TY  - CHAP
M1  - Book, Section
TI  - Infections in Immunocompromised Patients
A1  - Mueller, Scott W.
A1  - Fish, Douglas N.
A2  - DiPiro, Joseph T.
A2  - Yee, Gary C.
A2  - Posey, L. Michael
A2  - Haines, Stuart T.
A2  - Nolin, Thomas D.
A2  - Ellingrod, Vicki
PY  - 2020
T2  - Pharmacotherapy: A Pathophysiologic Approach, 11e
AB  - KEY  CONCEPTS  An  immunocompromised  host  is  a  patient  with  defects  in  host  immune  defenses  that  predispose  to  infection.  Risk  factors  include  neutropenia,  immune  system  defects  from  disease  or  immunosuppressive  drug  therapy,  compromise  of  natural  host  defenses,  environmental  contamination,  and  changes  in  normal  flora  of  the  host.  Immunocompromised  patients  are  at  high  risk  for  a  variety  of  bacterial,  fungal,  viral,  and  protozoal  infections.  Bacterial  infections  caused  by  gram-positive  cocci  (staphylococci  and  streptococci)  occur  most  frequently,  followed  by  gram-negative  bacterial  infections  caused  by  Enterobacteriaceae  and  Pseudomonas  aeruginosa.  Fungal  infections  caused  by  Candida  and  Aspergillus,  as  well  as  certain  viral  infections  (herpes  simplex  virus  [HSV],  cytomegalovirus  [CMV]),  are  also  important  causes  of  morbidity  and  mortality.  Risk  of  infection  in  neutropenic  patients  is  associated  with  both  the  severity  and  duration  of  neutropenia.  Patients  with  severe  neutropenia  (absolute  neutrophil  count  less  than  500  cells/mm3  [0.5  ×  109/L])  for  greater  than  7  to  10  days  are  considered  to  be  at  high  risk  of  infection.  Fever  (single  oral  temperature  of  greater  than  or  equal  to  38.3°C  [100.9°F],  or  a  temperature  of  greater  than  or  equal  to  38°C  [100.4°F]  for  greater  than  or  equal  to  1  hour)  is  the  most  important  clinical  finding  in  neutropenic  patients  and  is  usually  the  stimulus  for  further  diagnostic  workup  and  initiation  of  antimicrobial  treatment.  Infection  should  be  considered  as  the  cause  of  fever  until  proven  otherwise.  Usual  signs  and  symptoms  of  infection  may  be  altered  or  absent  in  neutropenic  patients.  Appropriate  empiric  broad-spectrum  antimicrobial  therapy  must  be  rapidly  instituted  to  prevent  excessive  morbidity  and  mortality.  Empiric  antimicrobial  regimens  for  neutropenic  infections  should  take  into  account  patients’  individual  risk  factors,  as  well  as  institutional  infection  and  susceptibility  patterns.  The  significant  morbidity  and  mortality  associated  with  gram-negative  infections  require  that  initial  empiric  regimens  for  treatment  of  febrile  neutropenia  have  good  activity  against  P.  aeruginosa  and  Enterobacteriaceae.  Parenteral  regimens  most  commonly  recommended  for  initial  inpatient  treatment  include  monotherapy  with  an  antipseudomonal  β-lactam,  or  a  combination  regimen  consisting  of  an  antipseudomonal  β-lactam  plus  an  aminoglycoside.  Low-risk  patients  may  be  successfully  treated  with  oral  antibiotics  (fluoroquinolone  plus  amoxicillin-clavulanate),  with  the  treatment  setting  determined  by  the  patient’s  clinical  status.  Neutropenic  patients  who  remain  febrile  after  3  to  5  days  of  initial  antimicrobial  therapy  should  be  reevaluated  to  determine  whether  treatment  modifications  are  necessary.  Common  regimen  modifications  include  addition  of  vancomycin  (if  not  already  administered)  and  antifungal  therapy  (amphotericin  B,  an  echinocandin,  or  fluconazole).  Therapy  should  be  directed  at  causative  organisms,  if  identified,  but  broad-spectrum  regimens  should  be  maintained  during  neutropenia.  The  optimal  duration  of  therapy  for  febrile  neutropenia  is  controversial.  The  decision  to  discontinue  antimicrobials  is  based  on  resolution  of  neutropenia,  defervescence,  culture  results,  and  clinical  stability  of  the  patient.  Prophylactic  antimicrobials  are  administered  to  cancer  patients  expected  to  experience  prolonged  neutropenia,  as  well  as  to  hematopoietic  stem  cell  and  solid-organ  transplant  recipients.  Prophylactic  regimens  may  include  antibacterial,  antifungal,  antiviral,  or  antiprotozoal  agents,  or  a  combination  of  these,  selected  according  to  risk  of  infection  with  specific  pathogens.  Optimal  prophylactic  regimens  should  consider  individual  patient  risk  for  infection  and  institutional  infection  ...
SN  - 
PB  - McGraw-Hill Education
CY  - New York, NY
Y2  - 2024/04/16
UR  - accesspharmacy.mhmedical.com/content.aspx?aid=1182471184
ER  -