Contributors: Phil Nicholls, Julien Bazelle

 Species: Canine   |   Classification: Diseases

Introduction Pathogenesis Diagnosis Treatment Outcomes Further Reading

Introduction

  • Cause: juvenile renal disease is usually caused by a congenital (developmental) or hereditary renal abnormality.
  • The diseases include renal dysplasia, renal agenesis, renal cortical hypoplasia, glomerulopathies or reflux nephropathy with segmental hypoplasia (Ask-Upmark kidney).
  • Signs: the animals present with signs of chronic renal failure, stunted growth, dysphagia, signs related to renal secondary hyperparathyroidism.
  • Diagnosis: history, clinical signs, biochemistry, hematology, blood pressure, urinalysis, radiography, ultrasonography, histopathology.
  • Prognosis: guarded.

Presenting Signs

Age Predisposition

  • <1 year old (<7 months).
  • Severely affected animals die young.

Breed Predisposition

Special Risks

Pathogenesis

Etiology

  • Not well-defined.
  • Insults during the fetal and neonatal period, eg:
  • Hereditary:
    • A familial basis has not been established in all cases.
    • Hereditary nephropathy: abnormalities of type IV collagen genes. 
    • An autosomal recessive mode of inheritance is probable in Lhasa Apso Lhasa Apso and Shih Tzu Shih Tzu breeds.
    • Familial disease has been reported in Soft-coated Wheaten Terrier Soft Coated Wheaten Terrier , Standard Poodle Poodle: Standard , Chow Chow Chow Chow , Alaskan Malamute Alaskan Malamute , Golden Retriever Retriever: Golden and Dutch Kooiker Kooikerhondje.
    • But the disease has been reported in many other breeds also, for which a familial basis has not been shown.
  • Same as chronic renal failure (less common in young dog)

Predisposing Factors

General

  • Breed.

Pathophysiology

  • Renal disease in immature or young adult dogs which is not associated with primary renal inflammation:
    • Agenesis.
    • Hypoplasia.
    • Dysplasia.
    • Primary cystic diseases.
    • Glomerulopathies.
    • Tubulointerstitial nephropathies.
    • Tubular transport dysfunction.
  • Renal dysplasia is characterized by disorganized development of renal parenchyma due to anomalous differentiation.
  • Induction of the metanephric blastema is initiated but fails to undergo complete differentiation → persistence of poorly differentiated tissue, ie fetal glomeruli and/or tubules, persistent mesenchyme, or anomalous structures, ie atypical tubular epithelium.
  • Persistent metanephric ducts and dysontogenic metaplasia - rare in dogs.
  • Due to agenesis, developmental abnormalities and non-functioning renal tissue signs of chronic renal failure usually develop before the animal is one year old.
  • Increased renal calcium loss → hyperparathyroidism → osteoporosis → increased risk of fibrous osteodystrophy (rubber jaw) and fractures.

Timecourse

  • Once clinical signs develop, the disease progresses rapidly.

Diagnosis

Presenting Problems

Client History

  • Stunted growth.
  • Same as chronic renal failure Kidney: chronic kidney disease (CKD):
    • Polyuria/polydipsia. 
    • Weight loss/poor weight gain. 
    • Inappetence. 
    • Vomiting/diarrhea. 
    • Depression. 
  • Difficulty eating (rubber jaw).

Clinical Signs

  • Rubber jaw.

Diagnostic Investigation

Biochemistry, hematology, blood gas  

Radiography

  • Kidneys may be small and misshapen.
  • Osteoporosis, paper thin cortices, especially visible on skull radiography.
  • Fractures.

2D Ultrasonography

  • Renal architecture may be abnormal, generally with changes in echogenicity, irregular margins Ultrasonography: kidney.
  • Increased resistive index . 

Urinalysis

Gross Autopsy Findings

  • Chronic renal failure and uremia in a young dog.
  • There may be rubber jaw (flexibility of mandibles and other skull components).
  • Affected kidneys may be shrunken, pale, firm, with a stippled cortex.
  • There may be cortical scars, medullary fibrosis and cysts.

Histopathology Findings

  • Depending on the type, there can be membranoproliferative glomerulonephritis, thickening of Bowman's capsule, periglomerular fibrosis, tubular atrophy and cyst formation.
  • Interstitial fibrosis may be seen.

Differential Diagnosis

  • Hypothyroidism (stunted growth) Hypothyroidism.
  • Congenital dwarfism (decreased growth hormone).
  • Hypophosphatemic rickets (stunted growth, decreased opacity skeleton).
  • Congenital porto-systemic shunt (polyuria/polydipsia, stunted growth  Congenital portosytemic shunt (CPSS).

Treatment

Standard Treatment

Outcomes

Prognosis

Good

  • If enough normal functioning renal tissue is present, eg in agenesis of one kidney.
  • Renal telangiectasia may only develop problems quite late in life.
  • Some Shih Tzu have lived several years before developing clinical signs.

Poor

  • Once renal failure develops, disease usually progresses quite rapidly.
  • Mean age at death is 2 years or less.

Expected Response to Treatment

  • Stabilizing azotemia and general demeanor of the animal.

Reasons for Treatment Failure

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Fyfe J C, Hemker S L, Venta P J, Stebbing B, Giger U (2014) Selective intestinal cobalamin malabsorption with proteinuria (Imerslund-Gräsbeck syndrome) in juvenile Beagles. J Vet Intern Med 28(2), 356-362 PubMed.  
  • Brachthäuser L, Pingen C H, Hecht W, Reinacher M (2013) Rubber jaw in a Weimaraner dog due to juvenile nephropathy. A case without evidence for genetic involvement. Tierarztl Prax Ausg K Kleintiere Heimtiere 41(3), 198-202 PubMed.  
  • Fyfe J C, Hemker S L, Venta P J, Fitzgerald C A, Outerbridge C A, Myers  SL, Giger U (2013) An exon 53 frameshift mutation in CUBN abrogates cubam function and causes Imerslund-Gräsbeck syndrome in dogs. Mol Genet Metab109(4), 390-396 PubMed. 
  • Lees G E (2013) Kidney diseases caused by glomerular basement membrane type IV collagen defects in dogs. J Vet Emerg Crit Care (San Antonio) 23(2), 184-193 PubMed. 
  • Kolbjørnsen O, Heggelund M, Jansen J H (2008) End-stage kidney disease probably due to reflux nephropathy with segmental hypoplasia (Ask-Upmark kidney) in young Boxer dogs in Norway. A retrospective study. Vet Pathol 45(4), 467-474 PubMed.
  • Peeters D et al (2000) Juvenile nephropathy in a Boxer, a Rottweiler, a Collie and an Irish Wolfhound. Aust Vet J 78 (3), 162-165 PubMed.

Other Sources of Information