Small Animal Splenic Disorders Flashcards Preview

Lymphoreticular and haematopoetic > Small Animal Splenic Disorders > Flashcards

Flashcards in Small Animal Splenic Disorders Deck (38)
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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
Cardias arrhythmias
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


What happens in a splenic torsion?

Spleen twists on its vascular pedicle occluding the hilar vessels