Page 146 - Cote clinical veterinary advisor dogs and cats 4th

52 Amyloidosis

• Immunoglobulin light chain–associated ○ Amyloid deposition in Chinese Shar-peis Nutrition/Diet
amyloidosis is rare. and Abyssinian cats may be limited to the Renal diets are appropriate for affected animals.
VetBooks.ir lymphomas, and plasma cell tumors diagnostic (renal biopsies should contain Recommended Monitoring
renal medulla, and biopsy may not be
○ Associated with multiple myeloma, some
UPC ratio, urinalysis, serum albumin and
only cortex).
DIAGNOSIS
○ Because other organs can be affected,
biopsy can confirm amyloid outside of creatinine, blood pressure, body weight, and
body condition score should be monitored
Diagnostic Overview the kidney. Hepatic biopsy may be pre- weekly to monthly initially. After patients are
Definitive diagnosis of amyloidosis requires ferred when there is clinicopathologic stable, recheck every 3-6 months unless therapy
biopsy of an affected organ (usually kidney). evidence of liver dysfunction. or condition changes.
Presumptive diagnosis is appropriate for Chinese • Additional testing may be indicated to
Shar-peis with history of fever and/or joint identify underlying inflammatory/infectious/ PROGNOSIS & OUTCOME
pain. neoplastic disease.
• Guarded to grave despite treatment. Median
Differential Diagnosis TREATMENT survival of dogs with renal amyloidosis is 5
• Proteinuria: see p. 1272. days from time of diagnosis, with only 20%
• Other differential diagnoses depend on organ Treatment Overview of dogs surviving ≥ 30 days.
involvement (e.g., hepatomegaly [p. 456]). Prognosis is guarded to poor unless an underly- ○ Survival is negatively associated with serum
ing disease is identified and corrected. Non- creatinine concentration. Azotemic dogs
Initial Database specific therapies include reduction of often rapidly progress to uremic crisis.
• CBC: unremarkable or reflective of underly- proteinuria and treatment of renal failure and • Prognosis may be improved (with occasional
ing inflammatory process its consequences. Efficacy of specific treatments reported resolution) if concurrent diseases
• Chemistry profile: unremarkable or reflective for amyloidosis is unknown. are identified and successfully treated.
of underlying disease until amyloidosis is • Early colchicine therapy (before onset of
advanced. Most dogs with renal amyloidosis Acute General Treatment renal failure) for Chinese Shar-pei dogs can
eventually develop hypoalbuminemia and • Stabilization and treatment of uremic crisis greatly improve prognosis.
may develop findings typical of nephrotic if present
syndrome (p. 691) and/or CKD (pp. 167 • General therapy for PLN: see Glomerulo- PEARLS & CONSIDERATIONS
and 169). Azotemia can occur without nephritis (p. 390)
proteinuria in Chinese Shar-pei dogs and • Treatment of complications: see Acute Kidney Comments
cats. Chinese Shar-pei dogs are less likely to Injury (p. 23); Chronic Kidney Disease, • Differentiation of amyloidosis from other
develop nephrotic syndrome than dogs with Occult (p. 167); Chronic Kidney Disease, causes of PLN requires biopsy. Histologic
reactive amyloidosis and are more likely to Overt (p. 169); Nephrotic Syndrome (p. diagnosis allows tailored therapy and
be azotemic at time of diagnosis. 691); Pulmonary Thromboembolism (p. prognosis.
• Urinalysis: proteinuria secondary to glomeru- 842); Systemic Hypertension (p. 501) • Amyloidosis is primarily a renal cortical
lar amyloid deposition. Ability to concentrate • Acute hemoabdomen (p. 430) in cats with disease in dogs other than Chinese Shar-peis.
urine is compromised as kidney damage hepatic rupture requires abdominal explor- • Chinese Shar-peis with consistent clinical
progresses. atory and supportive care (e.g., transfusion). signs (recurrent lameness and fever with or
• Arterial blood pressure: systemic hypertension without proteinuria and azotemia) can be
common Chronic Treatment presumptively diagnosed with amyloidosis
• Urine protein/creatinine (UPC) ratio: often • Management/resolution of any concurrent even without biopsy.
dramatically increased in non–Chinese inflammatory diseases • Substantial amyloid deposition may be
Shar-pei dogs; variably increased in Chinese • Continued management of PLN and chronic present despite normal blood urea nitrogen,
Shar-peis and cats kidney disease creatinine, and urine-specific gravity values.
• Imaging: kidneys and liver may be mildly • Dimethyl sulfoxide may slow or prevent
enlarged and hyperechoic on ultrasono- progression of amyloidosis: 300 mg/kg PO Prevention
graphic examination. Rarely, hemoabdomen q 24h, or dilute 90% solution 1 : 4 in sterile Affected animals should not be bred.
and hepatic fracture identified in Oriental water and administer 20-80 mg/kg SQ 3
cats with hepatic amyloid deposition. times/week. Owners should wear gloves when SUGGESTED READING
administering. SQ injections may cause local Segev G, et al: Renal amyloidosis in dogs: a retrospec-
Advanced or Confirmatory Testing irritation. Treatment is lifelong. tive study of 91 cases with comparison of the disease
• Biopsy is required for definitive diagnosis. • Colchicine should be administered to between shar-pei and non-shar-pei dogs. J Vet
Histologic findings: Chinese Shar-peis at earliest diagnosis, Intern Med 26:259-268, 2012.
○ Hematoxylin and eosin stain: homo- regardless of disease severity or presence of AUTHOR: Barrak M. Pressler, DVM, PhD, DACVIM;
geneous eosinophilic material within proteinuria: 0.01-0.03 mg/kg PO q 24h. If Leah A. Cohn, DVM, PhD, DACVIM
affected organs, particularly the glomerular vomiting/diarrhea develop, decrease dose EDITOR: Leah A. Cohn, DVM, PhD, DACVIM
mesangium temporarily. Treatment is lifelong.
○ Congo red stain: apple-green birefringence • Prednisone and other antiinflammatory
when viewed under polarized light medications are of no known benefit.

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