Spleen Flashcards
The most common anomaly of splenic embryology is?
the accessory spleen
Accessory spleen seen in what % of pts?
20%
80% of accessory spleens are found where?
splenic hilum and vascular pedicle
other areas; gastrocolic ligament, pancreatic tail, greater omentum, stomach greater curvature
What organs surround the spleen?
greater curvature of stomach
splenic flexture of colon
apex of left kidney
tail of pancreas
What ligaments tether the spleen in place?
spleno-colic ligament
gastro-splenic ligament
phreno-splenic ligament
spleno-renal ligament
Which ligament tethering the spleen contains vessels?
gastro-splenic ligament—> short gastrics
spleno-renal ligament–> splenic artery and vein and tail of pancreas
the remaining ligaments are avascular
Relationship between spleen and panrceas?
tail of pancreas lies within 1 cm of spleen 75% of time
known to abut the spleen in 30% of pts
What ribs protect spleen on left?
ribs 9, 10, 11
Spleen derives it’s blood supply from where?
splenic artery
Splenic artery can be characterized by the pattern of its terminal branches, which are?
magistral (30%)
distributed (70%)
What splenic artery branching type most common?
distributed–> short trunk with many long branches enter spleen
What is the magistral splenic artery pattern?
magistral–> long trunk, with few short branches entering spleen
Aside from the splenic artery the spleen also receives some its blood supply from?
short gastrics in the gastro-splenic ligament
What is the venous drainage of the spleen?
splenic vein–> joined by the SMV to enter into the portal vein
Parenchyma of spleen is made up of two parts:
red pulp (75% of splenic volume)
white pulp
In the spleen, the red pulp and white pulp interface where?
at the narrow marginal zone
Function of red pulp?
macrophages phagocytize aging RBCs as they try to pass
This component of the spleen serves as a filtration system, allowing macrophages to remove microorganisms, cellular debris and aging RBCs;
red pulp
What is the white pulp of the spleen?
at the end of splenic arterioles we have a peri-articular lymphatic sheath made of B cells and T cells
Between the white and red pulp we have the marginal zone, what cell types reside there?
macrophages
White pulp is involved in what type of immunity?
adaptive
Innate immune function of spleen occurs via?
marginal zone macrophages
The spleen acts as major site of clearance for what?
aging RBCs
Of a RBCs 120 days life cycle, how much of that time do they spend in the spleen?
2 days
spleen removes 20 cc of aging RBCs from circulation
What 3 things does the spleen produce?
opsonins
tuftins
properidin
What splenic product initiates alternate pathway of complement activation:
properidin
Splenomegaly vs hypersplenism:
splenomegaly–> abnormal enlargement of spleen
hypersplenism–> presence of one or more ctyopenias in context of normal functioning bone marrow
Half life of a neutrophil vs platelet?
neutrophil–> 6 hrs
platelet—> 10 days
OPSI is commonly caused by encapsulated organisms such as:
strep pneumo
h. flu
neissieria meningitidis
What causes hereditary spherocytosis?
deficiency/dysfunction in one of the erythrocyte membrane proteins; spectrin, ankyrin, band 3 protein
This is an inherited disorder where we have dysfunction of one of the erythrocyte membrane proteins like spectrin and ankyrin;
hereditary spherocytosis
WHat happens to RBCs in hereditary spherocytosis?
bilipid membrane layer is destabilized, get pathological release of membrane lipids
RBC becomes spherical, less deformable, gets trapped in spleen and destroyed
This is an AD dx affecting spectrin, a RBC cytoskeleton protein;
hereditary spherocytosis
Inheritance patterns of hereditary sphercytosis?
AD
What are some clinical findings and lab values we see with hereditary spherocytosis?
mild jaundice
splenomegaly on exam
varying degrees of anemia
spherocytes seen on blood smear
Why is cholecystectomy performed for hereditary spherocytosis?
pts have increased risk of pigmented stone formation due to destruction of RBCs
Most common hemolytic anemia for which splenectomy is indicated?
HS
When do we remove the spleen in someone with hereditary spherocytosis?
symptomatic hemolytic anemia
growth retardation
skeletal changes
extramedullary hematopoietic tumors in young pts
If gallstones co-exist with hereditary spherocytosis what do we do?
splenectomy + cholecystectomy
**prophylactic cholecystectomy is not indicated
When performing splenectomies in children affected by HS, at what age do we perform it?
by age 5
Why do we wait to perform splenectomies for HS in children until age 5?
preserve immune fx of spleen
reduce risk of OPSI
What are the two hereditary conditions assc with hemolytic anemias?
pyruvate kinase deficiency
G6P dehydrogenase deficiency
This d/o is is an AR disease that results in decreased RBC deformability and the formation of echinocytes:
PK deficiency
This is the most common RBC enzyme deficiency;
PK deficiency
FOr which inherited enzyme deficiency d/o is splenectomy indicated?
PK deficiency
Primary treatment for G6P deficiency?
