Spleen power point Flashcards
}Normal texture and patterns
◦The splenic parenchyma should have a fine uniform homogeneous mid- to low-level echo pattern, as is seen within the liver parenchyma.
◦The texture of the spleen is actually considered to be more echogenic than the liver.
◦As the spleen enlarges, the echogenicity increases further.
Sonographic Evaluation
of the Spleen
The parenchyma is homogenous throughout, except for the area of the hilum where the vascular structures enter and leave.
Normal spleen
}Best visualized with deep inspiration
}Patient lying RLD or supine
}Concave inferior border and a convex superior border
}Size varies with age, normally decreasing in advanced age and enlarges when pathology is present Normal adult 8-13cm in length
>13cm is considered splenomegaly
}Splenic hilum located along the medial surface
Sonography of the spleen
}Located in the left hypochondrium (page 121)
}Very posterior organ lying between the fundus of the stomach and the diaphragm
}The lower medial surface is in contact with stomach, left kidney, pancreas, and splenic flexure of the colon.
}Covered by a protective capsule except at the hilum where vessels enter and exit and lymph nodes are located
Relational anatomy of the spleen
◦Peritoneal ligament that attaches the spleen to the stomach and the kidney.
Is in contact with the posterior peritoneal wall, the phrenicocolic ligament, and the gastrosplenic ligament
}Splenorenal ligament
◦Composed of the two layers of the dorsal mesentery that separate the lesser sac posteriorly from the
greater sac anteriorly
}Gastrosplenic ligament
}The spleen is held in place by the lienorenal, gastrosplenic, and phrenocolic ligaments.
}A mass in the left upper quadrant may displace the spleen inferiorly.
}Caudal displacement
Cephalic displacement
Displacement of the Spleen
}may be secondary to a subclavian abscess, splenic cyst, or left pleural effusion.
Caudal displacement
}may result from volume loss in the left lung, left lobe pneumonia, paralysis of the left hemidiaphragm, or a large intraabdominal mass.
Cephalic displacement
}Splenic artery, branch of the celiac trunk from the aorta
}Splenic artery is very tortuous and travels horizontally along the superior border of the pancreas to the splenic hilum
}Once the artery enters the spleen it branches into 6 smaller arteries to profuse the spleen. These are normally not seen on gray scale, but can be visualized by color or power doppler
Arterial vascular supply
}Splenic vein is formed by multiple branches within the spleen, leaves the hilum and joins the superior mesenteric vein to form the main portal vein
}Splenic vein travels along the posteromedial border of the pancreas
Venous vascular supply
}Functions:
}Breakdown of hemoglobin
}Formation of bile pigment
}Formation of antibodies and immunity
}Red blood cell production
Physiology of the spleen
}Part of the reticuloendothelial system
}Considered the largest lymphatic organ
}Begins to develop around the fifth week of gestation
}Active in blood formation during the initial part of fetal life (Hematopoiesis)/ (erythropoiesis) RBC,
}This function decreases gradually by the fifth or sixth month when the spleen assumes its adult characteristics and discontinues this function
} Plays an important role in the defense of the body, esp in childhood
}Storage of iron
}Blood reservoir
}Although it is affected by systemic disease process, it is rarely the cause of them
Spleen
Red pulp-
White pulp
}Spleen also removes irregular cells from the bloodstream and retains them through a process called culling
}Spleen can clean red blood cells of unwanted material through a process called pitting
Specialized tissue
performs the lymphatic function by producing lymphocytes to aid in the immune response
White pulp
}performs phagocytosis- this is where the phagocytes engulf and destroy pathogens
Red pulp-
hematocrit
bacteremia
WBC count
WBC count
Lab values
percentage of RBC’s per volume of blood. Decrease may indicate internal bleeding or hemorrhage in the body
hematocrit
}presence of bacteria in the body. If bacteria is found within the blood, termed sepsis blood cultures
Bacteremia
}too high, indicates infection. May also be elevated post surgical, malignancies, and leukemia (leukocytosis)
too low, indicates bone marrow disorder or may be secondary to medications(leukopenia)
Platelet count-too low, indicates internal hemorrhage(thrombocytopenia
WBC count-
}Results when the dorasal mesentery fails to fuse with the posterior peritoneum without supporting ligaments of the spleen
}Clinically, patient presents with an abdominal or pelvic mass, intermittent pain, spleen may twist and torsion may occur
}Wandering spleen (ectopic)
Agenesis
polysplenia
accessory spleen
Congenital Anomalies
called asplenia – rare, may be part of a major fetal anomaly or syndrome associated with cardiac malformations
agenesis
-numerous small spleens – again associated with major fetal anomaly/syndromes
}Polysplenia
}most common may be found in approx 30% of patients Results from the failure of fusion of separate splenic masses forming on the dorsal mesogastrium
Accessory spleen-
}Sonographically, same echotexture and echogenicity of the spleen
}Normal size is small, approx 1 cm
}Usually solitary
}Normal location is splenic hilum, but can be found near the tail of the pancreas
}Also called a splenule or splenunculus
}As the spleen enlarges, so will the accessory spleen
Accessory spleen
}Seen in patients with sickle cell anemia
}Due to excessive loss of pulp and scarring
}In the final stages, spleen may be unrecognizable
}Referred to as autosplenectomy
Atrophy of the spleen
