Page 1446 - Small Animal Internal Medicine, 6th Edition

1418 PART XIII Hematology

manipulation because trauma may induce considerable clinically recognized postsplenectomy sepsis at our clinic
artifactual changes, which would preclude interpretation of died within 12 hours of onset, despite aggressive treatment.
VetBooks.ir the specimen. The popliteal lymph nodes are easily acces- which the enlarged lymph node mechanically compresses
The clinician occasionally encounters a patient in
sible and are the ones usually excised in dogs and cats with
generalized lymphadenopathy.
marked clinical abnormalities, such as intractable cough-
Once a node is excised, it should be sectioned in half or occludes a viscus, airway, or vessel. This may result in
lengthwise, impression smears made for cytologic analysis, ing caused by tracheobronchial lymphadenopathy (see Fig.
and the node fixed in 10% buffered formalin (one part of 79.7), colonic obstruction caused by iliac lymphadenopathy,
tissue to nine parts of fixative). The specimen is then ready or anterior vena cava syndrome caused by cranial vena cava
to be sent to a laboratory for evaluation. Samples can also be and thoracic duct obstruction. Several treatment options are
saved for cytochemical or immunohistochemical evaluation, available for these situations. If the lymph node is surgically
ultrastructural studies, microbiologic studies, and/or molec- resectable, excision or drainage should be attempted. If the
ular evaluation, including a PCR assay for organisms or clon- node is not surgically resectable or if surgery or anesthesia
ality. The same guidelines apply to the preparation of splenic poses a high risk for the animal, one or more of the follow-
specimens. ing can be used:

1. Irradiation can shrink a neoplastic lymph node and ame-
MANAGEMENT OF liorate the signs in animals with primary or metastatic
LYMPHADENOPATHY OR neoplastic lesions. Antiinflammatory doses of corticoster-
SPLENOMEGALY oids can be used (0.5 mg/kg orally q24h) in animals with
fungal lesions such as Histoplasma-induced tracheobron-
As noted, no specific treatment exists for dogs or cats with chial lymphadenopathy.
local, regional, or generalized lymphadenopathy or diffuse 2. Intralesional injections of corticosteroids (prednisolone,
2
splenomegaly. Treatment should be directed at the cause(s) 50-60 mg/m ) can be successful in dogs and cats with
of the lymphadenopathy or splenomegaly rather than at the solitary lymphomas or metastatic mast cell tumors if irra-
enlarged lymph nodes or spleen. Exploratory celiotomies or diation is not feasible.
laparoscopy provide considerable information regarding the 3. Systemic antibiotic therapy may be beneficial in animals
gross morphologic characteristics of an enlarged spleen and with solitary suppurative lymphadenitis.
adjacent organs and tissues. However, direct visualization of
these structures may be misleading because differentiation Suggested Readings
of some benign splenic masses (e.g., hematoma, HA) from Ballegeer EA, et al. Correlation of ultrasonographic appearance of
their malignant counterpart (e.g., HSA) on the basis of gross lesions and cytologic and histologic diagnoses in splenic aspi-
morphology alone may be impossible. As discussed earlier rates from dogs and cats: 32 cases (2002-2005). J Am Vet Med
(see “Imaging”), in rare cases the surgeon may recommend Assoc. 2007;230:690.
to the owners that the animal be euthanized on the operating Clifford CA, et al. Magnetic resonance imaging of focal splenic and
table because it has a splenic mass and nodules in the liver, hepatic lesions in the dog. J Vet Intern Med. 2004;18:330.
only to find out that the hepatic nodules represent nodular Couto CG, et al. Benign lymphadenopathies. In: Weiss DJ, Wardrop
hyperplasia or EMH and the primary mass was actually KJ, eds. Schalm’s veterinary hematology. ed 6. Ames, Iowa: Wiley-
benign (e.g., HA or hematoma). Blackwell; 2010:412.
Splenectomy is indicated in the event of splenic torsion Couto CG. A diagnostic approach to splenomegaly in cats and dogs.
Vet Med. 1990;85:220.
(see Fig. 88.6, B), splenic rupture, symptomatic splenomeg- DeGroot W, et al. Primary splenic torsion in dogs: 102 cases
aly, or most splenic masses. The value of splenectomy is (1992-2014). J Am Vet Med Assoc. 2016;248:661.
questionable in dogs with immune-mediated blood disor- Ferri F, et al. Splenitis in 33 dogs. Vet Pathol. 2016;54:147.
ders, dogs and cats with splenomegaly caused by lymphoma Fife WD, et al. Comparison between malignant and nonmalignant
in which chemotherapy has not induced splenic remission, splenic masses in dogs using contrast-enhanced computed
and dogs and cats with leukemias. Splenectomy is contrain- tomography. Vet Radiol Ultrasound. 2004;45:289.
dicated in patients with bone marrow hypoplasia in which Gamblin RM, et al. Nonneoplastic disorders of the spleen. In:
the spleen is the main site of hematopoiesis. Ettinger SJ, Feldman EC, eds. Textbook of veterinary internal
Although rare, a syndrome of postsplenectomy sepsis has medicine: diseases of the dog and cat. ed 5. St Louis: Saunders;
been documented in approximately 3% of dogs that undergo 2000:1857.
this surgical procedure in our clinic. The syndrome is similar Horvath SJ, et al. Effects of racing on reticulocyte concentrations in
Greyhounds. Vet Clin Pathol. 2014;43:15.
to its human counterpart. Most dogs with postsplenectomy Huynh E, Berry CR. Small animal abdominal ultrasonography: the
sepsis evaluated at our clinic were undergoing immunosup- spleen. Today’s Veterinary Practice. March/April:93; 2017.
pressive therapy at the time of surgery or had undergone Jones ID, Lamb CR, Radiology RDV. Associations between dual-
splenectomy for a neoplasm. This sepsis is usually rapid in phase computed tomography features and histopathologic diag-
onset (hours to days), so prophylactic bactericidal antibiotic noses in 52 dogs with hepatic or splenic masses. Vet Radiol
therapy is recommended postoperatively. All dogs with Ultrasound. 2016;57:144–2016.