NOT splenectomy
avoid foods, drugs that can precipitate a crisis
This is an X-linked inherited d/o affecting more people worldwide that PK deficiency;
G6P deficiency
Primary treatment of G6P deficiency?
void foods, chemicals, drugs that exacerbate hemolytic episodes
most pts have mild to mod sxs
THis is an autoimmune d/o characterized by low platelet count, mucocutaneous and petechiae bleeding;
ITP
What causes the low platelets seen in ITP:
premature removal of platelets opsonized by anti-platelet IGG made by the spleen
Typical presentation of ITP includes?
purpura epistaxis gingival bleeding (less common; gi bleeding, hematuria) (rare but fatal; intracranial bleeding)
Diagnosis of ITP involves what?
exclusion of other causes of thrombocytopenia
Incidence of major intracranial bleeding from ITP?
1%
Difference in presentation of ITP in children vs adults?
children; often present at young age, with sudden onset of petechiae, purpura days/weeks after an infectious process
adults; have a more chronic form of dx, with insidious onset
How common is splenomegaly with ITP?
uncommon
ITP predominantly affects men or women?
young women
First line therapy for ITP?
oral predinose 1.0 mg/kg/day
most responses occur with first 3 weeks
When do we give IVIG for ITP?
usually for internal bleeding, in pregnant pts, pts being prepped pre-op
Dose of IVIG for ITP?
1g/kg for 2-3 days
When do we perform splenectomies for ITP?
pts with plts <10K for 6 weeks or longer
thrombocytopenia refractory to steroid therapy
pts who require toxic steroid doses for remission
How is sickle cell disease inherited?
autosomal co-dominant
pts can be carriers who inherit one abnormal gene from one parent (heterozygous)
pts can have the disease if they inherit two abnormal genes (homozygous)
What causes sickle cell dx?
mutated adenine to thymine in 6th codon of B-globin gene
valine substituted for glutamic acid
Valine substituted for what in sickle cell dx?
glutamic acid
Common reasons for splenectomy in pts with sickle cell dx?
recurrent sequestration crises
hypersplenism
splenic abscess
What medication can we use in sickle cell dx?
hydroxyurea
How does hydroxyurea work for sickle cell dx?
upregulates fetal Hgb
What is a target cell?
RBC with nucleus in tact
This d/o characterized by thrombocytopenia, microangiopathic hemolytic anemia and neurological disorders;
TTP
What causes TTP?
large multimers of VW factor assc. with platelet clumping in pt’s blood
What are the clinical features of TTP?
petechiae fevers neuro sx renal sx cardiac sx
The diagnosis of TTP is confirmed by blood smear, which shows what?
schistocytes
nucleated RBCs
basophilic stippling
Tx for TTP?
plasma exchange is first line
splenectomy for pts who relapse or require multiple exchanges
Where do we find accessory spleens commonly?
hilum 54%
pedicle 25%
greater omentum 12%
tail of pancreas 6%
What is Hodkin’s dx?
malignant lymphoma affects adults in their 20’s 30s
How do pts with Hodkin’s dx typically present?
cervical lymphadenopathy
rarely present with constitutional sxs
What are the different types of Hodkin’s dx?
lymphocyte predominant
nodular sclerosing
mixed cellularity
lymphocyte depleted
How do we classify Hodkin’s dx?
Ann Arbor classification system
What’s the Ann Arbor classification system of Hodkin’s dx?
Stage 1 –> single lymphatic site
Stage 2–> 2 or more lymphatic sites on same side of diaphragm
Stage 3–> disease on both sides of the diaphragm w/splenic involvement
Stage 4–> disease disseminated into extralymphatic sites like liver, lung, bone marrow
Most common primary splenic neoplasm?
NHL
Hairy cell leukemia is a rare disorder, characterized by what?
splenomegaly
pancytopenia
neoplastic mononuclear cells in the peripheral blood
What chromosomal marker associated with CML?
philadelphia chromosome; 9;22
Chromosome 9 and 22 fuse, causing expression of a bcr/abl gene product, a tyrosine kinase which accelarates cell division and impairs DNA repair, this is seen in what?
CML
Chromosome seen in CML, coding for bcr/abl tyrosine kinase?
9;22
Solid tumors that most frequently spread to the spleen?
breast
lung
melanoma
Angiosarcomas of the spleen have been linked to what environment exposures?
vinyl chloride
thorium dioxide
How do we classify splenic cysts?
true cysts (can be parasitic vs non-parasitic)
pseudocysts
True cysts of spleen are lined with a squamoues epithelium and stain for what 2 markers?
CEA
CA 19-9
Primary true cysts of spleen make up what %?
10% of all non-parasitic splenic cysts
Most non-parasitic splenic cysts are?
pseudocysts due to trauma
Are true splenic cysts malignant?
benign
Operative intervention for splenic cysts?
indicated for pts with symptoms and those w/large cysts
When performing partial splenectomies for symptomatic or large cysts, what % of spleen remnant needed to protect against pneumococcal pneumonia?
