Small Animal Splenic Disorders Flashcards
Which ends of the spleen are fixed and free?
- tail ventral and free
- head fixed by gastrosplenic ligament
What is the capsule of the spleen made from?
smooth muscle
Where does the splenic artery arise from? What does it divide into?
celiac artery -> 25 hilar arteries (small) enter the spleen on concave surface
Where does the splenic vein drain to?
portal vein
What are the important branches of the splenic artery/vein supplying?
- left limb of pancreas (important as only blood supply)
- greater curvature of the stomach (left hastroepiploic, less critical)
- fundus of stomach (short gastrics, not too critical)
Which vessels are first to rupture in GDV?
short gastrics (in a healthy animal this doesn’t cause too much problem)
How is the pancreas associated with the spleen?
If spleen lifted up with mesentry, pancreas lies underneath
Where do the splenic a and v lie?
in the mesentry
Does splenectomy cause problems for animals?
-not as serious as in humans (septicaemia risk ^)
Outline 5 main fucntions of the spleen
> RBC maintainance
- filtration and phagocytosis, removing intraerythrocytic inclusions (eg. Heinz bodies)
Iron metabolism
- removal of old RBCs
Blood reservoir
- esp canine and feline (10-20% blood volume)
Haematopoiesis
- can resume haematopoietic functions if BM compromised
immune function
Where are the different functions carried out?
- RBC maintainance, iron metabolism, blood reservoir and haematopoiesis = red pulp
- immune function WBC
Can the spleen be biopsied pre-op?
Not really , will just get blood
What should be done before splenectomy if neoplasia is suspected?
Staging to adivise owner
Outline long procedure for total splenectomy
- start tail end
- double ligate and transect hilar vessels
- reach head, try and preserve short gastric vessels
- transect gastrosplenic ligament
Outline quick spelenctomy technique
- ligate short gastric vessels
- ligate left gastroepiploic a and v and splenic a + v distal to branch supplying pancreas
> may be impossible if ruptured splenic mass or distorted anatomy present (torsion/GDV) - be careful not to ligate branch supplying pancreas ( lies close to hilar branches)
When is partial spleenectomy indicated?
localised, benign disease (hard to prove this)
Outline partial splenectomy technique
- hilar vessels ligated
- leave to observe area of ischaemia
- squeeze towards end being removed
- place DOYEN intestinal forceps
- remove disease porion
> 2 rows mattress sutures in a continuous overlapping patern - close cut end using continuous (fine absorbable suture)
> OR staple (quicker)
What are dogs with splenic masses at higher risk of? How can these risks be managed?
> cardiac arrhythmias - ECG monitor - fluid tx - antidysrhythmics rarely > DIC [neoplastic or torsion] - pre-op coagulation tests (PT, APTT) - esp if intra-ab haemorrhage seen > people not sure why these links exist
Considerations perioperatively for splenectomy
- waterporroff drapes
- haemostatic forceps and swabs
- count in and out
- measure blood suction bottle and weigh swabs (1ml blood = 1.3g)
- gastropexy in pdf breeds for GDV (no evidence to support currently)
- monitor vitals and PVC/TP postop ash ameorrhage main complication
Main complications of splenectomy
> haemorrhage (technical failure or DIC)
cardiac arrhythmias
poss ^ risk infection (onlyif immunosuppressed)
previous subclinical infection with haemoparasites eg. Babesia, Ehrlichia, Mycoplasma may become evident
Ddx of splenomegaly
> localised (dogs)
- neoplastic (benign: haemangioma, leiomyoma, fibroma, lipoma) (malignant: HS, fibroS, leimyoS, sarcomas in general)
-non-neoplastic (haematoma, abscess, nodular hyperplasia, cyst, infarction - infarction usually many concurrent medical problems)
diffuse (cats)
- infection (bacterial, fungal, viral, parasitic)
- congestion (drugs eg. barbituates, splenic torsion and/or GDV, RSHF)
- neoplasia (acute/chronic leukaemia, systemic MCT esp cats, lymphoma, multiple myeloma, malignant histiocytosis)
- immune-mediated thrombocytopaenia (splenectomy only performed if animal refrctory to tx with immunosuppressive drugs)
What is the best method of differentiating splenomegaly? Which kind of splenomegaly is it best for?
FNA for DIFFUSE
- for localised haematoma/haemangiosarcoma often blood only
ULTRASOUND to differentiate spleen and liver and find mets
What is the most comon malignant splenic tumour in the dog?
Hemangiosarcoma (esp GSD)
Outline characteristics of splenic HS
- aggressive, freq metastasise to liver, omentum, mesentry, brain, RA and subcut
- 25% dogs with splenic HS have concurrent RA
- grossly indistinguishable from haemangioma or haeatoma (and challenging even with histopath)
What further diagnostics should be performed if a splenic mass is found?
> cannot distinguish haematoma, haemangioma and haemangiosarcoma
- thoracic rads or CT to look for pulmonary mets for staging
When may a non-disease spleen appear enlarged?
Some sedative drugs can relax smooth muscle -> capsular swelling and enlargement
Tx for HS with no evidence of metastasis? Prognosis?
- splenectomy
- only palliative
- survival ~3-12weeks ( ~6months survival
What 2 pathologies are failry rare for the spleen?
- torsion
- trauma
How does splenic torsion occour and how can it be dx?
- deep chested dogs (think GDV)
- spleen twists on vascular pedicle, ocluding hilar vessels
> acute presentation with abdo pain, distenion, shock
> chronic form intermittent and v hard to dx - US = enlarged spleen, unique pattern of linear echos (“SNOWSTORM”)
Tx splenic torsion?
- splenectomy
- do NOT Untwist pedicle before removing (will cause reperfusion injury and release of vasoactive mediators)
- divide and ligate the pedicle
Px splenic torsion?
after successful splenectomy prognosis is EXCELLENT
How does splenic trauma usually occour?
- surgical trauma (accidental incision) or serious RTA etc.
- if RTA related, other wounds usually more serious and haemorrhage will either self resolve while treating other things or they are so severe that the injuries are fatal
Tx splenic laceration surgically?
- suture sapsule
- suture omentum over laceration
- severe or persistnet haemorrhage -> splenectomy to deal with any ischaemia
What may occour after rupture of the spleen?
- multiple small splenic nodules called splenosis may be seen thorughtout the abdomen
