Fiser Chapter 34 SPLEEN

Question 1

Splenic arteries

Answer 1

Splenic and short gastrics (end arteries), left gastroepiploic

Question 2

Splenic vein location

Answer 2

Posterior and inferior to splenic artery

Goes into portal vein

Question 3

Speen function

Answer 3

Reservoir for platelets

Ag-processing center for macrophages

Largest producer of IgM

Red pulp (85%): filter for aged or damaged RBCs

White pulp (15%): immunologic, contains lymphocytes and macrophages

Hematopoiesis before birth and in myeloid dysplasia

Question 4

Red pulp

Answer 4

filter for aged or damaged RBCs

Pitting: removal of abnormalities in RBC membrane
Howell-Jolly bodies- nuclear remnants
Heinz bodies- hemoglobin

Culling: removal of less deformable RBCs

Question 5

White pulp

Answer 5

Immunologic function; contains lymphocytes and macrophages

Major site of bacterial clearance that lacks preexisting Abs

Site of removal of poorly opsonized bacteria, particles, debris

Ag processing occurs with interaction between macrophages and helper T cells

Question 6

Tuftsin

Answer 6

An opsonin that facilitates phagocytosis and is produced in spleen

Question 7

Properdin

Answer 7

Activates alternate complement pathway, produced in spleen

Question 8

Accessory spleen most commonly found where

Answer 8

Splenic hilum

Occurs in 20%

Question 9

Splenectomy indications

Answer 9

Trauma
ITP >> TTP
Hypersplenism
Hereditary spherocytosis
Pyruvate kinase deficiency
G6PD deficiency (sometimes)
Beta thalassemia (if splenomegaly)
Warm antibody-type acquired immune hemolytic anemia
Lymphomas
Splenic sarcoidosis
Felty's syndrome
Splenectomy
Splenic cysts

Question 10

ITP pathophysiology

Answer 10

Anti-platelet IgG binds platelets

Petechiae, gingival bleeding, bruising, soft tissue ecchymosis

Normal spleen

Tx: steroids, gammaglobulin if steroid resistant, splenectomy for those who fail steroids

Question 11

How does splenectomy help ITP?

Answer 11

Removes IgG production and source of phagocytosis

Give platelets 1 hour before surgery

80% response; Avoid splenectomy in children < 10 years, will usually resolve spontaneously; At least wait until 5 so they have Ab’s

Question 12

TTP pathophysiology

Answer 12

Loss of platelet inhibition leads to thrombosis and infarction -> profound thrombocytopenia

Purpura, fever, AMS, renal dysfunction, hematuria, hemolytic anemia

Tx: Plasmapheresis; immunosuppression; 80% respond to medical tx; splenectomy RARELY indicated

Death from intracerebral hemorrhage or ARF

Question 13

Risk of post-splenectomy sepsis syndrome

Answer 13

Most episodes occur within 2 years after splenectomy
0.1%
Children have higher risk and mortality
Higher in hemolytic disorders or malignancy

Question 14

Post-splenectomy sepsis syndrome bacteria

Answer 14

SHiN: S pneumonia, H influenza, N meningitides

Question 15

Post-splenectomy sepsis syndrome pathophysiology

Answer 15

Lack of IgM to capsulated bacteria

Question 16

Vaccines needed before splenectomy

Answer 16

Pneumococcus
Meningococcus
H influenza

Question 17

Hypersplenism definition

Answer 17

-Decreased circulating cell count of erythrocytes and/or platelets and/or leukocytes
-Normal compensatory hematopoietic response in BM
-Correction of cytopenia by splenectomy
+/- Splenomegaly

Question 18

Spherocytosis

Answer 18

• Most common congenital hemolytic anemia requiring splenectomy
• Spectrin deficit (membrane protein) deforms RBCs and leads to splenic sequestration (hypersplenism)
• Causes pigmented stones, anemia, reticulocytosis, jaundice, splenomegaly
• Tx: Splenectomy and Cholecystectomy; curative

Question 19

Elliptocytosis

Answer 19

Similar to but less common that spherocytosis

-Spectrin and protein 4.1 deficit (membrane protein)

Question 20

Pyruvate kinase deficiency

Answer 20

Altered glucose metabolism

• -> congenital hemolytic anemia
• -> RBC survival enhanced by splenectomy

Most common congenital hemolytic anemia NOT involving membrane protein that requires splenectomy

Question 21

G6PD deficiency

Answer 21

Splenectomy usually not required

Question 22

Causes of spontaneous splenic rupture

Answer 22

Mononucleosis
Malaria
Sepsis
Sarcoid
Leukemia
Polycythemia vera

Question 23

What is splenosis

Answer 23

Splenic implants

Usually related to trauma

Question 24

Results of splenectomy/hyposplenism

Answer 24

Howell-Jolly bodies (nuclear fragments)
Heinz bodies (Hgb deposits)
Pappenheimer bodies (iron deposits)
Target cells
Spur cells (acanthocytes)
Transient thrombocytosis
Transient leukocytosis
Persistent lymphocytosis
Persistent monocytosis

Question 25

Most common cause of splenic artery or splenic vein thrombosis?

Answer 25

Pancreatitis

Question 26

Postsplenectomy changes in blood

Answer 26

Increased RBCs
Increased WBCs
Increased platelets: if > 1 x 10^6, give ASA

Question 27

Most common splenic tumors

Answer 27

Benign: Hemangioma (most common overall)
Malignant: Non-Hodgkin’s lymphoma

Question 28

Guidelines for prevention of ppostplenic sepsis

Answer 28

• If possible vaccinate with polyvalent pneumococcal vaccine at least 10-14 days prior to splenectomy
• If urgent, wait at least 14 days postop to vaccinate
• Also meningococcal and H influenza vaccine for high-risk patients (immunosuppressed of children <10yo)
• Abx ppx for children <5yo
• Early Abx for initial signs of infection
• MedicAlert bracelet