Gastrointestinal and Abdominal: Spleen

Question 1

Spleen

Answer 1

The spleen is a lymphatic organ located in the left

upper abdominal quadrant. It contains the largest

accumulation of lymphoid cells in the body. In addi-

tion to filtering the blood, it plays an important role

in host defense. Splenic lymphocytes are involved

in antigen recognition and plasma cell production,

whereas splenic endothelial macrophages extract bac-

teria

and damaged red blood cells from circulation

by phagocytosis. White pulp of the spleen contains

high concentrations of antigen-presenting cells and

receives arterial blood supply first. Blood then trav-

els through an open-type circulation known as the

red pulp, where foreign particles are filtered and

antibody-coated cells are removed. Removal of red

blood cell imperfections is another function of the

spleen. These include Howell-Jolly bodies (Fig 8-1),

which are nuclear remnants, Pappenheimer bodies,

which are iron inclusions, and Heinz bodies, which

are denatured hemoglobin. Splenectomy or hypos-

plenism is associated with the presence of these

abnormalities in the peripheral blood.

Surgical issues regarding the spleen are multiple

and varied. Life-threatening hemorrhage from a lac-

erated spleen resulting from trauma is a common

problem, requiring swift surgical intervention. Certain

disease states, such as immune thrombocytopenic

purpura (ITP) and the hemolytic anemias, are often

treated with splenectomy when medical manage-

ment fails. Splenectomy may be necessary as part of

another operation, such as distal pancreatectomy. In

addition, the traditional staging workup for Hodgkin

disease has involved removal of the spleen to deter-

mine extent of disease, although this is now rarely

performed.

Question 2

Spleen: Anatomy

Answer 2

The spleen is embryologically derived from condensa-

tions of mesoderm in the dorsal mesogastrium of

the developing gastrointestinal tract. In the mature

abdomen, the spleen is found attached to the stomach

by the gastrosplenic ligament and to the left kidney by

the splenorenal ligament. Other supporting attach-

ments include the splenocolic and splenophrenic liga-

ments (Fig. 8-2).

Accessory spleens are present in approximately

25% of patients. They are most often found in the

splenic hilum and in the supporting splenic ligaments

and greater omentum.

Arterial blood is mostly supplied via the splenic

artery, which is one of three branches of the celiac

axis (splenic, left gastric, common hepatic). At the

hilum, the splenic artery divides into smaller

branches that supply the several splenic segments.

Additional arterial blood is supplied via the short gas-

tric and left gastroepiploic vessels (Fig. 8-3).

Venous drainage is from segmental veins that join

at the splenic hilum to form the splenic vein.

Running behind the upper edge of the pancreas, the

splenic vein joins with the superior mesenteric vein

to form the portal vein.

Question 3

Splenic Hemorrhage

Answer 3

The most common cause of splenic hemorrhage is

blunt abdominal trauma. Nonpenetrating injury may

cause disruption of the splenic capsule or frank lacera-

tion of the splenic parenchyma. Displaced rib fractures

of the left lower chest often cause splenic laceration.

Splenic injuries are graded from I to V based on the

extent of laceration and hematoma (Table 8-1).

Splenic hemorrhage may also be iatrogenic.

Intraoperative damage to the spleen may occur dur-

ing unrelated abdominal surgery that results in bleed-

ing controlled only by splenectomy. Estimates are

that 20% of splenectomies result from iatrogenic

causes. Infectious diseases (e.g., mononucleosis,
malaria) may damage the spleen to the point that

unnoticed blunt trauma can cause “spontaneous” splenic

rupture and hemorrhage.

Question 4

Splenic Hemorrhage: History

Answer 4

Patients typically present with a recent history of

trauma, usually to the left upper abdomen or left flank.

Question 5

Splenic Hemorrhage: Physical Examination

Answer 5

Depending on the degree of splenic injury and hemo-

peritoneum, a physical examination may reveal left

upper quadrant abdominal tenderness, left lower rib

fractures, abdominal distention, peritonitis, and

hypovolemic shock. Pain on the left shoulder is referred to as

Kerr’s sign and is referred pain from peritoneal irritation.

Question 6

Splenic Hemorrhage: Diagnostic Evaluation

Answer 6

Computed tomography (CT) scan, abdominal ultra-

sound, and peritoneal lavage (see Chapter 27,

Trauma) can be used to detect intraperitoneal blood.

In hemodynamically stable patients, CT can demon-

strate the degree of both splenic injury and hemo-

peritoneum.

