Cutaneous and renal glomerular vasculopathy as a cause of acute kidney injury in dogs in the UK

Abstract

To describe the signalment, clinicopathological findings and outcome in dogs presenting with acute kidney injury (AKI) and skin lesions between November 2012 and March 2014, in whom cutaneous and renal glomerular vasculopathy (CRGV) was suspected and renal thrombotic microangiopathy (TMA) was histopathologically confirmed. The medical records of dogs with skin lesions and AKI, with histopathologically confirmed renal TMA, were retrospectively reviewed. Thirty dogs from across the UK were identified with clinicopathological findings compatible with CRGV. These findings included the following: skin lesions, predominantly affecting the distal extremities; AKI; and variably, anaemia, thrombocytopaenia and hyperbilirubinaemia. Known causes of AKI were excluded. The major renal histopathological finding was TMA. All thirty dogs died or were euthanised. Shiga toxin was not identified in the kidneys of affected dogs. Escherichia coli genes encoding shiga toxin were not identified in faeces from affected dogs. CRGV has previously been reported in greyhounds in the USA, a greyhound in the UK, without renal involvement, and a Great Dane in Germany. This is the first report of a series of non-greyhound dogs with CRGV and AKI in the UK. CRGV is a disease of unknown aetiology carrying a poor prognosis when azotaemia develops.

Keywords: Dermatopathology; Histopathology; Internal medicine; Kidneys; Renal disease; Skin.

FIG 1:

Map to show distribution of where confirmed cases lived. (Zoomed in view shows distribution of cases in the South of England as there were proportionally more cases from this area)

FIG 2:

All images are photographs of lesions affecting confirmed cases. (a) Superficial ulcer affecting medial thigh. (b) Deep ulceration, erythema and exudation on a digit. (c) Erosion to carpal pad, before cleaning. (d) The same lesion after clipping and cleaning

FIG 3:

(a) Tongue lesions. (b) Tongue ulcer

FIG 4:

Photomicrographs of a glomerulus and an intralobular artery from a dog with CRGV, stained with haematoxylin and eosin [H&E] (a and c) and Masson's trichrome (b and d). There is fibrinoid vascular necrosis (asterisks) of intralobular arteries and arterioles. Glomerular capillaries are severely distended and contain red blood cells, many of which are fragmented. Distension of glomerular capillaries is due to dissolution of the mesangial matrix (mesangiolysis). Tubules are undergoing degeneration and necrosis; most tubules contain protein casts whereas some contain red blood cell casts.

FIG 5:

Photomicrograph of a necrotic hair follicle with neutrophilic infiltrates

FIG 6:

Photomicrograph of a small dermal artery with fibrinoid necrosis of the vessel wall

FIG 7:

Electron micrograph of a glomerular capillary loop from a dog with cutaneous and renal glomerular vasculopathy (CRGV). There are multiple deformed red blood cells (white asterisks) and swollen endothelial cells (black asterisks). A few small aggregates of fibrin tactoids are present at the periphery of the capillary loop (arrows)