Chapter 32 - Spleen and Liver Flashcards
What shape is the spleen described as in the text?
Falciform or sickle-shaped.
How many ligaments suspend the spleen within the peritoneal cavity?
Three ligaments: phrenicosplenic, nephrosplenic, and gastrosplenic.
What is the anatomical position of the spleen relative to the last ribs?
The base generally corresponds to the last three or four ribs, exceeding the 18th rib by 2 to 3 cm.
Where is the hilus of the spleen located?
On the visceral surface, where vessels, nerves, and lymphatic structures are present.
What type of blood vessel supplies the spleen?
The splenic artery, a branch of the celiac artery.
What is the color of the spleen as described in the text?
Bluish red to purple.
What is the role of the trabeculae in the spleen’s structure?
They extend into the substance of the spleen, supporting its structure
What characterizes the majority of splenic pulp in horses?
Red pulp, which is lobulated and lacks venous sinuses.
What is the primary function of the white pulp in the spleen?
It serves as the lymphatic tissue, involved in immune responses.
What cells are primarily found in the white pulp?
Lymphocytes, antigen-presenting cells, and macrophages.
What significant feature is noted about the splenic vein?
It is an affluent of the portal vein and lies caudal to the splenic artery at the hilus.
What anatomical structure provides sympathetic and parasympathetic innervation to the spleen?
The splenic plexus, branching from the celiac plexus.
What type of muscle fibers are found in the splenic capsule?
Smooth muscle cells.
How is the red pulp of the spleen organized in terms of blood flow?
It consists of arterial capillaries, pulp veins, and a reticular meshwork filled with macrophages and blood.
What is the function of the reticular meshwork in the spleen?
It supports lymphatic tissue and facilitates immune function.
What anatomical structure is found cranial to the hilus?
The facies gastrica, in contact with the left side of the greater curvature of the stomach.
What is the anatomical significance of the caudodorsal angle of the spleen?
It can be palpated per rectum.
What does the white pulp of the spleen contain that aids in its immune function?
Deep efferent lymphatic vessels and is organized around arterial vessels.
What percentage of the circulating erythrocyte mass can the equine spleen store?
Up to 50%.
What is the maximum splenic contraction reported with phenylephrine administration?
Up to 83% of the original splenic mass.
By what percentage does epinephrine reduce splenic length when administered as a bolus?
Approximately 68%.
What is the typical thickness of the spleen that indicates splenomegaly on ultrasonography?
Greater than 15 cm at midbody.
What specific type of immunoglobulin is produced in the spleen?
Immunoglobulin M (IgM).
What role does the spleen play in the removal of aged erythrocytes?
It phagocytoses old or abnormal erythrocytes using macrophages.
How is splenomegaly detected during a physical examination?
By rectal palpation revealing thickening and rounded caudal margins.
What diagnostic procedure uses ultrasound guidance for histologic evaluation of splenomegaly?
Percutaneous biopsy.
What gas is used for abdominal insufflation during laparoscopic procedures?
Carbon dioxide.
What is the typical insufflation pressure used during laparoscopy?
8 to 10 mm Hg.
What instruments are commonly used for laparoscopic biopsy of the spleen?
Laparoscopic scissors and uterine biopsy forceps.
What are the possible complications associated with splenic biopsy?
Bleeding, intestinal puncture, and exudate leakage.
What primary neoplastic diseases are reported involving the equine spleen?
Lymphosarcoma, metastatic melanoma, hemangiosarcoma, and extraadrenal paraganglioma.
What common clinical signs indicate splenic pathology in horses?
Recurrent abdominal pain, lethargy, poor performance, anemia, and weight loss.
What is the main purpose of splenectomy in horses?
Research purposes and treatment of various splenic diseases
What are some etiologies for secondary splenomegaly?
Neoplasia, hematoma, vascular infarction, splenic abscesses, and immune-mediated hemolytic anemia.
What specific infectious diseases can cause splenomegaly?
Babesiosis, theileriosis, ehrlichiosis, borreliosis, and equine infectious anemia.
What is the significance of splenic infarction in horses?
It can occur concurrently with splenomegaly due to venous thrombosis.
Which cells are responsible for phagocytosing debris in the spleen?
Macrophages (reticuloendothelial cells).
What is the common clinical manifestation of splenic abscessation?
Anorexia, weight loss, depression, fever, and abdominal pain.
What anatomical structures can be identified when using a laparoscope to examine the spleen?
Head of the spleen, left kidney, and nephrosplenic ligament.
What does an abdominal ultrasound help determine regarding the spleen?
The cause of splenic abnormalities.
How does the spleen’s structure contribute to its function in filtering blood?
Blood circulates through highly porous capillaries, allowing for the removal of old erythrocytes.
What is the term for the process by which the spleen recycles iron?
Iron recycling.
What is the role of the spleen in the immune response?
It affects antibody response and serves as a reservoir for lymphocytes.
What is the function of the splenic plexus?
It supplies the spleen with sympathetic and parasympathetic fibers.
How does splenectomy affect a horse’s resistance to blood protozoa?
It significantly reduces resistance, allowing subclinical infections to become patent.
What complication is associated with an enlarged spleen in terms of surgery?
It may complicate the surgical exploration due to increased volume of ingesta.
What diagnostic test is indicated for equine infectious anemia?
Coggins test (agar gel immunodiffusion test).
How might the body condition of a horse affect laparoscopic visibility?
Obesity can thicken the body wall, interfering with laparoscope movement.
What is the significance of identifying hypoechoic masses during an ultrasound of the spleen?
They may indicate conditions such as hematomas or splenic tumors.
What are some indications for performing a splenectomy?
Trauma, primary splenomegaly, neoplasia, and autoimmune disease.
What potential effects do autoimmune diseases have on the spleen?
