Page 1752 - Cote clinical veterinary advisor dogs and cats 4th

879.e4 Renomegaly

• Polyuria/polydipsia (p. 812) • Assess size of both kidney, presence of which one is abnormal until radiography or
ultrasound is performed.
• Signs of uremia (e.g., anorexia, vomiting, pyelectasis, corticomedullary distinction, • Ureteral obstruction is more common than
VetBooks.ir • Rarely, abdominal distention (p. 1192) • More sensitive for small uroliths and ureteral once thought. Rapid referral for ureteral
renal parenchyma echogenicity
weight loss) (p. 169)
obstruction than radiographs
stenting or subcutaneous ureteral bypass
PHYSICAL EXAM FINDINGS
• Unilateral or bilateral renal enlargement • Allows FNA if suspicious for neoplasia is recommended for ureteral obstruction.
This should be considered an emergency
• Allows aspiration of perinephric pseudocysts
• May be painful on renal palpation (if acute) to temporarily relieve pressure on renal (p. 1008).
• Dehydration if anorexic or vomiting parenchyma • Massive renomegaly is often associated with
Urine culture and sensitivity: renal cysts or pseudocysts and occasionally
Etiology and Pathophysiology • Warranted if suspicion of pyelonephritis, with hydronephrosis or neoplasia.
• Polycystic kidney disease (cats) (p. 805) even if urine sediment benign
• Neoplasia (bilateral or unilateral): lymphoma, Abdominal radiographs: Prevention
renal carcinoma (p. 876) • Confirm renomegaly Genetic testing for polycystic kidney disease in
• Hydronephrosis due to obstruction: uretero- • Identify uroliths; most nephroliths/uretero- breeding cats (especially Persians, Himalayans,
lith, stenosis, trauma, neoplasia (p. 483) liths are radiopaque calcium oxalate and British shorthairs)
• Perirenal pseudocysts Blood pressure: systemic hypertension can be
• Amyloidosis (p. 51) a complication of renal disease Technician Tips
• AKI • Blood pressure measurement is a core vital
• Infection: feline infectious peritonitis (FIP), Advanced or Confirmatory Testing sign in any patient with renal disease.
leptospirosis (dogs), pyelonephritis, abscess FNA and cytology of kidneys: • Obtaining blood pressures on young to
• Secondary hypertrophy (mild enlargement): • Often diagnostic for neoplasia (especially middle-aged animals during wellness visits
absence or damage of other kidney, porto- lymphoma) allows doctors to have a baseline for com-
systemic shunt • Can be used for culture (nephritis, parison and can help differentiate anxiety
pyelonephritis) from true hypertension. Record position of
DIAGNOSIS Thoracic radiographs: the animal (lateral, sternal), the leg used, and
• Rule out metastatic neoplasia. the cuff size so that future measurements are
Diagnostic Overview • Evaluate cardiac size in patients that may done the same way.
Minimum database should include CBC, need aggressive fluid therapy.
chemistry panel, and urinalysis to assess Ethylene glycol testing, urine or serum (p. 314) SUGGESTED READING
renal function, and abdominal ultrasound. Serologic or polymerase chain reaction (PCR) Berent AC: Ureteral obstructions in dogs and cats:
Ultrasound is more valuable than abdominal testing for leptospirosis (p. 583) a review of traditional and new interventional
radiographs because it allows direct visualization Renal biopsy: not recommended if creatinine diagnostic and therapeutic options. J Vet Emerg
of the kidneys and can narrow the differential > 5.0 mg/dL or bleeding disorder Crit Care 21:86-103, 2011.
list quickly. Ultrasound also allows fine-needle
aspiration (FNA) of masses or drainage of TREATMENT ADDITIONAL SUGGESTED
perinephric pseudocysts. READINGS
Treatment Overview Bonazzi, M, et al: Comparison between ultrasound
Differential Diagnosis Depends on underlying cause (see chapters on and genetic testing for the early diagnosis of poly-
• Other organ enlargement specific disorders) cystic kidney disease in Persian and Exotic Shorthair
• Other abdominal mass cats. J Feline Med Surg 11:430-434, 2009.
• Retroperitoneal bleeding or mass Acute General Treatment Bua AS, et al: Respective associations between ureteral
• AKI is always an emergency (p. 23) obstruction and renomegaly, urine specific gravity,
Initial Database • Ureteral obstruction is an emergency because and serum creatinine concentration in cats: 29 cases
CBC (may be unremarkable): hydronephrosis significantly decreases renal (2006–2013). J Am Vet Med Assoc 247:518-524,
2015.
• Anemia: CKD, anemia of chronic disease function (p. 1008). Monteiro SC, et al: Ultrasound in the diagnosis of
• Erythrocytosis: ± renal neoplasia renomegaly in small animals-literature review. Clín
• Elevated white blood cell count: infection, Nutrition/Diet Vet 14:54-58. 2009.
inflammation, neoplasia (usually no blasts Diets specially formulated for animals with Sohn J, et al: Reestablishment of radiographic kidney
in blood with renal lymphoma) renal dysfunction may be indicated (p. 169). size in miniature schnauzer dogs. J Veter Med Sci
• Thrombocytopenia: infection, severe 78:1805-1810, 2016.
inflammation Possible Complications Taylor AJ, et al: Ultrasonographic characteristics of
Chemistry panel (may be unremarkable): Hemorrhage after renal FNA or biopsy canine renal lymphoma. Vet Radiol Ultrasound
55:441-446, 2014.
• Azotemia: elevated creatinine, blood urea Tripathi R, et al: Diagnosis of renal disorders in dogs
nitrogen (BUN), symmetric dimethylarginine PROGNOSIS & OUTCOME using ultrasound technique. Vet. Radiol Ultrasound
(SDMA) test, phosphorous 33:292-296, 2010.
• May have concurrent liver enzyme elevation Depends on causes; can be benign or associated
with leptospirosis with life-limiting disease RELATED CLIENT EDUCATION
Urinalysis (may be unremarkable):
• Isosthenuria: CKD or AKI PEARLS & CONSIDERATIONS SHEETS
• The pH or crystals may help with determina- Consent to Perform Abdominal Ultrasound
tion of urolith type. Comments Consent to Perform Cystocentesis
• Bacteruria: pyelonephritis cannot be ruled • Ultrasound is a vital diagnostic tool for Consent to Perform Fine-Needle Aspiration
out by absence of bacteruria. renomegaly and should be employed as an of Masses
Abdominal ultrasound: initial test. How to Collect a Urine Sample
• Often diagnostic (e.g., perinephric pseudo- • When the kidneys are different sizes on
cyst, polycystic kidney, hydronephrosis) palpation, it may be difficult to determine AUTHOR: Claire M. Weigand, DVM, DACVIM
EDITOR: Leah A. Cohn, DVM, PhD, DACVIM

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