25%
Most true splenic parasitic cysts and occur in endemic areas such as:
Echinococcus species
What do we see on imaging of splenic cysts suspected to be echinococcal?
cyst wall calcificatons
daughter cysts
What do we worry about with parasitic splenic cysts?
rupture into abdomen
spillage of cyst contents and an anaphylactic rxn
Tx of choice for parasitic cysts?
splenectomy
Other tx for parasitic cysts beside splenectomy?
inject cyst with 3% NS
alcohol or silver nitrate
avoid rupture intra-op
What makes a pseudocyst of the spleen a pseudocyst?
not lined by epithelium
These makes up 70-80% of non-parasitic splenic cysts:
pseudocysts due to trauma
What is the size cutoff for pseudocysts treatment?
asymptomatic <4 cm cysts involve with time
Mortality rates of splenic abscesses?
15-20% in healthy pts
80% in immunocompromised pts
70% of splenic abscesses are due to hematogenous spread from?
endocarditis
osteomyelitis
IV drug use
How do we diagnose splenic abscesses?
CT
Tx of splenic abscess depends on what?
whether it’s unilocular or multilocular
1/3 of adult pts, splenic abscess tend to be what?
multilocular
1/3 of children pts, splenic abscces tend to be what?
unilocular
What is the tx for unilocular vs multilocular splenic abscesses?
unilocular—> percutaneous drainage + abx
multilocular–> splenectomy, drainage of LUQ, abx
How common are splenic abscesses?
uncommon
0.14–0.7%
Infectious mononucleosis due to EBV or CMV imparts a small risk of?
splenic rupture
splenic parenchyma infiltrated by inflammatory cells–> thins the capsule
rupture can occur after minor trauma
Common organisms isolated from splenic abscesses?
streptococci and e.coli **MC
others; mycobacteria tb, salmonella
MCC of splenic cysts worlwide?
parasites like echinococcus
SPlenic cysts resulting from trauma are called?
pseudocysts
What Ca most commonly spreads to spleen?
lung
In terms of splenic artery aneurysm who is more affected men or women?
women 4;1
In what part of splenic artery do we commonly seen splenic artery anuerysm?
mid to distal
When do we treat splenic artery aneurysms?
presence of sxs
pregnancy
intent to get pregnant
Tx for splenic artery aneurysms?
aneurysms in mid portion–>resection or ligation
distal portion–> need splenectomy
Rheumatoid arthritis, neutropenia, splenomegaly make up what ?
Felty syndrome
Preferred method of splenectomy?
laparoscopic
barring trauma and massive splenomegaly
Disadvantage of laparoscopic splenectomy?
longer op times
difficult removing large organs
When do we give vaccines prior to elective splenectomies?
2 weeks prior
Most common fatal late complication of splenectomy?
OPSI
After splenectomies when do we see OPSI?
most occurred after 2 yrs
42% occurred after 5 yrs
OPSI as a result of dog bites due to what bacteria?
capnocytophaga canimorsus
OPSI is greatest in pts who have had splenectomies for what?
hematologic disorders rather than trauma
For post-splenectomy pts when do we give vaccines?
within 2 weeks of splenectomy if pt did not receive before surgery
What vaccines do we give in splenectomized pts?
PPV23 (polyvalent pneumococcal vaccine)
h flu type B conjugate
meningococcal polysaccharide vaccine
OPSI is more common children or adults?
adults
risk greatest within first 2 yrs
What bacteria responsible for >50% of OPSI?
s. pneumo
For emergent splenectomy cases why do we wait 2 weeks to vaccinate pts post-op?
transient immunosuppressions assc w/surgery
What is the overall incidence of OPSI?
<1 %
Most common method of intra-op splenic injuries?
improper splenic traction against its peritoneal attachments
causes capsular tears
lower pole more commonly injured to greater peritoneal attachments in lower pole
What causes OPSI in splenectomized pts?
loss of splenic macrophages
diminished tuftsin production
loss of spleens reticuloendothelial system
*** in normal pts, these three things work together to opsonize bacteria from bloodstream
Most common complication after open splenectomy?
left lower lobe atelectasis
Most common indication for open splenectomy?
trauma
Incision for open splenectomy?
left subcostal incision along left costal margin
2 fingerbreadths below
midline incision preferred when spleen ruptured or massive
In splenectomies how do we gain access to lesser sac?
free up the gastro-splenic ligament
WHere do we find the splenic artery?
superior border of pancreas
When doing splenectomies for enlarged spleen why ligate splenic artery first?
easier to mobilize spleen
easier to dissect hilum
allows spleen to shrink a bit
allows for transfusion of RBCs and platelets
After open splenectomy do we leave a splenic drain in place?
not routinely done
**risk of subphrenic abscess
How do we mobilize the spleen in open splenectomies?
mobilize the spleno-colic ligament first
mobilize spleno-phrenic ligament
mobilize and ligate short gastrics
dissect hilum, ligate artery then vein
Gold standard approach to splenectomy in pts with normal sized spleens?
laparoscopic
