Spleen

Anatomy» Surface Relations

˃ Stomach˃ Renal˃ Colon

» Suspended by˃ Phrenosplenic ligament˃ Gastrosplenic ligament˃ Splenocolic ligament˃ Gastrocolic ligament

» Blood Supply˃ Splenic artery, L

gastroepiploic, short gastrics˃ Splenic Vein

Histology

» Two general components:˃ White pulp (5-20%)˃ Red pulp (~85%)˃ Enclosed by capsule and interspersed with trabeculae

Physiology-for the residents!» Filtration

˃ Stiff or fragile RBCs cannot pass through interendothelial slits

» Immune function˃ Splenic phagocytes, together with

macrophages in the liver,synthesize the majority of components of the classical pathway of complement

˃ Slow blood flow in the red pulp cords allows foreign particles to be phagocytosed without specific ligand-receptor interactions

˃ Important in fighting early bacterial infection

Physiology-function of spleen

Non-traumatic indications for splenectomy

Splenectomy for platelet disorders» Idiopathic thrombocytopenic purpura

˃ Most common hematologic indication for splenectomy

˃ Spleen is the source of circulating antiplatelet IgG

˃ Also responsible for sequestration of sensitized platelets

˃ Dx made by thrombocytopenia with normal bone marrow

˃ Patients present with ecchymosis and purpura and at times there is excessive bleeding from the gums, vaginal bleeding, gastrointestinal bleeding, and hematuria

˃ Platelet count characteristically less than 50,000/mm3

Splenectomy for platelet disorders» Idiopathic thrombocytopenic purpura

˃ First line of treatment medical+ Steroids+ IgG+ Plasmapheresis

» Medical treatment only curative in 15% of adults

» Cure rates up to 87% reported with splenectomy

» Given risks of splenectomy, should be reserved for patients with platelet counts <25,000/mm3 and bleeding

Splenectomy for platelet disorders

» Thrombotic Thrombocytopenic Purpura˃ Increase of subendothelial collagen in the arterioles and capillaries

causing diffuse platelet trapping ˃ Manifested by thrombocytopenia, hemolytic anemia, fever, neurologic

manifestations, and renal disease˃ Primarily treated with high volume plasmapheresis (80 to 90%

survival)˃ Steroids and ASA˃ Splenectomy reserved for non-responders

Splenectomy for hematologic malignancy» Hodgkin’s Disease

˃ Historically, staging laparotomy with splenectomy were essential guides to treatment

˃ Improvement in imaging and chemotherapy have minimized the role of the surgeon

» Splenectomy for non-Hodgkin’s lymphomas˃ Symptomatic splenomegaly˃ NHL confined to the spleen or with

prominent splenic involvement (survival improvement from 24 to 108 months)

» Leukemias˃ Splenectomy indicated for symtpomatic

splenomegaly

Splenectomy for hemolytic disease» Hereditary Spherocytosis

˃ Autosomal dominant trait˃ Most common hemolytic anemia for

which splenectomy is advised ˃ Defective erythrocyte membrane causes

trapping and disintegration within the spleen

˃ Presents with anemia, reticulocytosis, jaundice, and splenomegaly

˃ Diagnosis made by peripheral blood smear

˃ Splenectomy is the only therapeutic modality (wait until age 4 to 6)

˃ Outcomes are excellent

Splenectomy for hemolytic disease» Thalasemia

˃ Autosomal dominant transmission˃ Defect in the synthesis rate of hemoglobin˃ Thalassemia major (homozygous) presents with

pallor, retarded body growth, enlarged head, and intractable ulcers

˃ Diagnosis made by nucleated RBCs (target cells) in smear

˃ Splenectomy reserved for patients with markedly symptomatic splenomegaly, painful splenic infarction, and increased transfusion requirement

˃ Greater risk of post-splenectomy sepsis

Splenectomy for hemolytic disease

» Sickle Cell Disease˃ Spleen commonly enlarged during the first decade of life but then

undergoes progressive atrophy due to repeated attacks of vaso-occlusion and infarction

˃ In general, splenectomy should be avoided in patients with SCD (immunocompromized)

Splenectomy for hemolytic disease

» Sickle Cell Disease˃ Main indications are:

+ Acute splenic sequestration crisis– Circulatory collapse and sudden death from the rapid

sequestration of red blood cells– Second-leading cause of pediatric deaths in patients with

SCD+ Hypersplenism

– Splenectomy decreases transfusion requirements– Partial splenectomy may be an option2

+ Splenic abscess– Increased incidence of Salmonella

With regards to splenic anatomy which of the following statements is/are true?» The embryologic origin is in the ventral

mesogastrium» The suspensory ligaments with the exception of the

gastrosplenic ligament are avascular» The spleen is fixed in the LUQ and cannot be safely

mobilized» Accessory spleens are most commonly located along

the greater omentum

What are the organisms that an individual must be vaccinated against to protect against OPSS?» H. Influenzae» Strep Pneumoniae» N. Meningetidis

Which of the following is/are true regarding the microanatomy of the spleen?» White pulp serves a phagocytic function

» Red pulp serves an immunologic function

» Microcirculation is predominantly a closed system with direct AV channels

» Cellular elements of the blood pass directly from red pulp cords to sinuses

Which of the statement regarding the spleen is/are true?

» The spleen can only remove cells coated with IgA

» Levels of properdin and tuftsin fall after splenectomy

» Lack of howell-jolly bodies after splenectomy suggests the presence of accessory spleens

» Encapsulated bacteria are effectively removed in asplenic individuals

» Is a site of hematopoiesis throughout life

Regarding the management of ITP which of the following is/are true?

» Splenectomy is indicated for patients who fail to improve with initial therapy with steroids

» Splenectomy is more often necessary in children with ITP than it is for adults

» Splenectomy is not indicated in the absence of splenomegaly

» Preoperative platelet transfusions are recommended for patients with platelets under 50K

» The sole reason for splenectomy in ITP is to remove the source for platelet phagocytization

The primary pathophysiology of TTP involves which one of the following?» Circulating antiplatelet antibodies

» Venous thrombosis

» Arteriolar and capillary occlusion

» Intravascular activation of the coagulation cascade

Regarding staging laparotomy of patients with Hodgkin’s disease, which of the following statements is/are ture?» Lymphangiography and CT used together have eliminated the

need for staging laparotomy

» The operative technique of a staging laparotomy is different for women than men

» Partial splenectomy is adequate for staging and has helped lower OPSS

» Staging laparotomy results is a change in the stage of Hodgkin’s disease in 40% of cases

In which of the following disorders does splenectomy clearly influence survival?» CLL

» CML

» Non-Hodgkin’s lymphoma

» Hairy cell leukemia

» Myeloid metaplasia

Regarding Postsplenectomy sepsis, which of the following statements is/are true?» It is the most common complication of splenectomy for

hematologic disease» The onset is typically characterized by sudden high

fevers» It is more common in adults than in children» It is more commonly fatal in children than adults» It is more common after splenectomy for hematologic

disease than for trauma