Asplenia

Background:

Spleen:

  • a spongy, soft organ about as big as a person’s fist, is located in the upper left part of the abdomen, just under the rib cage
  • made up of two basic types of tissue, each with different functions:
    • White pulp – part of immune system
      • produces WBCs called lymphocytes which in turn produce antibodies
    • Red pulp
      • filters blood, removing unwanted material
      • contains other WBCs called phagocytes that ingest microorganisms (e.g. bacteria, fungi, virus)
      • monitors RBCs and destroys those that are abnormal, old or damage
      • reservoir for different elements of the blood, especially WBCs and platelets
  • Able to live without a spleen
    • However… body loses some of its ability to produce protective antibodies and to remove unwanted microorganisms from the blood
      = impaired immune system
    • Particularly at risk of infection by encapsulated bacteria e.g. Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae
  • If spleen is injury, may expect PLTs to increase (more crucial to be on VTE Px)

Splenectomy:

  • Surgical removal of spleen

Case: KK is a 21 yo female (wt = 72kg, ht = 167 cm) who was diagnosed with a mid-body pancreatic neuroendocrine tumour (>2cm)  had a laparascopic (minimally invasive) distal pancreatectomy and splenectomy

  • WBC are elevated post-op since patient no longer has spleen which cleans out WBC
  • Received pre-op splenic vaccinations and on October 5: Prevnar 13, Oct 8/9: Tetanus and Meningitis
  • Surgery – Oct 14, 2016 (patient did not get dose 14 days pre-op → might not be fully protected by vaccinations on date of surgery)
  • T 36.7, RR 12-16, HR 70, O2sats 99% RA
  • Pre-op received 1 dose of cefazolin 2g IV

Post-Op Management:

Infection Risk:

I. Antibiotics

Daily prophylaxis:

  • Do not recommend routine prophylaxis in asplenic adults

General pre-op prophylaxis (RCH): (against G+ pathogens in skin)

  • Administer 60 mins or less prior to skin incision
    • Cefazolin 2g IV
    • Cefazolin 2g IV and metronidazole 500mg IV
  • >120kg:
    • Cefazolin 3g IV
    • Cefazolin 3g IV and metronidazole 500mg IV
  • Significant penicillin/cephalosporin allergy:
    • clindamycin 900mg IV
    • metronidazole 500mg IV
    • gentamicin (5mg/kg, round to closest 20mg) mg IV
      • If body weight is 20% above IBW, gentamicin dose should be adjusted.
    • Ciprofloxacin 400mg IV. If renal dysfunction precludes use of genatmicin
  • For patients with known MRSA colonization:
    • Vancomycin (15mg/kg IV, round to closest 250mg IV).

II. Vaccinations recommendations for adults with anatomical or functional asplenia:
Risk for overwhelming postsplenectomy sepsis (0.05% to 2% incidence in splenectomy – source: http://www.surgicalcriticalcare.net/Guidelines/splenectomy_vaccines.pdf)

Recommendations:

Vaccines can either be started 14 days pre-op or 14 days post-op

Pneumonia:

  • 13-valent Pneumonia Conjugate Vaccine (PCV13) 0.5mL IM x 1 d0se
  • 23-valent Pneumonia Polysaccharide Vaccine (PPSV23) 0.5mL IM x 1 dose
    • 8 weeks after PCV13
  • Repeat vaccinations every 5 years

Meningitis:

  • Meningococcal quadrivalent conjugate vaccine 0.5mL IM x 1 dose
  • Repeat above dose 2 months after 1st dose
  • Repeat vaccinations every 5 years

Influenza vaccine

  • Repeat inactivated influenza vaccine annually

H. influenzae type B vaccine

  • H. influenzae type B vaccine 0.5 mL IM x 1 dose

Anti-coagulation:

General pre-op VTE prophylaxis (RCH):

  • Minor surgery procedures: Heparin 5000 units SC 60-90 mins pre-op
  • Major surgery procedures prophylaxis to be given in OR by anesthesiology after consideration of epidural

General post-op VTE prophylaxis (RCH):

  • All patients requiring major surgical procedures → moderate or high risk
  • Give 1st post-op dose:
    • Heparin 5000 units SC one dose evening at surgery (POD 0), then on POD 1 change to dalteparin 5000 units SC once daily in morning until discharged
    • For patients with severe renal impairment, heparin 5000 units SC Q12H starting evening of surgery, continue until discharged. CBC on POD 1, 2 and 3

VTE prophylaxis (treat with LMWH):

  • Generally 10-14 days
  • Pelvic or abdominal surgery → 4 weeks
    • High risk, as per special authority:
      • previous hx of VTE
      • anaesthesia time > 2 hrs
      • bed rest > 4 days

Case Recommendations:

  • After Dec 3, get:
    PPSV 23, Hib, Meningitis Conjugate, Influenza x 1 dose
  • Dalteparin 5000 units SC daily until Nov 12, 2016 (inclusive)

References:

Image result for spleen awkward yeti