TCM Spleen Disease Spleen Physiology Spleen Pathology Cases.
The Spleen. Anatomy of Spleen White Pulp Spleen Structure The white pulp is circular in structure...
Transcript of The Spleen. Anatomy of Spleen White Pulp Spleen Structure The white pulp is circular in structure...
The Spleen
Anatomy of Spleen
White Pulp
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.
Red Pulp
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
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)
Sites of Haemopoiesis Yolk sac
Liver and spleen
Bone marrow Gradual replacement of
active (red) marrow by tissue inactive (fatty)
Expansion can occur during increased need for cell production
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)
Treatment of Ruptured SpleenSplenic preservation operationsPartial splenectomyCapsular repairNon operative treatment
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
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
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
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
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
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
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
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)
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
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
Incidental SplenectomyThe 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
SplenectomyPrior 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
Blood Compositional Changes in the Asplenic or Hyposplenic Patient The absence of functional splenic tissue results
in characteristic changes in the circulating blood Some of these are predictable and desirable results These changes are considered a measure of its
success when splenectomy is performed for a hematologic disease
Howell-Jolly bodies (nuclear remnants) and thrombocytosis (desired result)
Other findings include: target cells, acanthocytes (spur cells), Heinz bodies (denatured hemoglobin) and stippled red cells
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
Postsplenectomy Sepsis Postsplenectomy sepsis syndrome typically
occurs in a previously healthy individual after a mild upper respiratory tract infection associated with fever
Within hours, nausea, vomiting, headache, confusion, shock and coma can occur; death follows within 24 hours
The nature of the syndrome makes it difficult to diagnose early enough for therapy to be effective
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
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
Hyposplenism
OverviewDefinition of HyposplenismMedical HistoryThe function of the spleenCongenital asplenia vs. splenectomy Immunological consequences of
HyposplenismDiagnosis and complications
What is Hyposplenism?Hyposplenism is the lack of a spleen or
its functionThe rare genetic disorder- Congenital
AspleniaThe surgical removal of the spleen-
splenectomyResults in severe immunological
consequences.
History Immunological importance of the spleen
Morris and Bullock-1919First post-splenectomy infection
O’Donnell-1929Effects of Hyposplenism
King and Shumacker-1952
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
Congenital AspleniaAutosomal recessive genetic disorderBelieved to be caused by absence of
the Hox 11 gene in the embryoCauses decreased adaptive immune
responseAssociated with structural abnormalities
in other organs of the body- cause death in infancy
SplenectomyRemoval of spleen tissue (partial or
complete)Usually needed because of traumaResidual splenic function in ¼ to ⅔ of
patients IgM levels decreases, IgG levels remain
constant or increase, IgA and IgE levels increase
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
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
Howell Jolly bodies
Howell-Jolly
bodies are round,
purple staining nuclear
fragments of DNA in the red
blood cell
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
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
Infections in Asplenic Patients
Causes of AspleniaCongenital
Often associated with serious organ malformations
Acquired Post surgical removal Functional hyposplenism
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
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
Duration of riskMost occur within 2 years post
splenectomyRisk is lifelong as cases have been
reported up to 20 years post surgeryEarly complications may be
underreported as surgical complication
MicrobiologyS. 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)
Micro cont…H. influenza
Regarded as 2nd 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
Other Micro-organisms Listeria monocytogenes E. coli Klebsiella sp Salmonella typhimurium S. aureus Cytocapnophagia canimorsus Plesiomonas shigelloides Recently occupational exposures have been
highlighted
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
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
Cont………Travellers
MALARIA PROPHYLAXIS Meningococcal vaccine Antibiotic prophylaxis
EducationMedic alert bracelet etc.