The Spleen

While scanning the spleen, you notice a small round mass that appears to be separate from the spleen in the region of the spleen hilum. The echotexture of the mass is similar to that of the spleen. What is the most likely diagnosis?

Accessory spleen. Usually measure 1.5 and 2 cm. Rare locations for an accessory spleen are pelvis and scrotum.

Why does the spleen enlarges in cases of liver cirrhosis?

Because the liver becomes fibrotic and the resistance to incoming blood increases .

Focal lesions of the spleen include...

Cysts, pseudocysts, infarcts, granulomas, abscesses, benign and malignant neoplasms, and metastases.

Erythropoiesis

Process of red blood cell production

Phagocytosis

Process used by the red pulp to destroy old red blood cells

Erythrocyte

Red blood cell, contains hemoglobin

Splenic pitting

Red blood cells that are abnormal BECAUSE they contain a granule, or even a parasite, are not culled. Rather, the nuclear ligaments or membrane inclusions are milked from the erythrocytes, and cleansed red blood cell returns to normal circulation.

What would cause a small, shrunken spleen?

Sickle cell anemia

A patient with sickle cell disease presents for an abdominal sonogram complaining of recent left upper quadrant pain. A hypoechoic wedge shaped lesion is seen in the spleen. what is this typical of?

Splenic infarct

Having difficulty locating the spleen in its normal location, in the left upper quadrant. As you scan the entire left side, you locate what appears to be the spleen in the left lower quadrant. What is the most likely diagnosis?

Splenic ptosis aka wandering spleen

which structures pass through the splenic hilum?

Splenic vein, splenic artery, and efferent lymphatics.

The spleen is ...

Surrounded by a fibrous capsule. Located in the left hypochondrium. Lies posterior to the stomach.

What other areas should be evaluated on a patient with splenic hematoma?

The entire spleen should be evaluated, including the splenic capsule. Also, the pelvis, paracolic gutters, and Morrison's pouch should be evaluated for free fluid.

In which cavity is the spleen located?

The spleen is in the peritoneal cavity, and is covered by peritoneum, except at the hilum.

How does the anatomy of the spleen allow for such an increase in size?

The spleen is loosely held in place by 3 ligaments, but does not have fixed peritoneal attachments. These ligaments allow the spleen to increase up to 10 its normal size.

What is the appearance of the spleen with trauma?

The spleen may appear normal, or if there is a parenchymal hematoma, a mass may be seen. The hematoma may be heterogeneous, isoechoic, anechoic, or hyperechoic. It may develop between the spleen and the capsule, double contour may be seen.

The spleen is made up of red and white pulp.

The white pulp is composed of lymphatic tissue. The red pulp is composed of venous sinuses capable of storing more than 300 ml of blood.

What is the wandering spleen at an increased risk for?

Torsion and infarction.

Leukocyte

White blood cell, protects and fights against infection in the body

The spleen is responsible for erythropoiesis from approximately the 5th. to the 6th. months of fetal life.

With age, the bone marrow assumes this function, but the spleen retains its capacity to produce RBC. Hematopoietic functions can be regained if chronic anemia develops or bone marrow parenchyma is lost.

The red pulp consists of

a meshowrk of blood filled venous sinuses and reticular splenic cords, termed the cords of Billroth.

what can cause reverberation artifacts, which can make it difficult to visualize the anterior portion of the spleen?

air in the left colic colon flexure.

Following a splenectomy...

an accessory spleen may enlarge and assume the functions of the removed spleen.

What is the imaging method of choice for determining the presence of malignant versus benign tumors?

artheriography

Hypersplenism

condition in which the spleen becomes increasingly active and then rapidly removes the blood cells, "blood cell destruction".

Why is the spleen commonly injured with blunt trauma?

due to its vulnerable location, its tissue is like a sponge, so it can be easily damaged and can cause a significant hemorrhage.

The red pulp is responsible for

filtering the peripheral blood, including removal of worn-out or defective blood cells, and the storage of platelets.

The most common benign vascular lesion of the spleen is the...

hemangioma

Which lab value decreases with spleen trauma?

hematocrit

A sonogram shows a mass anterior to the wall of the aorta, a fluid filled area in the left lower quadrant, and enlarged spleen, is indicative of?

hodgkins' lymphoma

What is the normal echognicity of the spleen?

homogenious, isoechoic to the liver

normal splenic parenchyma should appear

homogenous

leukopenia, a white blood cell count below 4,000/mm can occur with which conditions?

hypersplenism, viral infection, leukemia, diabetes, pernicious anemia, aplastic anemia, and polycythemia vera. All increase hematocrit values.

In patient with both Hodgkin's disease and non-Hodgkin's lymphoma, the spleen may contain focal

hypoechoic or hyperechoic masses, may exhibit diffuse splenomegaly or may appear sonographically normal.

Splenic culling function

identifies and removes abnormal erythrocytes

Patients who are

immunocompromised are more susceptible to fungal and bacterial abscesses of the spleen.

histoplasmosis

infection by a fungus found in the droppings of birds and bats in humid areas.

Individuals with asplenia are at high risk of..

infection with encapsulated bacteria. Partial development may also occur with situs inversus and cardiovascular anomalies.

only the lateral component of the spleen is visible as the transverse sections are made more in which direction

inferior

The white pulp is part of the immune system as

it is a source of lymphocytes, macrophages, and antibodies. In addition, the white pulp can phagocytose bacteria that have bypassed the lymph nodes.

The lienorenal ligament attaches the spleen to the..

left kidney

Patient who have undergone splenectomy, often suffer from

leukocytosis, decreased iron levels, greater volumes of circulating defective cells, and decreased immune function.