Question 7

Splenic Hemorrhage: Treatment

Answer 7

For patients with splenic injury who are hemody-

namically stable and without evidence of ongoing

hemorrhage, nonoperative management with close

hemodynamic monitoring has become the accepted

treatment of choice. In children, nonoperative man-

agement is widely applied as a result of the incidence

of overwhelming postsplenectomy sepsis seen in the

pediatric population. Recent advances in interven-

tional radiology have made it possible to embolize

the spleen, or a portion, to obviate the need for

laparotomy. This can have the advantage of salvaging

enough of the spleen to prevent major complications,

such as postsplenectomy sepsis, but splenic abscess

may occur. For patients with known or suspected

splenic injury who are hemodynamically unstable,

operative intervention is indicated to control ongoing

hemorrhage.

Once in the operating room, the decision to per-

form splenic repair (splenorrhaphy) versus splenec-

tomy is based on the degree of injury to the par-

enchyma and blood supply of the organ. Relatively

minor injuries, such as a small capsular laceration

with minor oozing, may be repaired, whereas a frag-

mented spleen with involvement of the hilar vessels

necessitates surgical removal. If splenic repair is con-

templated, the spleen must be mobilized completely

to determine the extent of injury and the likelihood

of success. If there are other organs injured in addi-

tion to the spleen, splenectomy is generally recom-

mended.

Question 8

Immune Thrombocytopenic Purpura

Answer 8

ITP is an autoimmune hematologic disease in which

antiplatelet IgG antibodies, produced largely in the

spleen, are directed against a platelet-associated antigen,

resulting in platelet destruction by the reticuloendothe-

lial system and subsequent thrombocytopenia. The dis-

ease is typically seen in young women, who may present

with complaints of menorrhagia, easy bruising, mucosal

bleeding, and petechiae. Men may present with com-

plaints of prolonged bleeding after shaving trauma.

Question 9

Immune Thrombocytopenic Purpura: Treatment

Answer 9

Initial therapy is with corticosteroids, which improve

platelet counts after 3 to 7 days of therapy. Initial

doses are 1 mg/kg orally until the platelet count is

normal, followed by a 4- to 6-week taper. High-dose

dexamethasone or methylprednisolone is also an

option. Intravenous immunoglobulin can be used

to support the platelet count, as can anti-Rh(D) if

patients have Rh(D) positive platelets. For prolonged

active bleeding, platelet transfusions should be

administered to achieve hemostasis. If patients are

asymptomatic, platelet counts of

30,000 can be tol-

erated. Once patients become symptomatic or the

platelet count decreases to

10,000, therapy should

be considered. Patients with chronic refractory ITP

may benefit from rituximab or thrombopoiesis-

stimulating agents, but these are considered experi-

mental at this time.

Few patients enjoy complete and sustained remis-

sion with corticosteroid treatment alone. Patients typ-

ically become refractory to medical treatment, and

thrombocytopenia recurs. Splenectomy is then indi-

cated. After splenectomy, normal platelet counts

develop in approximately 80% of patients because

the organ of both significant antiplatelet antibody

production and platelet destruction is removed.

Question 10

Hypersplenism

Answer 10

Hypersplenism describes a state of increased splenic

function that results in various hematologic abnor-

malities, which can be normalized by splenectomy.

Elevated splenic function causes a depression of the

formed blood elements, leading to a compensatory

hyperplasia of the bone marrow.

Question 11

Hypersplenism: History

Answer 11

As in ITP, most patients are women who present with

signs of anemia, recurrent infections, or easy bruising.

Question 12

Hypersplenism: Physical Examination

Answer 12

Abdominal examination reveals splenomegaly.

Question 13

Hypersplenism: Diagnostic Evaluation

Answer 13

Peripheral-blood smear may reveal leukopenia, ane-

mia, thrombocytopenia, or pancytopenia. Bone mar-

row biopsy shows pancellular hyperplasia.

Question 14

Hypersplenism: Treatment

Answer 14

Splenectomy may produce hematologic improvement.

Question 15

Hemolytic Anemias

Answer 15

Hemolytic anemias are characterized by an elevated

rate of red blood cell destruction from either a

congenital or acquired etiology. Congenital hemolytic

anemias result from basic defects of the cell membrane

(hereditary spherocytosis), hemoglobin synthesis

(thalassemia), hemoglobin structure (sickle cell anemia), or

cellular metabolism (glucose-6-phosphate dehydroge-

nase deficiency). Acquired autoimmune hemolytic

anemias result when antibodies are produced that are

directed against the body’s own red blood cells.

Question 16

Hemolytic Anemias: Diagnostic Evaluation

Answer 16

A positive direct Coombs test demonstrates com-

plexed antibodies on the red blood cell membrane.

Warm-reactive antibodies are IgG, and cold-reactive

antibodies are IgM.

