Hemolymphatic System

Question 1

Define splenosis

Answer 1

“Splenosis is the congenital or traumatic presence of multiple nodules of normal splenic tissue in the abdomen”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
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Question 2

Why should the splenic artery never be ligated immediately after it’s branching from the celiac artery?

Answer 2

The splenic artery will produce three main branches. The first of which provides blood supply to the left limb of the pancreas. Ligation proximal to this branch will lead to loss of blood supply to a large portion of the pancreas, potentially leading to serious consequences.

Question 3

Explain the venous drainage from the spleen

Answer 3

“Venous drainage occurs via the splenic vein into the gastrosplenic vein, which empties into the portal vein.”

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Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 4

Explain the arterial and venous supply to the spleen

Answer 4

Question 5

Should cavitary splenic lesion be sampled via ultrasound guided FNA? What are the risks?

Answer 5

“When cavitary lesions are identified with ultrasound scans, FNA should be performed with care or not at all. Cavitary lesions may rupture during aspiration, which could be fatal, especially in animals with coagulopathies.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 6

What is the specificity and sensitivity of FNA for splenic lesions?

Answer 6

“FNA can be specific (e.g., if malignant cells or yeast forms are found) but is not particularly sensitive. Aspirate cytology is much less sensitive for splenic lesions than for lymph node lesions, and it is particularly insensitive for differentiating hemangiosarcoma from hematoma ”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 7

What are the main splenic functions that can be used to justify performing partial splenectomy for a single lesion versus total splenectomy?

Answer 7

“The spleen normally contains a reservoir of RBCs, has hematopoietic capabilities, has important phagocytic functions, and is helpful in maintaining immunocompetence; total splenectomy eliminates these beneficial actions. ”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 8

What CBC abnormalities may be observed after splenectomy? What abnormalities are considered “normal” and which are concerning?

Answer 8

“Mild postoperative leukocytosis may occur after splenectomy in dogs because the spleen influences bone marrow leukocyte production; however, steep or prolonged elevations may indicate infection (e.g., splenic abscess or peritonitis). An increase in the numbers of Howell-Jolly bodies, nucleated erythrocytes, target cells, and/or platelets may be noted after splenectomy but is not a cause for concern.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 9

List five potential complications of splenectomy

Answer 9

• hemorrhage (most common and important complication)
• Abscessation (more likely in immune-suppressed patients)
• traumatic pancreatitis,
• gastric necrosis due to impairment of gastric bloodflow
• exacerbation of previously silent clinical infections (Babesia, Ehrlichia, mycoplasma)

Question 10

What are the two ligaments that provide stability to the spleen?

Answer 10

Gastrosplenic and splenocolic ligaments

Question 11

Primary lymphedema is relatively rare in dogs, and caused by genetic abnormalities of lymphatics or lymph nodes. What are the most common causes of Secondary Lymphedema?

Answer 11

“Secondary lymphedema occurs as a result of lymphatic obstruction of the nodes or vessels by neoplasia, infection (e.g., filariasis), lymphoproliferative disorders, or some other infiltrative process or surgery.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 12

Typical clinical presentation for a patient with lymphedema

Answer 12

“Lymphedema typically manifests as a spontaneous, painless swelling of the extremities with pitting edema. The onset may be insidious. The rear limbs are more commonly affected, and the swelling may be unilateral. Lymphedema usually begins in the distal extremity and progresses proximally. In severely affected animals, all four limbs and the trunk may be edematous. Although the patient may be less active than normal because of the weight of the limb or may carry the limb when ambulating, lameness and pain are uncommon without massive enlargement or cellulitis.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
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Question 13

You are presented with a patient with significant pitting edema affecting one of the pelvic limbs. The limb is not painful or unusually warm. You suspect lymphedema. What is the other most important differential diagnosis?

Answer 13

“The key differential diagnosis is abnormality of the venous system, such as venous stasis or arteriovenous fistula. The clinical signs are usually adequate to differentiate lymphedema from edema caused by venous obstruction. Typical changes with edema caused by venous obstruction include varices, stasis hyperpigmentation, and cutaneous ulceration”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 14

Are diuretics indicated for the long-term treatment of lymphedema? Why?