They can lead to erythrocyte destruction.
What type of neoplastic condition is lymphosarcoma classified as?
A neoplastic disease of lymphoid cells.
What is the role of splenic lymph nodes in relation to the spleen?
They drain lymph to the celiac lymphocenter.
What clinical signs are associated with splenic infarction?
Symptoms of systemic disease, which may include abdominal pain and anemia.
What happens to the spleen during severe stress or exercise?
It contracts to release stored erythrocytes into circulation.
What type of test is recommended before performing a splenic biopsy?
A complete coagulation profile to ensure normal function.
What specific type of fluid appearance on ultrasound suggests a hemoabdomen?
A swirling cellular appearance in hypoechoic effusion.
What is the relationship between splenic disease and recurrent colic in horses?
Both primary and idiopathic splenomegaly have been attributed to recurrent colic.
What is the primary cause of splenic rupture in horses?
Often attributed to direct, severe trauma to the spleen.
What are the common clinical signs of splenic rupture in horses?
Signs include pale mucous membranes, anemia, tachycardia, dyspnea, and abdominal pain.
How many cases of nonfatal subcapsular hematoma have been reported?
Four cases.
What imaging techniques can differentiate between hematoma and rupture?
Laparoscopy and ultrasonography.
What are the key preoperative considerations for a horse undergoing splenectomy?
Assessment of hydration, electrolyte and acid-base status, and coagulation parameters.
-Blood donor crossmatch perfomed
-Starving for 24-48h to improve visualization
-Screen piroplasmosis if endemic zone
What is the recommended fasting period before elective splenectomy?
24 to 48 hours.
What is the most common approach for performing splenectomy in horses?
An open approach from the left side.
What rib resection techniques have been described for accessing the spleen?
Resection of the 16th, 17th, or 18th ribs, and modifications of the paralumbar incision.
What percentage of the pleural cavity may be entered during rib resection?
Entering the pleural cavity is almost always expected when ribs are resected.
What is the purpose of administering phenylephrine prior to vessel ligation?
To induce transient splenic contraction and improve access to splenic vessels.
What technique can be used to perform a partial splenectomy?
Use of a TA-90 stapling device.
What type of sutures are recommended for minor spleen lacerations?
Absorbable sutures placed across the defect. Take large bites to avoid tension on suture line
Use swaged needle
How long should horses be hand-walked post-splenectomy?
For the first 7 to 10 days.
What should be monitored daily in the surgical incision after splenectomy?
Signs of heat, swelling, drainage, seroma formation, or infection.
What are the main aftercare considerations for a horse post-splenectomy?
Monitoring vital signs and the incision site, and administering antibiotics if needed.
What is the role of laparoscopic techniques in splenectomy?
To assist in ligation of splenic vessels and improve visualization.
What are the two ligation techniques mentioned for splenic vessels?
Triple ligation and using a polyamide cable for vascular occlusion.
What medication may be used to assist with hemorrhage control during surgery?
Antifibrinolytic agents. Antifibrinolytic agents such as aminocaproic acid or tranexamic acid can also be used to promote hemostasis
What complications are more likely to develop in obese horses post-splenectomy?
Incisional complications such as seromas.
What is the risk associated with the entrance of the pleural cavity during splenectomy?
Pneumothorax.
Which ligaments are transected during splenectomy?
The nephrosplenic, phrenicosplenic, and gastrosplenic ligaments.
What type of drains may be utilized post-splenectomy?
Active or passive drains.
What is the significance of crossmatching blood before splenectomy?
To ensure compatibility for potential blood transfusions due to acute blood loss.
What is a common clinical sign of splenic abscessation?
Anorexia.
Which surgical device is mentioned for managing hemorrhage during splenectomy?
LigaSure (coagulating hemostatic device).
What is the general method of closure for the abdominal wall after splenectomy?
In three layers: peritoneum, subcutaneous tissues, and skin.
What anesthetic position is used for the 17th rib resection technique?
Right lateral recumbency.
What is the role of systemic epinephrine in splenectomy?
To reduce the weight of the spleen by inducing contraction.
What can be expected if the pleural cavity is entered during surgery?
Assistance with ventilation may be required.
How is the splenic vein located in relation to the splenic artery?
The vein is more superficial or lateral than the artery.
What specific anesthetic monitoring is suggested for horses post-splenectomy?
Breathing assistance may be required if the pleural cavity is entered.
What types of cultures are recommended for guiding antimicrobial therapy in cases of infection?
Bacterial culture and sensitivity testing.
Figure 32-6. Intraoperative view showing elevation of the dorsal part of the spleen into the incision. The nephrosplenic ligament prevents complete elevation of the spleen.
Figure 32-2. Left view of the (A) spleen, (B) stomach, and (C) left kidney with pertinent vascular supply. Retractors are placed along the greater curvature of the stomach to reveal the short gastric arteries and veins and along the dorsal extremity of the spleen to show the left kidney. Parts of the stomach are identified with special labels.
Figure 32-9. Relative topography of the abdominal viscera as viewed from the right side. The lateral and ventral walls are removed. The proximal one-third of the last nine ribs shows the relative position of the liver protected by the rib cage (18th rib defines the ventral and caudal border of the rib cage). A, Right liver lobe; B, quadrate liver lobe; C, right dorsal colon; D, cecum; E, right kidney; F, descending duodenum; G, diaphragm.
Figure 32-1. Relative topography of the abdominal viscera as viewed from the left side. The lateral and ventral walls are removed. The proximal one-third of the ribs show the relative position of the spleen and liver protected by the rib cage (the 18th rib defines the ventral and caudal border of the rib cage). A, Spleen; B, left dorsal colon; C, left ventral colon; D, left liver lobe; E, stomach; F, diaphragm; G, jejunum
