Flashcards in Small Animal Splenic Disorders Deck (38)
Where is the spleen located?
In the cranial abdomen towards the left hand side
What is the anatomy of the spleen?
Dorsal extremity (head) which is fixed by gastrosplenic ligament and a ventral extremity (tail) which is relatively more mobile
How are structure and function of the spleen linked?
Smooth muscle capsule so it can significantly contract or swell in size
What is the blood supply to the spleen?
Splenic artery arises from celiac artery and divides into approximately 25 small hilar arteries which enter the spleen on its concave surface
Splenic vein drains into the portal vein
What are some important branches of the splenic artery/vein?
Left limb of the pancreas
Greater curvature of the stomach (left gastroepiploic)
Fundus of the stomach (short gastic)
What is the function of the spleen?
Red blood cell maintenance, iron metabolism, blood reservoir, haematopoiesis, immune functions
How does the spleen perform red blood cell maintenance?
Filtration of blood and phagocytosis, remodelling of red blood cells, removal of intra-erythrocytic inclusions
How does the spleen contribute to iron metabolism?
Significant iron stores result from continuous removal of old or damages red blood cells
How does the spleen act as a blood reservoir?
10-20% blood volume stored in dogs and cats which are readily available in case of acute blood loss/haemolysis
How does the spleen act as a haematopoietic organ?
Can resume haematopoietic functions in adult animals to help out when bone marrow cannot carry out its normal haematopoietic role
What are the immune functions of the spleen?
Major site for clearance of micro-organisms and providing an immune response protecting against septicaemia
Where are the functions of the spleen carried out?
First four functions carried out in red pulp and immunological functions carried out in white pulp
Why is a splenectomy performed?
Due to suspected neoplasia or due to rupture
How is a splenectomy performed?
Large ventral midline abdominal incision, begin removal at tail end double ligating vessels, when reach the head try and preserve short gastric vessels and transect gastrosplenic ligament
What is the quick way of performing a splenectomy?
Ligate the short gastric vessels and left gastrosplenic a + v and the splenic a + v distal to the branch supplying the pancreas
When is a partial splenectomy performed?
Localised benign disease
How is a partial splenectomy performed?
Hilar vessels to diseased portion are ligated and transected resulting in an obvious demarcation between ishcaemic and normal spleen which is used as a guide for resection then transect the spleen using one of two methods
What are the two methods of transecting the spleen in a partial splenectomy?
Squeeze along demarcation towards end to be removed and place forceps on flattened portion, divide spleen between the forceps and place two rows of mattress sutures in a continuous overlapping pattern and close cut end of spleen using continuous suture pattern
Use a stapler
What are the perioperative considerations for splenectomy?
High risk of cardiac arrhythmias, coagulation tests should be performed, large abdominal incision should be made, abdominal retractors and suction make job easier, examine entire abdomen for neoplasia, need lots of haemostatic forceps and swabs, measure blood loss
How is blood loss measured?
Measure blood in suction bottle and weight swabs (1ml blood = 1.3g)
What other operation should be considered in large deep chested dogs following splenectomy?
Gastropexy to reduce risk of GDV
What are the potential complications of splenectomy?
Haemorrhage due to technical failure or DIC
Ischaemic pancreatitis and gastritis
Possible increased risk of infection
What are some causes of localised splenomegaly?
Haematoma, abscess, nodular hyperplasia, infarction, cyst, haemangioma, leiomyoma, fibroma, lipoma, haemangiosarcoma, fibrosarcoma, leiomyosarcoma
What are some causes of diffuse splenomegaly?
Infection, congestion due to drugs/splenic torsion/GDV/right sided heart failure, acute and chronic leukaemia, systemic mast cell tumour, lymphoma, multiple myeloma, malignant histiocytosis, immune-mediated thrombocytopaenia
How useful is an FNA in diagnosing splenic disease?
May be very useful in differentiating certain causes of diffuse splenomegaly however often just produces blood when aspirating localised haematoma or haemangiosarcoma
What are the characteristics of haemangiosarcomas?
Most common malignant splenic tumour in the dog
GSD at increased risk
Aggressive and frequently metastasise to liver, omentum, mesentery, brain, right atrium and subcutaneous tissue
How is haemangiosarcoma diagnosed?
Grossly indistinguishable from haemangioma or haematoma and requires pathology
All dogs should have thoracic radiographs/CT to check for metastasis
What is the treatment for haemangiosarcoma?
Splenectomy is palliative with survival of 3-12 weeks
Post operative chemotherapy prolongs life for around 6 months normally using cyclophosphamide/doxorubicin protocol for 6 cycles
In which breeds is splenic torsion seen in?
Deep chested breeds such as Great Danes/Irish Setters