Spleen

detail of spleen

1. The Spleen
HANU PRATAP

2. Anatomy
of
Spleen

3. White Pulp

5. Spleen Structure
The white pulp is circular in
structure and is made up mainly
of lymphocytes. It functions in a
manner similar to the nodules of the
lymph node.
The red pulp surrounds the white
pulp and contains mainly red blood
cells and macrophages. The main
function of the red pulp is to
phagocytize old red blood cells.

6. Red Pulp

7. Function
The spleen is a sophisticated filter that monitors and manages
blood cells and immune functions
During fetal development the spleen produces red and white
blood cells
By the fifth month of gestation the spleen no longer has
hematopoietic function but retains the capacity throughout
life
Red cells that pass through the spleen undergo a “cleaning”
or repair
Abnormal and old cells are destroyed

8. Function
Reticulocytes loose their nuclear remnants and
excess membrane before entering the circulation
RBC’s coated with IgG and IgM are removed and
destroyed
◦The spleen is the site of destruction in autoimmune
disease states (ITTP and hemolytic anemia)
◦Parasites such as malaria can be removed as well
The spleen is involved in specific and nonspecific
immune responses (promotes phagocytosis and
destruction of bacteria)

9. Splenic Trauma
Diagnosis
◦Injury should be suspected in blunt upper abdominal injuries
( MVA and Bike)
◦Injuries are often associated with fractured ribs of the left
chest
◦Splenic injuries can cause extensive and continued
hemorrhage, others can cause subcapsular hematomas that
are subject to rupture at any time
◦If splenic injury is suspected, admission to the hospital for
monitoring is mandatory
◦The signs and symptoms of splenic trauma are those of
hemoperitoneum (generalized LUQ pain)

10. Treatment of Ruptured
Spleen
Splenic preservation operations
Partial splenectomy
Capsular repair
Non operative treatment

11. Delayed Rupture of the
Spleen
Injury to the pulp sometimes cannot be contained
indefinitely by the splenic capsule
The usual interval between injury and hemorrhage
is within two weeks (longer intervals have been
reported)
The incidence is between 15-30%
It is hoped that as imaging techniques improve the
incidence will decrease

12. Splenosis
Is the auto transplantation of splenic tissue after
splenic trauma
They vary from a few millimeters to several
centimeters in diameter
May occur anywhere in the peritoneal cavity
Seldom causes symptoms and is usually discovered
as an incidental finding at reoperation
Post splenectomy sepsis has renewed interest in
splenosis

13. Causes of splenomegaly
Infection
◦Bacterial: Typhoid fever, endocarditis, septicemia, abscess
◦Viral:E-B virus, CMV, and others
◦Protozoal: Malaria, toxoplasmosis
Hematologic processes
◦Hemolytic anemia: Congenital, acquired
◦Extramedullary hematopoiesis: thalassemia, osteopetrosis, myelofibrosis
Neoplasms
◦Malignant: Leukemia, lymphoma, histiocytoses, metastatic tumors
◦Benign: Hemagioma, hamartoma
Metabolic diseases
◦Lipidosis: Niemann-Pick, Gaucher disease
◦Mucopolysaccharidosis infiltration: Histiocytosis
Congestion
Cirrhosis
Cysts
Miscellaneous

14. Hypersplenism
Refers to a variety of ill effects resulting from
increased splenic function that may be improved
by splenectomy
The criteria for diagnosis included:
◦Anemia, leukopenia, thrombocytopenia or a combination
of the three
◦Compensatory bone marrow hyperplasia
◦Splenomegaly
Hypersplenism can be categorized as primary or
secondary

15. Splenic Involvement in
Hodgkin’s lymphoma
The probability of splenic involvement increases with
increasing spleen size
The absence of splenomegaly does not exclude splenic
involvement
Upon gross examination of the spleen a grayish white
nodule ranging from several millimeters to several
centimeters is apparent with Hodgkin’s disease
Liver involvement with Hodgkin’s disease rarely occurs
in the absence of splenic disease

16. Felty’s Syndrome
Is a syndrome consisting of severe rheumatoid
arthritis, granulocytopenia and splenomegaly
It usually occurs in patients with a long history of
rheumatoid arthritis
Severe, persistent and recurrent infections are
characteristic
Moderate splenomegaly is common
Splenectomy is effective in most patients

