Surgery of the Spleen Flashcards
The head of spleen is attached to which aspect of the stomach and how?
Greater curvature; gastrosplenic ligament
The celiac artery which branches from the A) divides into B (3) arteries
A) abdominal aorta
B) hepatic, left gastric and splenic
Branches from the splenic artery supply the pancreas and there are branches that travel cranially and then through the A) ligament to supply the short gastric arteries.
gastrosplenic
At the level of the mid-spleen the splenic artery becomes the ? artery which branches to supply the caudal spleen.
left gastroepiploic
Physiological functions of the spleen?
Haematopoiesis
Immune response
Reservoir
Although splenic haematopoiesis is unusual in adults, it can occur in response to?
Demands from chronic hypoxia
The spleen is a major site of ? in foetal development.
extramedullary haematopoiesis
Red blood cells (RBCs) spend several days in the spleen following production; then what happens? (3)
Cell size is reduced,
the cell is contoured into a disc like shape
intracellular material is removed.
Old and/or damaged red blood cells may also be removed from circulation in the spleen
What is recovered from these cells; where are they stored and transferred to?
Iron recovered from these cells is stored in the spleen and then transferred to the bone marrow.
Filtration of microorganisms from the blood via ? is a key function of the spleen.
phagocytosis
What immune cells does the spleen produce a significant number of? (3)
B
T
IgM
Immunity in the spleen:
A microorganism will arrive and be taken up by?
A splenic macrophage
Following splenic macrophage; this then leads to the production of B-cells which generate A). . B) are recruited and prevented from leaving the site of antigen presentation to maximise the immune response.
A) antibodies
B) Lymphocytes
Neutrophil A) and B) activation also occur in the spleen.
A) phagocytosis
B) complement
This immune function can have a negative role as well as it is here that red blood cells and platelets covered in antibody are removed from circulation in i? (2)
Immune mediated thrombocytopaenia (IMTP) and immune mediated haemolytic anaemia (IMHA).
In dogs, what % of RBC can be stored in the spleen?
20
In dogs what % of platelets can be stored in the spleen?
30
Physiological demands can cause contraction of the spleen via smooth muscle stimulation and vasopressors leasing to 98% of the blood moving into the rapid pool which takes just 30 seconds to cross and re-enter the circulation. What happens to splenic size in this time?
Splenic size at this point can be as little as ¼ of normal.
Generalised splenomegaly can occur due to (4)
inflammation, hyperplasia, congestion or infiltration.
Splenic inflammation or splenitis can be due to exposure to ?
an infectious organism (bacteria, virus, fungi or protozoa).
If the splenitis is infectious then ? will be the dominant cell population, and this can lead to localised abscessation in some cases.
neutrophils
Eosinophilic splenitis can be seen in some cases secondary to?
eosinophilic gastroenteritis.
In cats, cases of Feline Infectious Peritonitis can have a ? splenitis.
pyogranulomatous
Emboli or thrombi that occlude the splenic vasculature can lead to hypoxic areas and growth of ? spp. and necrotising splenitis.
Clostridium
(2) can lead to splenic macrophage hyperplasia and splenomegaly.
Leishmaniasis and histoplasmosis
(2) can lead to B-cell and T-cell lymphoid hyperplasia.
Chronic osteomyelitis or bacterial endocarditis
A splenomegaly associated with splenic myeloid metaplasia and histiocytosis has been reported with what prognosis?
poor prognosis, 70% of dogs died within a year of splenectomy
Splenic congestion can cause generalised splenomegaly and can be seen with changes in vascular pressure such as (3)
with congestive heart failure
portal hypertension
increased outflow resistance such as in a vascular obstruction.
What drugs can relax smooth muscle of the splenic capsule leading to splenomegaly? (2)
Barbituate
PHenothiazine
Splenic amyloidosis and lysosomal storage diseases can also cause generalised splenomegaly. How common?
Rare
Localised splenomegaly is common in dogs. It can have a number of causes, the most common are? (3)
Nodular hyperplasia
Haematoma
Haemangiosarcoma
In dogs, splenic neoplasia is commonly..?
Localised