Spleen & Lymphatic System
What is autosplenectomy?
An almost complete disappearance of the spleen through progressive fibrosis and shrinkage (ie. sickle cell anemia)
What is leukopenia associated with?
Aplastic anemia*, viral infections (AIDS), late stages of leukemia, and diabetes
What is another name for Acquired Hypoplasia?
Functional Aplasia
What is the most common benign primary neoplasm of the spleen?
Hemangioma
What is the term for decreased white blood cell count?
Leukopenia
What is the most common splenic malignancy?
Lymphoma
What is another name for a hamartoma?
Splenoma / Atypical hemangioma
What is the term for increased RBC?
polycythemia
What is the sonographic appearance of a splenic abscess?
- Complex cystic mass with irregular borders - Some solid components - * Dirty shadowing because of gas - possible pleural effusion
What are the reasons for congestive splenomegaly?
- Heart failure - Cirrhosis - Portal hypertension - Portal/Splenic vein thrombosis - Cystic fibrosis
What are the categories of splenic hematomas?
- Perisplenic - Intraperitoneal - Subcapsular - Intraparenchymal
What are the causes of a splenic hematoma?
- rupture of hemangioma - rupture of a neoplasm - rupture of an aneurysm - secondary to interventional complications - blunt abdominal trauma
What is the sono appearance of echinococcal cysts?
-cyst within a cyst -daughter cysts can attach via a stalk or as an outpouching of the main cyst -may have hydatid sand -Final stage: granuloma
What is the typical measurement of an accessory spleen?
1-3 cm, but can reach 5 cm if accompanied by splenic enlargement
What are the functions of the spleen?
1. Acts as a filter and reservoir for blood 2. Breakdown of Hemoglobin 3. Formation of bile pigment 4. Formation of antibodies
What is a pseudocyst?
A collection of fluid without an epithelial lining
What is Acquired Hypoplasia?
A non-congenital disorder where the spleen becomes small and non-functioning due to a chronic condition such as sickle cell anemia, thyrotoxicosis, and celiac disease.
What is massive splenomegaly and what causes it?
A spleen is considered to have massive splenomegaly when its length exceeds 18 cm. It can be caused by leukemia, lymphoma, primary neoplasm, or malaria.
What is the classic sonographic appearance of a splenic infarction?
A wedge-shaped hypoechoic area with the widest portion continuous with the capsule
What is the most common variant of the spleen?
Accessory spleen (supernumerary spleen, spleniculi)
What does the splenic vein bring to the liver?
Blood rich in unconjugated bilirubin
What is Polycythemia Vera?
Bone marrow hyperplasia producing RBCs at a rate too fast for the spleen to handle
If an accessory spleen is not removed during a splenectomy, it may enlarge after. What is this called?
Born Again spleen
What is the sonographic appearance of splenomegaly?
Depends on cause - if congestive - hypoechoic - if chronic - hyperechoic
Splenomegaly can be caused by all of the following except: A. Infection B. METS C. Trauma D. Hemolytic Anemia E. All of these conditions are causes of splenomegaly.
E. All of these conditions are causes of splenomegaly.
Name two types of true cysts of the spleen.
Epidermoid cysts Adult Polycystic Kidney Disease (affects kidneys, liver, spleen, & pancreas and are usually multiple in number)
True/False The spleen should appear heterogeneous because of the red and white pulp.
False. The spleen should appear homogeneous with mid-level echoes. It should be isoechoic or slightly less echogenic than the liver.
True/False The normal spleen is isoechoic to slightly hyperechoic to the normal liver.
False. The spleen is isoechoic to slightly hypoechoic to the normal liver.
True/False In cases where the spleen has an abscess, it is often the only site of infection.
False. 80% of the cases of splenic abscesses are associated with general sepsis.
True/False Ultrasound is the imaging modality of choice when scanning the spleen for trauma.
False. CT is the imaging modality of choice.
True/False True cysts are the most common type of splenic cyst and are congenital.
False. True cysts of the spleen are congenital, but they are rare.
Where does erythropoiesis take place in adults? Where does it take place in the fetus?
In bone marrow in adults In the liver and spleen in the fetus
What is asplenia and what is it associated with?
It is a congenital absence of the spleen. It is associated with congenital heart defects, situs inversus, and "Bilateral Right-Sidedness Syndrome."
What is the function of the red pulp?
It is the venous component of the spleen which filters the blood and is important in the breakdown of RBCs. A byproduct of this process is unconjugated (indirect) bilirubin which is then transported to the liver to be conjugated and used in the production of bile.
Where is the spleen located?
LUQ between the left hemidiaphragm and the stomach
What structures/organs border the spleen?
Left hemidiaphragm, stomach, pancreatic tail, left kidney, and splenic flexure of the colon.
What is the term for an increased white blood cell count?
Leukocytosis
What is polysplenia and what is it associated with?
Multiple spleens (typically 2 large with a bunch of smaller ones). It is associated with Bilateral Left-Sidedness Syndrome.
Which organs below are retroperitoneal? Liver, Pancreas, Stomach, Kidney, Spleen
Pancreas and Kidney
What is the most common type of splenic cyst?
Parasitic (specifically, echinococcal cyst)
What is the most common cause of splenomegaly in adults?
Portal hypertension
What is the function of the white pulp?
Production of lymphocytes and plasma cells which are important for the formation of antibodies
What are the symptoms of echinococcal cyst?
RUQ pain (because the parasite typically travels to the liver) Hepatosplenomegaly Slight increase in ALP
What are the main components of the splenic parenchyma.
Red and White Pulp
What is Erythropoiesis?
The formation of red blood cells
To which system does the spleen belong?
The immune system/ lymphatic system
What is Situs Solitus?
The normal arrangement of visceral organs
True/False The spleen can be the only site of infection.
True. The spleen may be the only site of infection in immunocompromised patients (AIDS) or if the spleen has been injured.
A spleen that is malpositioned and may move around within the abdominal cavity is termed this.
Wandering (Floating, Aberrant) Spleen
What is the term for decreased RBC?
anemia; pancytopenia
What is the normal length of the spleen?
approximately 12-14 cm
What is the white pulp in the spleen and what percentage of the spleen is white pulp?
lymphatic tissue (mostly lymphocytes) the spleen is 15% white pulp.
What is the sonographic appearance of an accessory spleen?
small (1-3 cm), round, homogenous nodules isoechoic to the spleen with the same characteristic color flow (low resistance)