Question 17

Hemolytic Anemias: Treatment

Answer 17

The role of splenectomy in treating hemolytic anemias

depends on the particular disease process. For example,

red blood cell survival normalizes after splenectomy for

hereditary spherocytosis, whereas operative interven-

tion has no role in the treatment of anemia of glucose-

6-phosphate dehydrogenase deficiency that is second-

ary to a defect of metabolism, not cellular structure.

Occasionally, splenectomy may be useful in selected

patients with sickle cell anemia and thalassemia.

Patients with autoimmune hemolytic anemias undergo

nitial corticosteroid treatment and progress to splenec-

tomy only after medical treatment failure.

Question 18

Hodgkin Disease Staging

Answer 18

Because of a greater reliance on CT scans and the favor-

able success of salvage chemotherapy in the treatment

of Hodgkin lymphoma, the need for determining

whether disease is present across the diaphragm by

means of laparotomy and splenectomy has sharply

declined. Treatment with salvage chemotherapy after

local radiation failure still carries a highly favorable out-

come in most cases. Therefore, splenectomy for staging

Hodgkin disease is now rarely performed.

Question 19

Overwhelming Postsplenectomy Sepsis

Answer 19

Asplenic individuals are at greater risk for developing

fulminant bacteremia because of decreased opsonic

activity, decreased levels of IgM, and decreased clearance

of bacteria from the blood after splenectomy. As a rule,

children are at greater risk for development of sepsis

than are adults, and fatal sepsis is more common after

splenectomy for hematologic disorders than after

trauma. The risk of sepsis is higher in the first postoper-

ative year, and, for adults, each subsequent year carries

approximately a 1% chance of developing sepsis. Other

data show a mortality of less than one per 1,000 patient-

years. The clinical picture of overwhelming postsplenec-

tomy sepsis is the onset of high fever followed by

circulatory collapse from septic shock. Disseminated

intravascular coagulation often occurs. The offending

pathogens are the encapsulated bacteria

Streptococcus

pneumoniae, Haemophilus influenzae,

and

Neisseria

meningitidis.

Question 20

Splenectomy Considerations

Answer 20

Any patient scheduled to undergo splenectomy

should receive immunization against Steptococcus

pneumoniae, Haemophilus influenzae, and Neisseria

meningitidis, preferably at least 2 weeks before surgery.

Straightforward splenectomy can be performed laparo-

scopically, whereas complicated splenectomy in patients

with massive spleens or severe thrombocytopenia are

more likely to require laparotomy. During surgery, the

spleen is mobilized from the splenorenal, phrenosplenic,

and lienocolic ligaments. The main artery is found on

the superior border of the pancreas and should generally

be taken early. Care must be taken to control the short

gastric arteries entering the greater curve of the stom-

ach. The tail of the pancreas nestles into the splenic

hilum and can be damaged, causing a pancreatic leak

or fistula. Patients generally have nasogastric decom-

pression to prevent the stomach from distending and

hemorrhage along the greater curve. Patients with com-

promised immune systems, including young children

and transplant recipients, should be considered for long-

term oral penicillin prophylaxis.

Question 21

Splenic Abscess

Answer 21

Splenic abscesses most commonly occur as a conse-

quence of other intra-abdominal infection. They can

also occur after arterial embolization of either the

liver or spleen. Diabetes seems to be a risk factor.

Patients generally present with left upper quadrant

pain, fever, and leucocytosis. Antibiotics, catheter-

based drainage, and splenectomy are all appropriate

management options.

Question 22

Key Points: Spleen

Answer 22

The spleen is a lymphatic organ that plays roles in

antigen recognition and blood filtering.

•

Accessory spleens occur in 25% of patients and are

most commonly found in the splenic hilum.

•

Arterial blood is supplied via the splenic artery, the

short gastric arteries, and branches of the left gas-

troepiploic artery.

•

Hemorrhage secondary to trauma is the most com-

mon indication for splenectomy.

•

Nonoperative management or organ-sparing splen-

orrhaphy can be attempted to avoid the risk of

overwhelming postsplenectomy sepsis, especially

in children.

•

Hemodynamically stable patients with splenic

injury can be managed nonoperatively.

•

Immune thrombocytopenic purpura, hypersplenism,

and specific hemolytic anemias are disease states for

which splenectomy may be indicated.

•

Splenectomy for staging Hodgkin disease is now

rarely performed, because of improved imaging

modalities (computed tomography scan) and the

success of chemotherapy.

•

The risk of overwhelming postsplenectomy sepsis

is greater in children than in adults. High fever and

septic shock are often accompanied by dissemi-

nated intravascular coagulation.

•

Vaccination against

Streptococcus pneumoniae,

Haemophilus influenzae,

and

Neisseria meningitidis

should be administered to all surgically and func-

tionally asplenic patients, because these encapsu-

lated organisms are responsible for causing over-

whelming postsplenectomy sepsis.