1. Post splenectomy infection
Dr. M. Shahparianpour

3. Spleen

5. consists of the capsule and trabeculae which enclose the pulp.
3 zones of the pulp
a. White pulp – lymph node; contains lymphocytes, macrophages, and plasma cells in a reticular network
b. Red pulp – consists of the cord and sinuses; contains the cellular elements of the blood
c. Marginal zone – poorly defined vascular space between pulps; contains sequestered foreign material and plasma as well as abnormal cellular elements

6. histology

7. The role of the spleen in the prevention of bacterial infections

8. It acts as an endothelial filtration organ for bacteria and other foreign material through:
phagocytosis and the production of opsonins including antigen-specific IgM, alternate complement components, properdin, and tuftsin
One of its most important immune functions is responding to blood-borne particulate antigens in the nonimmune host.
The spleen provides the most effective primary IgM response to encapsulated bacteria

9. There also seems to be a relationship between the quantity and quality of spleen and protection against sepsis:
splenic function after subtotal splenectomy for splenic injury is preserved and may be adequate to prevent severe postsplenectomy sepsis
The propensity for pneumococcal infections in patients with sickle cell disease underscores the importance of qualitative splenic function to protect against sepsis

10. Etiology of asplenia and hyposplenia

11. Asplenia refers to the absence of the spleen.
The most common cause of asplenia is surgical removal of the spleen:
Hypersplenism accounts for up to 50% of splenectomies, whereas trauma accounts for 10% to 30%

13. Hyposplenism refers to a poorly functioning, but intact spleen
A rare cause of asplenia is congenital agenesis of the spleen.
This may occur as an isolated finding or as part of a syndrome often associated with cardiovascular abnormalities, such as Ivemark’s syndrome.
Hyposplenism refers to a poorly functioning, but intact spleen

14. Functional asplenia Autoimmune Disease PBC SLE Sjogrens
Intestinal Disorder
Celiac disease
Crohn’s UC
Haematological Disease
Sickle cell
Essential thrombocytopenia
Infiltrative Disease
Amyloid
Sarcoidosis
Neoplasia
Breast Cancer
Haematological malignancy
Miscellaneous
Alcoholism
BMT
TPN
Splenic Thrombosis

16. The risk of developing severe infection remains a significant complication of asplenia (surgical splenectomy or congenital asplenia) and hyposplenia, especially in children under the age of 5 years

17. Splenic salvage methods (eg, partial splenectomy) are practiced with specific indications, the goal being to preserve some of the splenic immune function.
Whether partial splenectomy renders the same risk of developing overwhelming postsplenectomy sepsis (OPSS) as total splenectomy and whether the same preventative measures should be taken, remain unclear.

18. Definition of OPSI
OPSI may have a short prodrome with non-specific symptoms
Evolve into septic shock and DIC
Clinical course measured in hours rather than days
Fever most common – most report rigors days prior to presentation
In adults OPSI usually cryptic infection without primary source

19. It is well known that asplenia or hyposplenia convey an increased lifetime risk of developing severe infections to an affected individual, regardless of:
age,
the cause of asplenia or hyposplenia,
in the case of splenectomy, the duration of time from removal of the spleen

20. the incidence seems to be related to age and underlying disease :
Splenectomized children under the age of 15 years are at greater risk of developing OPSS than adults
The incidence of OPSS is higher in children with
underlying hemoglobinopathies (thalassemia major and sickle cell disease) and hereditary spherocytosis than in those who undergo splenectomy because of trauma

21. Low risk Intermediate risk High risk
Risk of OPSI can be stratified according to underlying disease
Low risk
Trauma
Intermediate risk
Spherocytosis
ITP
Portal Hypertension
High risk
Thalassaemia
sickle cell disease
Hodgkin's Disease
Malignancy

22. Risk of post splenectomy sepsis low but carries high risk of death (50-80%)
If patients are educated to seek attention immediately may be reduced to about 10%
More than 50% who die do so within 48 hours of admission

23. Children: 1/175 patient years Adults: 1/400~500 patient years
Highest risk at first few years
1/3 at first year
1/2 at first 2 years
However, 1/3 after first 5 years
Can happen even 20 years after splenectomy

25. Clinical manifestations
Fever
Any fever must be viewed as possible PSS
Bacteremia
Coagulopathy
Purpura, petechiae
Meningitis
Headache, neck stiffness, seizure
Respiratory symptoms
Cough, dyspnea, respiratory failure
GI symptoms
Nausea, vomiting, diarrhea, GI bleeding
Shock

