September 2, 2015 - The Spleen Flashcards
Red Pulp
Takes up ~75% of the volume of the spleen. It is here where macrophages destroy red blood cells and recycle iron.
White Pulp
It is here where the T cells interact with dendritic cells and circulating B cells.
Contains ~30% of the lympoid cells.
Size of a Normal Spleen
Is about the size of your fist.
Functions of the Spleen
- Removal of aged or abnormal blood cells
- Immune function (particularly against encapsulated organisms)
- Hematopoiesis in the fetus (and sometimes in adults)
- Reserve pool and storage site
- Recycling of iron
Howell-Jolly Bodies
Contain nuclear remnants. Their presence indicates a damaged or absent spleen.
Heinz Bodies
Contain denatured hemoglobin and are only visible with a special stain.
Can indicate G6PD deficiency, alpha-thalassemia, or hypospenism.
Common Enscapsulated Bacteria
Important to vaccinate against these before the removal of the spleen.
- Streptococcus pneumoniae*
- Hemophilus influenzae B*
- Neisseria meningitidis*
Spleen and Hematopoiesis
Normally only functions as a hematopoietic organ during the 2nd trimester of a fetus, however it can also act in this way in hemolytic anemia that is chronic. (eg. Thalassemia or bone marrow disease)
Symptoms of Splenomegaly
- Usually none unless very large
- Pain or discomfort in LUQ
- Early satiety due to compression of stomach
- Pain referred to left shoulder
Castell’s Sign
Last intercostal space on the left side.
Normally is resonant on inspiration and expiration.
In splenomegaly, is dull or becomes dull on inspiration.
Splenomegaly Causes
- Congestive
- Infiltrative
- Infectious
- Inflammatory
- Hemolytic Disease
Congestive Splenomegaly
Engorgement and congestion in red pulp with increased vascularity and increased pooling.
Caused by portal hypertension. This can be due to cirrhosis, or non-cirrhotic PHTN.
Hemolytic Disease and Splenomegaly
Increased macrophage function due to phagocytosis of abnormal cells.
Increased blood pooling.
Extramedullary hematopoiesis.
Infection and Splenomegaly
Can be caused by many things, but in our society, the most common are viruses. Particularly EBV.
Inflammatory Splenomegaly
Can be caused by many conditions. It is important to look for inflammatory markers and antibodies.