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284 Edema, Subcutaneous

of dogs will still have urinary inconti- and fluid overload may indicate possible urinary SUGGESTED READING
nence after surgical correction due to tract obstruction. Davidson AP, et al: Diagnosis and management of
VetBooks.ir Technician Tips Client Education AUTHOR: Laura A. Nafe, DVM, MS, DACVIM
concurrent urethral sphincter mechanism
urinary ectopia. Vet Clin North Am Small Anim
incompetence.
Pract 44:343-353, 2014.
Understanding that a large percentage of dogs
Immediate postoperative monitoring should with ectopic ureters continue to have urinary EDITOR: Leah A. Cohn, DVM, PhD, DACVIM
incontinence after repair of the ectopic ureter(s)
focus on urine production and fluid volume is important when discussing surgery and
status because signs of reduced urine production postoperative expectations with clients.

Edema, Subcutaneous

BASIC INFORMATION are consistently well-defined, even in obese • Increased vascular permeability
animals. With edema, these areas are less ○ Allergic response (histamine release)
Definition defined and overlying skin has a thickened, ○ Acute inflammation
Local or generalized swelling from excessive jelly-like appearance. ○ Burn injury
fluid accumulation in the interstitial tissue • Edema tends to accumulate where gravity ○ Envenomation
spaces under the skin. Normally, only a small draws it, where lymphatic obstruction or Normal volume of interstitial fluid not reab-
amount of fluid leaks from vessels into the insufficiency is greatest, or a combination sorbed by the lymphatic system:
interstitium, and it is removed by lymphatic of both. The pattern of edema distribution • Lymphatic obstruction (usually localized)
vessels. varies. ○ Neoplasia
• Additional physical abnormalities depend ○ Inflammation
Synonyms on underlying cause of edema. ○ Trauma
Peripheral edema (edema of the head, neck, ○ Congenital (lymphedema)
torso, and/or limbs), anasarca (generalized, Etiology and Pathophysiology
massive subcutaneous [SQ] edema) More fluid leaves the capillaries than enters: DIAGNOSIS
• Increased vascular hydrostatic pressure
Epidemiology ○ Right-sided CHF Diagnostic Overview
SPECIES, AGE, SEX ○ Impaired venous flow (e.g., mediastinal • SQ edema is identified on physical exam
Dogs and cats: any age, either sex or abdominal mass) (readily if severe, with difficulty if mild).
○ Iatrogenic fluid overload • Diffuse edema, or edema in disparate loca-
RISK FACTORS ○ Excessive fluid retention (e.g., anuric tions, suggests systemic disturbance. Regional
Severe hypoproteinemia, right-sided congestive kidney failure) edema (e.g., head/neck, single limb) suggests
heart failure (CHF), inflammation, vasculitis, • Decreased plasma oncotic pressure regional disease.
extensive trauma or heat, lymphatic malforma- ○ Hypoalbuminemia: increased loss or • Acute edema is more likely related to causes
tion, acquired venous or lymphatic obstruction decreased production (p. 1239) such as allergy, envenomation, or thermal
(e.g., tumor, granuloma)
Clinical Presentation
HISTORY, CHIEF COMPLAINT
Regional swelling (e.g., one limb, both hind
limbs, head) or a diffusely swollen appearance,
most commonly in dependent areas (e.g.,
sternum, distal limbs, scrotum)
PHYSICAL EXAM FINDINGS
• Local or diffuse thickening of SQ tissues
○ Most commonly, edema pits. Digital pres-
sure exerted on edematous skin may leave
a depression (i.e., pit) for several seconds
after the pressure is released, when fluid
accumulation is interstitial rather than
intracellular.
○ Although uncommon, swelling may
be painful or warm if associated with
infection.
○ Sometimes associated with ascites (e.g.,
hypoalbuminemia, right-sided CHF)
• The hock with its lateral saphenous vein,
the gastrocnemius tendons, and the bony EDEMA, SUBCUTANEOUS Subcutaneous edema in the tarsal region of a dog. In this image, the clinician
prominence of the mandible are useful to just removed her index finger after applying digital pressure for several seconds, revealing the depression or
evaluate for SQ edema because these areas pit (arrows) that characterizes pitting edema.

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