26. The mortality rate of sepsis associated with asplenia or hyposplenia remains high; death occurs in 50% to 70% of those afflicted
Mortality rates are also age related, with the highest rates reported in those children less than 2 years of age

27. Common pathogens Encapsulated pathogen
Streptococcus pneumoniae(50~60 %)
No particular serotype is more common
Haemophilus influezae(20~30 %)
Neisseria spp.(10~20 %)
Other uncommon pathogens:
Capnocytophaga canimorsus
Common flora in oral cavity of dogs and cats
Bordetella holmesii

28. Capnocytophaga canimorsus

29. LAB
CBC
Blood smear
DIC profile
Lumbar puncture
CXR
Blood culture

30. Management Braod-spectrum antibiotics General suggestion
Based on expert opinion
Must cover:
penicillin-resistant pneucoccus
beta-lactamase producing H.influenzae
General suggestion
Ceftriaxone + Vancomycin
Levofloxacin + Vancomycin
Life-support measures
H/D or CVVH for ARF
Ventilator
Inotropic agents
Fluid

31. Prevention Avoid unnecessary splenectomy Immunization Timing
14 days before splenectomy
14 days after splenectomy (not immediately)
Pneumococcal vaccine
PPV-23 for adults
PCPV-7 for children and some adults
Haemophilus B vaccine
Meningococcal vaccine
Re-immunization
Other vaccines: influenza vaccine

32. Antibiotic prophylaxis
Daily penicillin
Reduce incidence by half
Reduce mortality by 80 percents
Life-long or 3~5years?
Post PSS patients
Abx for fever
On hand
Empirical: Augmentin, Cefuroxine, fluoroquinolones
When fever, Take the drug and go to doctor without delay
Abx for dental procedures
Not recommended for no obvious advantage

33. Absent or dysfunctional spleen in adults
Immunisation
Travel †
Antibiotics
Antibiotic prophylaxis (adult dose)
Penicillin V 500mg b.d.
Amoxycillin 500mg bd
(Erythromycin 250mg od if penicillin allergy)
HiB Vaccine
Previously non immunised adults should receive a single dose of vaccine.
Pneumococcal vaccine
Polysaccharide vaccine (Pneumovax). Avoid in pregnancy.
Meningitis C vaccine
Previously non immunised adults should receive a single dose of vaccine
Influenza
Annual
vaccine
Anti-malarials
if travelling to endemic areas
Meningitis A+C,W135,Y
if appropriate
Antibiotics‡
Check antibodies 4/52 post vaccination
Antibiotic cover
3 day supply of Amoxycillin should be kept by the patient with instructions to take 1gm at first sign of infection and 500mg tds thereafter and to seek immediate medical attention.
Poor response revaccinate and re-test at 4/52
Good response recheck antibody titre in 1 year
If poor response give conjugate (Prevenar) if not already given.
†Discuss with Adult Infectious Disease team
‡Antibiotic prophylaxis may need altering depending upon local resistance.

34. Lack of splenic clearance of leads to high parasitaemia
Malaria
Lack of splenic clearance of leads to high parasitaemia
Increased risk of fulminant malaria

35. Antibiotic Prophylaxis
1. All patients, regardless of underlying condition,
should be on lifelong antibiotic prophylaxis. This
should be either Penicillin V or Amoxycillin, with a preference for Penicillin V.
Adult doses:
Penicillin V 500 mg b.d.
Amoxycillin 500 mg o.d.
2. For penicillin allergic patients, Erythromycin 250 mg
b.d. should be used.
3. Patients travelling to areas where penicillin-resistant pneumococci have been identified should be
switched from Penicillin V to Amoxycillin before travelling and for one week after return.

36. Immunization
4. Asplenia in itself is not a contraindication to routine immunization. Normal inoculations, including live vaccines, can be given safely to adults with absent or dysfunctional spleens. 5. All splenectomised patients and those with functional hyposplenism should receive pneumococcal immunisation; Haemophilus influenzae type B [Hib] conjugate vaccine and conjugated meningococcal C vaccine [MenC] as soon as possible. For pneumococcal vaccination the 23-polyvalent pneumococcal vaccine [Pneumovax] should be used.

40. THANKS FOR YOUR ATTENTIONS