultures of draining abscesses or wounds may help guide antibiotic choice Diarrhea should be tested for C difficile toxin Management Antimicrobial treatment of suspected febrile neutropenia should be initiated within hour of patient arrival with the institutional standard regimen Therapy should be directed against both gram-positive and gram-negative organisms, including opportunistic pathogens ( Fig 98.4 ) Specific coverage, in addition to empiric therapy, is indicated for several clinical settings Third-generation cephalosporins may have inadequate gram-positive coverage for patients with soft tissue site infections and consideration should be given to a semisynthetic penicillin and an aminoglycoside or the addition of vancomycin, given the rising incidence of MRSA With evidence of sepsis, double coverage for gram-negative organisms may be added in addition to vancomycin to cover for possible Streptococcus viridans, especially in patients with advanced hematologic malignancies Fungal coverage is often considered for patients in shock Empiric antibiotics for suspected typhlitis include broad-spectrum coverage of gram-negative enteric flora as well as specific anaerobic coverage and should be started as soon as the diagnosis is suspected Typical regimens are a carbapenem alone or a combination regimen such as piperacillin/tazobactam with gentamicin or ceftazidime with metronidazole Laboratory studies should include coagulation studies and lactic acid, as well as CBC with differential and basic chemistries to assess hydration and renal function Uncontrolled coagulopathy and/or acidosis are