Spleen Flashcards
The spleen is _____ organ located in the ___ _____ quadrant between the _____ and ______.
peritoneal
left upper
stomach and diaphragm
Basic function of the spleen.
remove blood cells from circulation
- largest lymphoid organ, filters damaged cells, mircorganisims, and particulate matter
- and delivers antigens to the immune system
What designates splenomegaly
> 12-13cm sup/inf diameter
if spleen is inferior to the lower pole of the LT kidney
In the case of hepatomegaly or pregnancy what might be visualized?
left lobe may extend anterior to the spleen
What is located on the visceral/medial surface of the spleen?
STO
Left kidney
pancreas
splenic flexure of the colon
The fundus of the ____, lesser sac and pancreatic ____ are medial and _____ to the splenic hilum.
stomach
tail
anterior
The tail of the pancreas is located ____ to the stomach and lesser sac as it approaches the splenic hilum.
posterior
The left kidney lies _____ and _____ to the spleen.
inferior and medial
The pancreatic tail is located ____ to the upper pole of the left kidney in the splenic hilum.
anterior (ventral)
T/F - splenic artery should be tortuous
T
Accessory spleen
aka splenunculi, is normal congenital ectopic splenic tissue
What could be confused with a splenunculi?
enlarged lymphnodes around the spleen or a mass in the tail of the pancreas
Accessory spleens are small rounded masses, less than ____cm in diameter and located near the ____ ____.
5cm
splenic hilum
Granulomas
splenic calcifications, focal lesions resulting from prevous infection
-also found in the liver and lungs
Most comon cause of granulomas
histoplasmosis
TB
Sono appearance of granulomas
focal bright echogenic lesions, with or without shadowing
Splenic calcs can be associated with:
splenic artery wall calc
splenic artery aneurysms calcs
oneumocystis carini infection
splenic infarcts
What cystic lesions may be found in the spleen:
ADPKD
hydatid - usually liver
epidermoid cysts (true cysts lined with squamous epithelium)
Liquified infarcts or hematomas
Pancreatic Pseudocysts (can erode into the spleen and weaken vessels, causing PAs and bleeding into the pseudocyst)
Sonographic findings of a splenic epidermoid cyst
typically solitary
10cm
may be calcified and the internal contents appera echogenic
Most common benign primary neoplasm of the spleen?
hemangiomas
-primary neoplasms are rare
METS to the spleen are _____. What 3 primaries in order?
uncommon
malignant melanoma, breast, lung
Appearance of METS to the spleen
commonly hypoechoic but varies
What kind of patients do splenic infarcts occur in?
common in patients with endocarditis and splenic artery aneurysms
Sonographic appearance of splenic infarcts
generally present as a peripheral wedge-shaped hypoechoic lesion
it changes with the stages of blood coagulation….
-Initially, ischemia and edema appear as hypoechoic wedge of tissue
-With necrosis and liquification the area will appear anechoic and ultimately will calcify
What are splenic abscesses the result of?
sepsis due to endocarditis,
dental infections,
urosepsis
Sonographic appearance of splenic abscesses
complex cystic lesions
presence of gas may produce echogenic foci with an associated reverberation (comet-tail) artifact
Sickle cell disease is due to a mutant hemoglobin S resulting in sickling of RBCs and teh complications of this include (7)
anemia - dec RBCs, hemoglobin infection - dec immunity acute chest syndrome - dec O2 pain - vascular occlusion and ischemia stroke - TCD monitoring cholecystitis - due to chronic hemolysis pulmonary HTN
What happens to the spleen as a result of sickle cell disease?
- enlarges at the end of first year of life
- remains enlarged due to splenic sequestration (pooling of sickled cells) and repeated infarction
- over time, spleen becomes fibrotic and shrinks (autosplenectomy), typically before the end of childhood
Mechanisms leading to splenomegaly (6)
- Conjestive* (cirrhosis - portal HTN, SV thrombosis)
- Immune response hypertrophy (bacterial endocarditis, infectious mononucleosis)
- RBC destruction hypertrophy (hereditary spherocytosis, thalassemia major)
- Myeloproliferative (chronic myeloid metaplasia)
- Infiltrative (sarcoidosis)
- Neoplastic (chronic lymphocytic leukemia, lymphoma)
When the spleen enlarges, what direction does it go in?
extends anterior, medial, and inferior
blood disorder resulting in uncontrolled RBC production causing hyperviscosity and hypercoagulation
Polycythemia Vera
Polycythemia Vera may be the result of(4)
splenomegaly
budd-chiari syndrome
portal vein thrombosis
splenic infarcts
How does a splenic artery aneurysm present on xray
calcified circle in the LUQ
Sonographic appearance of a splenic artery aneurysm
May appear as a cystic mass or if calcified, a hyperechoic shadowing foci typically in the area of the splenic hilum
Heterotaxy is due to early embryological disturbances that occur prior to the _____ week of gestation.
6th
Classifications of heterotaxy
- complete/situs inversus
- partial/incomplete situs inversus-limited number of organs are inversed or situs ambiguous (when a normally lateral organ is centrally located)
- polysplenia
- asplenia
Polysplenia is _____-sided predominance and is associated with what abnormalities (6)
left Multiple LUQ spleens biliary atresia/absent GB intestional malrotation azygous continuation of interrupted IVC renal agenesis cardiac defects
Asplenia is ____-sided predominance and is assoicated with what abnormalities (6)
right absent spleen ML liver and GB intetsional malrotation horseshoe kidney reversed positions of the Ao and IVC severe cardiac defects
With splenic trauma, what can result if the splenic capsule remains intact
subscapular or intraparenchymal hematomas
With spelnic trauma, what can result if the splenic capsule ruptures
perisplenic or intraperitoneal hematomas
-fluid tends to be loculated around the spleen but may spread within teh peritoneal cavity
FAST looks at which areas
peritoneum
pleural space
pericardium
-hemopericardium and hemothorax
Ultrasound appearance of intraperitoneal blood depnds on the ____, _____ and ____ state of the clot.
age, amount, physical state
timing of blood coagulation is not fully understood and acute bleeds may have various appearances
-most assume the hemoperitoneum will appear anechoic, although, could see irregularly marginated echogenic mass that may mimic that of an enlarged spleen
_______ is the volume of RBCs found in 100ml of blood. Blood spillage outside the circulatory system will result in a _____ _______.
hematocrit
decreased hematocrit
Posttraumatic splenosis
In a patient with hx of splenic rupture or surgery, splenic cells may implant throughout the peritoneal cavity resulting in an ectopic spleen
-often asymptomatic and may mimic otehr pathologies
Thymus
lymphatic organ
plays a vital role in the development of immune system during childhood
disproportionately larger in infants
as children grow, the thymu undergoes physiologic involution