Most common malignant disease that affects the spleen is

lymphoma. Sonographically, splenomegaly may be present if the spleen is diffusely infiltrated.

on longitudinal sections, where is the extension of the superior splenic component compared to the inferior component?

medial

the following is produced by the spleen

monocytes, plasma cells, lymphocytes, nongrannular leukocytes.

Sonographic appearance of splenic abscess

most splenic abscesses are multiple and complex in appearance with mixed echogenic properties.

What is the most common cause of splenomegaly?

portal hypertension

While scanning the spleen, you notice multiple enlarged, tortuous vessels in the splenic hilum. Color doppler confirms that they are vascular in nature. Dilated vessels are also noted within the splenic parenchyma. what is the most likely cause of findings?

portal hypertension with collateral varices

Acquired spleen cysts are

post inflammatory, traumatic, or parasitic in origen.

What are the most common causes of splenomegaly?

single most common cause is portal hypertension. Other causes are inflammatory, such as mononeuclosis or endocarditis. Infiltrative diseases such as lymphoma. Hematologic, metabolic, and traumatic

Hemangiomas are the most common benign vascular neoplasm of the spleen.

sonographic appearance is variable, including well-defined, echopenic foci with enhanced through transmission, echogenic masses, and mixed complex masses. Rarely contain calcifications.

Patients with splenic infarcts are at risk for

splenic rupture. Signs to watch out for include increasing subcapsular hemorrhage, free peritoneal blood, and expanding liquefaction area within the infarct.

What is the most common sonographically abnormality of the spleen?

splenomegaly

The most common varice to occur in cases of portal hypertension is the

splenorenal collateral, which diverts blood from the splenic vein to the left renal vein and into the IVC.

The gastrosplenic ligament attaches the spleen to the...

stomach

The removal of defective and worn-out blood cells occurs in..

the cords of Billroth

When imaging the spleen in the sagittal plane, views should always include..

the left diaphragm to evaluate for ascites or pleural fluid and the interface with the left kidney.

Hodgkins' lymphoma (lymphoma)

the most common malignant disease that affects the spleen. Decrease echognicity of the spleen may be indicative of lymphoma.

Increased echognicity of the spleen may suggest.

the presence of myelofibrosis or infection

The phrenicocolic ligament helps support ...

the spleen's inferior end

splenic ptosis can occur if

the supporting ligaments are dysfunctional or lax, secondary to hormone changes during pregnancy. Other causes include, splenomegaly, trauma, extreme weight loss, weak abdominal muscles, and gastric distention.

A fibrous capsule surrounds the spleen and

trabeculae project from the capsule into the organ, dividing the spleen into several compartments. These compartments are filled with lymphoid tissue termed "splenic pulp".

Asplenia is a...

very rare condition that leads to a congenital absence of the spleen.

The spleen measures

12 cm in length, 7 cm in width, and 3 to 4 cm in thickness.

The spleen is considered enlarged when its length is greater than ...

13 cm

normal white blood cell count:

5,000 to 10,000 active WBC per microliter of blood.

Acquired aplasia and hypoplasia. (Aplasia: failure to function normally. Hypoplasia: inadequate or below-normal number of cells.)

A small nonfunctional spleen is associated with repeated infarction, as occurs with sickle cell anemia. In this cases, the spleen is small, fibrotic and calcified.

The spleen receives its blood supply from the splenic artery, which is a branch of the ...

Celiac axis

What is leukopenia?

Decreased white blood cell count, frequently a side effect of chemoteraphy

Leukopenia

Decreased white blood cell count, possibly the result of viral infection or leukemia

Leukocytosis

Elevated white blood cell count, usually due to infection

Splenomegaly

Enlarged spleen

what characteristics can confirm splenic abscess?

Gas is frequently present in splenic abscesses and it will appear as a highly echogenic area with ring-down artifact or dirty shadowing. Also, you may see air-fluid levels.

When splenomegaly occurs, the echogenicity of the spleen could be...

Hyperechoic or hypoechoic, but does not correlate with the cause of enlargement.

Anemia may be caused by

Hypersplenism

Functions of the red pulp ...

In cases of severe hemorrhage , the red pulp releases its reservoir into the blood stream. Responsible for removal of worn-out red blood cells. Removes defective cells, such as, sickle and thalassemic cells from circulation.

Hematocrit

Laboratory value of percentage of blood volume made up of red blood cells

Ligaments that help stabilize the spleen

Lienorenal ligament. Gastrosplenic ligament. Phrenicocolic ligament.

Splenic calcifications may be the result of ...

Pneumocystis jiroveci. Histoplasmosis. Tuberculosis. Resolved hematoma.

The splenic vein joins with the inferior mesenteric vein and can be seen posterior to the tail and body of the pancreas.

Posterior to the neck of the pancreas, the splenic vein joins with the superior mesenteric vein to for the main portal vein.

Infarct

Tissue death caused by an interruption of blood supply

In addition to splenomegaly, what other condition can cause a large spleen in a patient with infection?

adenitis

What is leukocytosis typically the response to?

bacterial infections

If a patient has histoplasmosis, the sonographic images may demonstrate?

calcifications?

What is the splenic shape or appearance on transverse sections?

crecentric

Adenitis

describes an enlarged lymphatic system secondary to infection.

The pitting function removes

iron and other needed substances from the erythrocytes.

The spleen is bordered by...

posterior to the stomach, lateral to the left kidney, splenic flexure, and pancreatic tail, and anterior to the diaphragm.

What is the typical appearance of the spleen in a patient with lymphoma?

sonographically, the spleen may appear normal or it may be diffusely enlarged. A focal mass may be seen and appear hypoechoic or hyperechoic. multiple nodules may also be seen.