Spring 2024 ABD Spleen

• The spleen is the largest lymphoid organ
• Splenic artery supplies blood to the spleen, splenic vein drains it
• Average length

  12-13 cm
• Average AP

  <8 cm
• Average width

  4 cm
• In fetal life, the spleen is active in blood formation (hematopoiesis)
• In adults, the spleen plays more of a role in erythrocyte management
• Slightly mobile with respiration, though bound by several ligaments
• Intraperitoneal, ovoid organ covered by peritoneum (except at the hilum)
• Lies in the left hypochondrium with its axis along the 10th rib
• The inferior aspect extends toward midaxillary line
• Superior aspect is convex and inferior aspect is concave
• Splenic size varies based on the patient’s:

  • age (peds and geriatric smaller than adult)
  • gender (men larger than women)
  • nutritional status (larger in size during digestion and in the setting of an infection)
• Splenomegaly is when length >13 cm
• The spleen is a highly vascular organ, capable of storing more than 3L of blood
• The spleen consists of 2 types of tissues:

  Red pulp

  White pulp
• Ectopic spleen AKA

  wandering spleen

  splenoptosis
• ectopic spleen commonly results from splenoptosis caused by pregnancy or connective tissue disorders
• Accessory spleen AKA

  splenule

  supernummary spleen

  splenunculi
• accessory spleen are mostly located around the splenic hilum (75%) or pancreatic tail (20%)
• accessory spleen mostly measure about 2 cm
• polysplenia is rare, patients usually have bilateral left-sidedness
• the splenic parenchyma should have a fine, uniform, and homogeneous mid-to-low level echo patterns (similar to the liver)
• the echogenicity of the spleen is isoechoic to the liver
• as the spleen enlarges, the echogenicity increases and the echotexture becomes more coarse
• splenic vessels are concentrated at the hilum and quickly branch
• Difficult to differentiate between small arteries and veins without Doppler waveforms
• what are the 4 major functions of the spleen?

  defense

  hematopoiesis

  red blood cell and platelet destruction

  blood reservoir
• which spleen anomaly has a high and low torsion rate?

  high: ectopic spleen

  low: accessory spleen
• list 3 examples that could lead to abnormalities in the blood flow of the spleen?

  portal HTN

  splenic thrombosis

  splenic artery aneurysm
• The spleen is responsible for RBC production starting about 20-25 weeks GA
• With age, bone marrow assumes the primary function of RBC production
• The spleen retains is capacity to produce RBC throughout adult life, particularly in the setting of:

  Chronic anemia

  Bone marrow parenchyma loss
• what lab data indicates the percentage of RBCs per volume of blood?

  Hematocrit
• Abnormally low results of hematocrit indicates:

  hemorrhage

  anemia

  altered erythropoiesis

  leukemia
• what lab data indicates the presence of bacteria with the blood stream?

  bacteremia
• Sepsis is diagnosed when there is an abnormally large amount of bacteria in the blood stream. Can be fatal.
• what lab data indicates an abnormal increase in the number of WBCs in the blood stream?

  Leukocytosis
• what lab data is associated with infections, inflammation, hemorrhage, malignancies, and post-surgical status?

  leukocytosis
• what lab data indicates an abnormal decrease in the number of WBCs in the blood stream?

  Leukopenia