Transcript The Spleen
SPLENOMEGALY 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 ANATOMY OF SPLEEN ANATOMY OF SPLEEN 120mm SPLEEN STRUCTURE The white pulp is circular in structure and is made up mainly of lymphocytes. It functions in a way 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. FUNCTION During fetal development the spleen produces red and white blood cells Reticulocytes loose their nuclear remnants and excess membrane before entering the circulation RBCs or PLTs 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) SPLENOMEGALY 1. Palpable = significant, clear, usually clinically important. Usually after 1,5-2x increase in size. 2. Not palpable (Ultrasounf or CT diagnostics only) = not significant, usually clinically not important CAUSES OF SPLENOMEGALY Infection Bacterial: Typhoid fever, endocarditis, septicemia, abscess Viral:E-B virus, CMV, and others Protozoal: Malaria, toxoplasmosis Hematology benign disorders Hemolytic anemia: Congenital: her. Spherocytoisis etc., acquired : AIHA Extramedullary hematopoiesis: thalassemia, osteopetrosis, (myelofibrosis) Neoplasms Metabolic diseases Malignant haematology dioseases + other metastatic tumors Benign: Hemagioma, hamartoma Lipidosis: Niemann-Pick, Gaucher disease Mucopolysaccharidosis infiltration: Histiocytosis Congestion (eg right heart failure, thrombosis of v. lienalis) Cirrhosis Cysts + abscesses Miscellaneous CAUSES OF SPLENOMEGALY IN MALIGNANT HAEMATOLOGY 1. 2. 3. 4. 5. Myeloprolipherative diseases (MPD): - Primary myelofibroisis – PMF - Chronic myelogenous leukemia – CML - Polycythaemia vera – PV - Essential thrombocythaemia – ET Leukemia: Acute lymphoblastic leukemia, chronic lymphocytic leukemia (CLL), hairy cell leukemia (HCL), myelodysplastic syndromes (MDS) Lymphoma: Hodgfkin lymphoma, non-Hodgkin lymphoma Histiocytic diaseases Systemic mastocytosis 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 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 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 DIAGNOSIS OF SPLENOMEGALY Palpable vs non palpable US and/or CT scan (PET) Crucial point: cause of splenomegaly DIAGNOSIS OF SPLENOMEGALY Homogenous Palpable vs non palpable US and/or CT scan (PET) Focally non homogenous Crucial point: cause of splenomegaly DIAGNOSIS OF SPLENOMEGALY Homogenous Palpable vs non palpable US and/or CT scan (PET) Focally non homogenous Crucial point: cause of splenomegaly Not obvious Further investigation: Residual after sepsis? Primary splenic lymphoma? Abscesses? …… Gucher disease? Obvious: MPDs, NHL, HL, HCL, liver cirhosis, AIHA, h. spherocytosis, IM, malaria, etc. 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 Splenectomy (subtotal) shows great benefits SPLENECTOMY = Removal of the spleen Incidental versus Elective Main indications: Trauma Incidental Diagnostic splenectomy (ML – MZL, some PMF ) Therapeutic splenectomy: her. Spherocytosis, immune thrombocytopenia (ITP), etc. 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 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 HOWELL JOLLY BODIES Howell-Jolly bodies are round, purple staining nuclear fragments of DNA in the red blood cell COMPLICATIONS OF SPLENECTOMY Surgery related: relatively high morbidity and mortality associated in MPD (PMF). In other types of diseases low complication rate. Long life OPSI risk Earleir onset of atherosclerosis. POSTSPLENECTOMY SEPSIS (OPSI) Asplenic patients have an increased susceptibility to the development of overwhelming infection caused by encapsulated microorganisms. 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 The most common bacteria: Streptococcus pneumoniae, Neisseria meningitidis 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 POSTSPLENECTOMY SEPSIS The most common bacteria: Streptococcus pneumoniae, Neisseria meningitidis 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 All patients should be vaccinated Thank You very much