17. Gaucher’s Disease
Is a disorder of lipid metabolism that may result in
massive splenomegaly and hypersplenism
Commonly found in the Jewish population
Diagnosis is made by finding the typical Gaucher’s cells
in biopsy tissue
Massive splenomegaly is usually the most common
form of presentation
The adult form is the most common form
Splenomegaly (subtotal) shows great benefits

19. Cysts and Tumors of the
Spleen
The differential diagnosis of splenomegaly should
include splenic masses and primary tumors (these
conditions are rare however they must be
considered)
◦Cystic lesions comprise parasitic and nonparasitic cysts
◦Parasitic cysts are due almost exclusively to echinococcal disease
(rare in the United States)
◦Nonparasitic cysts are classified as primary (true) which have an
epithelial lining or pseudocysts (more common
◦Symptoms of splenic cysts are vague and are caused
primarily by mass effect (compression of adjacent
viscera)

20. Cysts and Tumors of the
Spleen
◦Selected nonparasitic cyst may be managed by aspiration
◦Splenectomy should be performed for all large cyst and those with an
uncertain diagnosis
◦Malignant and benign primary tumors of the spleen are rare
◦Most primary malignant tumors are angiosarcomas

21. Infectious Mononucleosis
A disease characterized by fever, sore throat,
lymphadenopathy and atypical lymphocytes
Most patients are young
Clinical symptoms are similar to those of a severe
upper respiratory tract infection
The spleen is enlarged and palpable in over 50% of
patients
Splenic rupture may occur

22. Incidental Splenectomy
The spleen is vulnerable to injury during operative procedures in the
upper abdomen
◦When the splenic capsule is torn, splenectomy is frequently performed
◦Morbidity and mortality is higher with iatrogenic injury requiring
splenectomy

23. Splenectomy
Prior to removing the spleen specific preoperative preparation is
necessary
◦All patients should receive polyvalent pneumococcal vaccine, polyvalent
meningococcal vaccine and Haemophilus influenzae type b conjugant
vaccine
◦Blood and blood products should be available well in advance of surgery

24. Postsplenectomy Sepsis
Asplenic patients have an increased susceptibility to
the development of overwhelming infection
The risk of sepsis is approximately 60 times greater
than normal after splenectomy
The risk is greatest in children younger than four years
of age
The risk of sepsis is higher among patients requiring
splenectomy for inherited diseases
The risk of sepsis after splenectomy is lowest after
trauma

25. Postsplenectomy Sepsis
The most common bacteria isolated our
streptococcus pneumoniae, Neisseria meningitidis,
E. coli or Haemophilus influenzae
Because half of the patients develop sepsis from
strep pneumoniae, penicillin can be administered
immediately with onset of a febrile URI
Patients are instructed to obtain and wear a Medic
alert tag

26. Hyposplenism
Is a potentially lethal syndrome characterized by diminished
splenic function
The patient peripheral blood smears appear as if they are
asplenic
Hyposplenism can occur in the presence of abnormal sized or
enlarged spleen
The danger of hyposplenism is the risk of developing potentially
lethal sepsis
Sickle cell anemia is the most common disease associated with
hyposplenism
The most common surgical disease associated with hyposplenism
is chronic UC

27. Hyposplenism

28. Overview
Definition of Hyposplenism
Medical History
The function of the spleen
Congenital asplenia vs. splenectomy
Immunological consequences of Hyposplenism
Diagnosis and complications

29. What is Hyposplenism?
Hyposplenism is the lack of a spleen or its function
The rare genetic disorder- Congenital Asplenia
The surgical removal of the spleen- splenectomy
Results in severe immunological consequences.

30. History
Immunological importance of the spleen
◦Morris and Bullock-1919
First post-splenectomy infection
◦O’Donnell-1929
Effects of Hyposplenism
◦King and Shumacker-1952

31. The Spleen
Largest lymphoid tissue of the body
Serves two main functions
◦Filters blood to remove damaged/old RBC- red pulp
◦Serves as secondary lymphoid tissue by removing infectious agents
and using them to activate lymphocytes- white pulp
A significant reservoir for T lymphocytes
Plays an active role in the production of IgM antibodies and
complement
Has significant role in the functional maturation of
antibodies

32. Congenital Asplenia
Autosomal recessive genetic disorder
Believed to be caused by absence of the Hox 11 gene in the embryo
Causes decreased adaptive immune response
Associated with structural abnormalities in other organs of the body-
cause death in infancy

33. Splenectomy
Removal of spleen tissue (partial or complete)
Usually needed because of trauma
Residual splenic function in ¼ to ⅔ of patients
IgM levels decreases, IgG levels remain constant or increase, IgA and
IgE levels increase

