spleen

SPLEEN

Dr. Hamid Hindi


I. Anatomy- weight – approximately 100-150 grams- located in the left upper and protected by the lower portion of the rib cage- its position is maintained by several ligamentsa. splenophrenicb. splenorenalc. splenocolicd. gastrosplenic – short gastric a.

Spleen

- it is supplied by the splenic artery, which is a branch of the coeliac artery. - accessory spleens have been reported in 14% to 30%, ususally seen at the hilum, greater omentum, and ligaments of the spleen

Blood supply

- consists of the capsule and trabeculae which enclose the pulp.- 3 zones of the pulpa. White pulp – lymph node; contains lymphocytes, macrophages, and plasma cells in a reticular networkb. Red pulp – consists of the cord and sinuses; contains the cellular elements of the blood c. Marginal zone – poorly defined vascular space between pulps; contains sequestered foreign material and plasma as well as abnormal cellular elements

histology

II. Physiologic FunctionsA. Filtering – splenic blood flow – 350 ml/day1. removal of abnormal red blood cells – approximately 20 ml of aged RBC are removed daily2.removal of abnormal WBC, plateletes


B. Immunologic Function1. opsonin production2. antibody synthesis (IgM)3. protection from infectionC. Storage Function1. plateletes – 1/3 are stored in the spleen 2. in splenomegaly, up to 80% of the plateletes may be stored in the spleen  thrombocytopenia

splenomegally

splenomegally


III. Diagnostic A. Evaluation of size 1. physical examination a. not normally palpable b. felt in 2% of healthy adults c. no significant dullness elicited by percussion over spleen d. as organ enlarges, dullness is detected at the level of the 9th ICS in the left anterior axillary line

2. CT/MRI – depicts the spleen and defines abnormalities in size, shape and parenchymal pathology3. 99 Tc colloidB. Evaluation of function1. hypersplenism – reduction in number of RBC, WBC, plateletes2. increase in cellular destruction results in compensatory rise in production in the bone marrow  reticulocytosis

IV. PathologiesA. Rupture of the Spleen1. Etiology – disruption of the spleen’s parenchyma, capsule, and blood supplya. spleen is the most commonly injured organ following blunt traumab. 2% splenic injury during surgery in the LUQ – Gastric surgeryc. spontneous rupture – hematologic disorders

CT scan of splenic and liver trauma

2. Pathology a. splenic rupture i. intraperitoneal bleed ii. 90% of blunt trauma b. delayed rupture i. interval of days or weeks between injury and bleeding; 10%-15%

ii. Quiescent period (of Baudette) persists for less than 7 days up to 2 weeks iii. related to temporary tamponade of minor lacerations or slowly enlarging subcapsular hematoma


c. occult splenic rupture- pseudocyst of the spleen (1%)3. Clinical manifestationa. hypovolemia/tchycardiab. hypotensionc. localized (LUQ) or generalized abdominal paind. Kehr’s sign – pain at the tip of the left shoulder  diaphragmatic irritatione. Balance’s sign ( mass or fixed dullness at the left upper quadrant

4. diagnostic studiesa. CBC – serial Hct determination leukocytosisb. x-ray of the abdomeni. fractured ribsii. elevated immobile diaphragmiii. enlarged splenic shadowiv. medial displacement of gastric shadow v. widening shadow between splenic flexure and preperitoneal fat

c. CT scand. angiography5. Treatment – surgerya. children – delayed surgical managementb. adult - splenectomyc. splenectomized patients should receive pneumovax Haemophilus influenza vaccine and children should also be given oral penicillin daily until age 18

B. Hypersplenism 1. Primary hyperslenism a. diagnosis by exclusion made after secondary hypersplenism has been excluded b. rare entity affecting women c. anyone or all formed elements may be affected d. enlarged spleen e. recurring fever and infection f. lymphoma and leukemia g. responds to splenectomy h. steroids do not improve condition

2. Secondary hypersplenism – caused by an identifiable underlying disease a. portal hypertensioni. splenic congestionii. most common cause of secondary hypersplenismiii. does not warrant splenectomy

b. splenic vein thrombosis i. massive splenomegaly ii. thrombosis secondary to pancreatitis iii. associated with bleeding esophageal varices iv. cured by splenectomy

CT and Angiogram of splenic vein thrombosis

c. other causesi. neoplasms – leukemia, lymphoma, metastatic carcinomaii. myelproliferative disordersiii. increase in RBC destruction – thalassemia majoriv. disorders in immune response – infectious mononucleosis, Felty’s syndrome (rheumatoid arthritis, splenomegally, neutropenia)v. diseases that infiltrate the spleen – amyloidosis, sarcoidosis

Splenic tumor

V. SplenectomyA. Absolute Indications for Splenectomy1. splenic tumors – echinoccocal cyst2. metastatic disease3. splenic abscess4.hereditary spherocytosis – most common hemolytic anemia for which splenectomy is indicated5. bleeding esophageal varices


CT scan of splenic abscess


6. chronic lymphocytic leukemia7. hairy cell leukemia8. Chronic myeloid leukemia – more to ease the pain9. Sarcomas10 trauma

B. Relative indications for splenectomy 1. congenital hemolytic anemias 2. sickle cell anemia 3. idiopathic autoimmune hemolytic anemia 4. Thrombocytic thrombocytopenic purpura


5. Felty’s syndrome/Sarcoidosis (non-caseating granulomas)/Gaucher’s disease (lipid storage disease)/Niemann-Pick disease (abnormal storage of cholesterol and sphingomyelin)/Amyloidosis (abnormal extracellular storage of protein)6. Chronic rheumatoid arthritis7. granulocytopenia8. Hodgkin’s lymphoma9. Non-hodgekin’s lymphoma10. idiopathic thrombocytopenic purpura

VI. Splenectomy Outcomes - post-operative appearance of: a. siderocytes b. Howell-Jolly bodies c. leukocytosis d. increased platelete count

A. Complications1. left lower lobe atelectasis – most common2. subphrenic hematoma3. subphrenic abscess – can occur with placement of a drain4. pancreatitis – trauma to the tail of the pancreas5. deep vein thrombosis – low dose anticoagulants

B. Hematologic outcomes1. initiala. thrombocytopenia – rise in platelete count within a few daysb. chronic hemolytic anemias – Hgb level above 10 g/dl

2. long-terma. increase in platelete count– rise to >150,000 more than 2 months after surgeryb. 90-100% success for hereditary spherocytosis

C. Overwhelming Post-Splenectomy Infection (OPSI) 1. lifetime risk of severe infection2. incidence of 3.2% post-splenectomy3. loss of the spleen’s ability to filter and phagocytose bacteria and infected RBC

4. most common sources of infectiona. Streptococcus pneumoniae – most commonb. Heamophilus influenzae Bc. meninggococcusd. group A streptococci5. presents with pneumonia or meningitis


6. risk factors for the development of OPSIa. indication for splenectomy - hematologic disorder vs traumab. overall immune statusc. interval from the date of surgery – usually within 2 years

7. prevention a.vaccine against i. pneumoccocus ii. H. influenzae iii. meninggococcus - to be given within 7-14 days after splenectomy


b. booster dose for pneumococcal vaccine every 5-6 years c. annual influenza vaccine d. daily dose of penicillin or amoxycillin for 2 years