Felis ISSN 2398-2950

Glomerulonephritis

Synonym(s): GN

Contributor(s): Richard Squires, Melissa Wallace, Penny Watson

Introduction

  • Cause: deposition orin situ formation of antigen-antibody complexes in the basement membranes of glomerular capillaries in the kidneys. 
  • Signs: ususally no clinical signs until advanced. Proteinuria leads to hypoalbuminemia and sometimes to ascites or edema. Severe glomerular damage leads to loss of nephrons and eventually to renal failure (causing polydipsia/polyuria, inappetence, vomiting).
  • Diagnosis: urine analysis, serum chemistry profile, histopathologic examination of kidney biopsy.
  • Treatment: detect and eliminate the underlying source of antigen, if possible. Special diet, angiotensin-converting enzyme (ACE) inhibition, +/- low-dose aspirin (with great care), +/- immunosuppressant/immunomodulator therapy.
  • Prognosis: variable. Some cases progress rapidly despite therapy, others remain stable for prolonged periods. Many undetected cases probably go on to develop renal failure and are diagnosed at that stage. If complicated by thromboembolism, eg pulmonary or caudal aortic, prognosis is poor.

Pathogenesis

Etiology

Predisposing factors

General

  • An inflammtory, infectious, or neoplastic source of antigens that can contribute to immune complex formation.
  • A familial predisposition to form immune complexes in the glomeruli (not confirmed in cats).
  • Altered, ie increased, intestinal permeability may allow entry of antigens and play a role in some cats.

Pathophysiology

  • Antigen-antibody (Ag-Ab) complexes deposit or form at the glomerulus capillary basment membranes    →     complement activation   →   cell membrane damage   →   leukocyte attraction and platelet aggregation    →   glomerular injury   →    leakage of proteins, especially albumin, through the glomerular filter   →    proteinuria   →    (if severe) hypoalbuminemia Hypoproteinemia, weight loss, ascites, peripheral edema and hypercholesterolemia.
  • Cellular proliferation, mesangial cell contraction and glomerular obliteration   →   decreased glomerular filtration through affected glomeruli   →   increased glomerular filtration through other, less damaged nephrons   →   'hyperfiltration' and glomerulosclerosis of remaining nephrons   →   (if sufficiently severe) chronic renal failure.
  • Loss of antithrombin III, platelet hyperactivity, and (sometimes) thrombocytosis     →   hypercoagulable state   →    thromboembolic disorders (lungs, caudal aorta).

Timecourse

  • Variable. Disease may progress rapidly or remain stable for years.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Grauer G F (2007) Measurement, interpretation, and implications of proteinuria and albuminuria. Vet Clin North Am Sm Anim Pract 37 (2), 283-295 PubMed.
  • Elliott J & Syme H M (2006) Proteinuria in chronic kidney disease in cats-prognostic marker or therapeutic target? J Vet Intern Med 20 (5), 1052-1053 PubMed.
  • Kuwahara Y, Ohba Y, Kitoh K et al (2006) Association of laboratory data and death within one month in cats with chronic renal failure. JSAP 47 (8), 446-450 PubMed.
  • Langston C E & Reine N J (2006) Hyperthyroidism and the kidney. Clinical techniques in Small Animal Practice 21 (1), 17-21 PubMed.
  • Mardell E J & Sparkes A H (2006) Evaluation of a commercial in-house test kit for the semi-quantitative assessment of microalbuminemia in cats. J Fel Med Surg (4), 269-278 PubMed.
  • Syme H M, Markwell P J, Pfeiffer D et al (2006) Survival of cats with naturally occurring chronic renal failure is related to severity of proteinuria. J Vet Intern Med 20 (3), 528-535 PubMed.
  • Welles E G, Whatley E M, Hall A S et al (2006) Comparison of Multistix PRO dipsticks with other biochemical assays for determining urine protein (UP), urine creatinine (UC) and UP:UC ratio in dogs and cats. Vet Clin Pathol 35 (1), 31-36 PubMed.
  • White J D, Norris J M, Baral R M et al (2006) Naturally-occurring chronic renal disease in Australian cats: a prospective study of 184 cases. Aust Vet J 84 (6), 188-194 PubMed.
  • Lees G E, Brown S A, Elliott J et al (2005) Assessment and management of proteinuria in dogs and cats: 2004 ACVIM Forum Consensus Statement (small animal). J Vet Intern Med 19 (3), 377-385 PubMed.
  • Lees G E (2004) Early diagnosis of renal disease and renal failure. Vet Clin North Am Sm Anim Pract 34 (4), 867-885 PubMed.
  • Osbourne C A, Bartges J W, Polzin D J et al (1996) Percutaneous needle biopsy of the kidney. Inidcations, applications, technique, and complications. Vet Clin North Am Sm Anim Pract 26 (6), 1461-1504 PubMed.
  • Arthur J E, Lucke V M, Newby T J et al (1986) The long term prognosis of feline idiopathic membranous glomerulonephritis. JAAHA 22 (6), 731-737 VetMedResource.
  • Nash A S, Wright N G, Spencer A J et al (1979) Membranous nephropathy in the cat: a clinical and pathological study. Vet Rec 105 (4), 71-77 PubMed.


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