Answer 14

“Long-term treatment of lymphedema with diuretics is contraindicated. Diuretics act by removing fluid from the tissue; proteins that are not reabsorbed become increasingly concentrated, further damaging tissues.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 15

Is classic massage therapy indicated for the treatment of lymphedema?

Answer 15

“Classic massage therapy is generally contraindicated in extremities affected with lymphedema because it increases the arterial blood flow. This results in an increase in blood capillary pressure and subsequent increase in ultrafiltration of water in the area of the capillaries, which leads to an accumulation of fluid in the interstitial space and increased lymphatic load. In addition, superficial lymphatics are vulnerable to external pressure and traditional massage techniques may cause focal damage to anchoring filaments and the endothelial lining of the lymph vessels.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 16

Benzopyrones are a group of drugs used to treat lymphedema in dogs and humans. What is the proposed mechanism of action? Well tolerated? Examples

Answer 16

“Benzopyrones (Box 23.1) are a group of drugs that have been used to successfully treat experimental lymphedema in dogs and spontaneous lymphedema in human beings. All the drugs in this group appear to reduce high-protein edema. Their main action appears to be stimulation of macrophages, which promotes proteolysis. Protein fragments can then be reabsorbed into the blood. These drugs are active orally and topically, are inexpensive, and are relatively free of side effects. Included in this category of drugs are coumarin (5,6 benzo-[a]-pyrone), O-(β-hydroxy-ethyl)-rutosides, diosmin, and rutin.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 17

Medical therapies are rarely effective to treat lymphedema. What is the recommended surgical therapy for a patient with a single affected limb?

Answer 17

“Medical therapy is often ineffective in substantially reducing swelling caused by lymphedema; however, medical management has received little attention in veterinary medicine. Amputation is a reasonable alternative for unilateral lymphedema, particularly when it interferes with limb function and when initial medical management is ineffective.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 18

Discuss the basic anatomy of the lymphatic system draining the pelvic limbs

Answer 18

“The lymphatic system of the extremities can be divided into two parts: superficial and deep (i.e., muscular) lymphatics. The superficial system appears to be the one most commonly involved in lymphedema. This is the system of lymphatics observed during pedal lymphangiography (Fig. 23.6). These lymphatics empty into a valved group of vessels found at the junction of the dermis and subcutaneous tissue. Lymph then drains into afferent lymphatics in the subcutaneous fat. The superficial lymphatics of the pelvic limb consist of a larger medial group and a smaller lateral group. Lymphatics follow the branches of the medial saphenous vein and drain into the superficial inguinal lymph nodes. Efferent lymphatics from the lymph nodes drain into the larger lymphatic ducts. The deeper lymphatics drain the fascial planes surrounding skeletal muscles (lymphatics are not found in skeletal muscle bundles), joints, and synovium. Deep lymphatic collector vessels accompany the main blood vessels of the extremities. Controversy continues as to whether the two lymphatic systems (superficial and deep) communicate; however, communications usually appear to be a result of a lymphatic pathologic condition or a response to abnormal lymph flow. The lumbar lymph trunks receive vessels from the pelvic limbs, the abdominal lymph nodes and the intestines before uniting to form the cisterna chyli.”

Excerpt From
Small Animal Surgery E-Book
Theresa Welch Fossum DVM, MS, PhD, Dipl ACVS
https://books.apple.com/us/book/small-animal-surgery-e-book/id1367916984
This material may be protected by copyright.

Question 19

According to Stockdale et al, what was the effect of performing cysterna chyli ablation in addition to thoracic duct ablation and subtotal pericardectomy in cats with chylothorax?

Answer 19

Prolonged surgical time
No improvement in outcome

Google Docs. “Comparison of Thoracic Duct Ligation plus Subphrenic Pericardiectomy with or without Cisterna Chyli Ablation for Treatment of Idiopathic Chylothorax in Cats.Pdf.” Accessed January 17, 2024. https://drive.google.com/file/d/1nTr7OZaIEOMY9Rcv–K06m62x3uP7clz/view?usp=embed_facebook.