34. Immunological
Consequences
Causes slower and incomplete adaptive immune response
against bacteria
Low levels of tuftsin, which stimulates phagocytosis by
neutrophils, macrophages, and monocytes
Decreased neutrophil and macrophage activity
Increased NK cell activity
Limited capacity of circulating B-cells to differentiate into
antibody-secreting cells
Decreased level of T-cells

35. Diagnosis
Determined by anatomic presence or absence of
the organ, its size, and any lesions.
Function can be assessed by
◦Radiologic Techniques
◦X-ray, ultrasound, tomography, MRI, radionucleotide scanning
◦Morphologically
◦Peripheral blood smear- presence of Howell-Jolly bodies

36. Complications
Lifelong risk for Overwhelming Postsplenectomy infection
(OPSI)
◦Caused by Streptococcus pneumoniae and gram negative bacteria
◦Initial Symptoms: fever, chills, muscle aches, headache, vomiting,
diarrhea, and abdominal pain
◦Progressive symptoms: bacteremic septic shock, extremity gangrene,
convulsions, and coma
◦Mortality rate of 50-80%
◦from onset of initial symptoms, 68% of those deaths occur within 24 hours
and 80% occur within 48 hours
◦Prevention: routine vaccinations and prophylactic antibiotics

37. Summary
Hyposplenism is the lack of a spleen or its function
Can be either genetic or surgically induced
It has detrimental effects on the immune system by
decreasing the body’s ability to fight bacterial
infections and reducing the adaptive immune
response

38. Infections in
Asplenic
Patients

39. Causes of Asplenia
Congenital
◦Often associated with serious organ malformations
Acquired
◦Post surgical removal
◦Functional hyposplenism

40. Function of the Spleen
Immunological functions
◦Main site of opsonic antibody production
◦Especially efficient in removal of encapsulated bacteria
◦Remaining RES may compensate but not in case of encapsulated bacteria
Filtration
◦Removal of abnormal erythrocytes and intraerythrocytic inclusions eg nuclear inclusions and
parasitised RBC

41. Overwhelming Infection
Overall incidence of sepsis is low
◦3,2% in adults
◦3,3% in children
◦Risk stratified according to cause, being highest in patients with
thalassaemia major and sickle-cell anaemia (J Infect 2001 Oct;43: 182-6)
◦Lifetime risk for OPSI of 5%
Mortality
◦Death rates 600 times greater than general population
◦Higher in children (1,7% vs 1,3%), but other reports say higher in > 16
years
◦Mandel say doesn’t correspond to indication but Bisharat et al suggest
higher in haematological disorders

42. Duration of risk
Most occur within 2 years post splenectomy
Risk is lifelong as cases have been reported up to 20 years post surgery
Early complications may be underreported as surgical complication

43. Microbiology
S. pneumonia
◦50 – 90% of cases
◦Common in all age groups
◦Distribution of serotypes seems to be same as other forms of pneumococcal infection
◦75% belonged to serotypes covered in 23 valent vaccine (ibid)

44. Micro cont…
H. influenza
◦Regarded as 2
nd
most common cause
◦Incidence reduced with vaccination
◦Non-typable strains do not seem to predominate in PSS
N. meningitidis
◦Reported by some studies as associated but others as well as animal experiments seem to
support a lack of association

45. Other Micro-organisms
Listeria monocytogenes
E. coli
Klebsiella sp
Salmonella typhimurium
S. aureus
Cytocapnophagia canimorsus
Plesiomonas shigelloides
Recently occupational exposures have been
highlighted

46. Management
Immunisations
◦Pneumococcal – 2 weeks prior to elective surgery otherwise when patient is recovered prior to
discharge. Boosters every 5-10 years
◦H. influenza – recommended but evidence for immunogenicity and boosters lacking
◦Meningococcal – not routinely recommended
◦Influenza – may be of value especially in reducing risk of secondary bacterial infection

47. Mx continued…
Antibiotic prophylaxis
◦Controversial
◦Penicillin
◦In all cases, esp in first 2 years post surgery
◦All up to 16 and if underlying immune dysfunction
◦May not prevent sepsis
◦Local resistence patterns need to accounted for
◦Home antibiotic supply

48. Cont………
Travellers
◦MALARIA PROPHYLAXIS
◦Meningococcal vaccine
◦Antibiotic prophylaxis
Education
Medic alert bracelet etc.

49. THANK YOU