Haemolytic anaemia and acute pancreatitis associated with zinc toxicosis in a dog

Abstract

We describe a case of zinc toxicity in a 14-month-old, female, neutered, Cavalier King Charles spaniel with a 48-hour history of haematochezia, icterus and collapse. Regenerative anaemia with a packed-cell volume of 7 per cent was seen. Prior to referral, radiography had revealed a gastric, metallic foreign body which was removed at exploratory laparotomy. On presentation, the dog was comatose, hypothermic and bradycardic - resuscitation was performed successfully, but the dog then displayed marked abdominal pain. The dog died 12 hours after presentation. At postmortem examination, the animal showed severe icterus. Both kidneys were diffusely dark red; the pancreas was diffusely pale and nodular. Histopathological examination revealed evidence of intravascular haemolysis with blood vessel lumens containing haemoglobin. The renal tubules also contained large amounts of intraluminal haemoglobin with haemoglobin crystals scattered throughout the cortex and medulla. The pancreas exhibited multifocal coagulative necrosis, surrounded by a neutrophil-dominated inflammatory infiltrate. Zinc levels were markedly increased above the normal reference range in both liver and kidney. This report describes the clinical and pathological findings of a case of acute zinc toxicity in a dog following ingestion of a metallic object which resulted in marked haemolytic anaemia and acute pancreatitis.

Treatment of zinc toxicosis in a dog with chelation using d‐penicillamine

“…Generally, the removal of the zinc source and supportive therapy suffice as treatment for zinc toxicosis without chelation therapy . However, several case reports have described complications of zinc toxicosis that have occurred after removal of the zinc source, some of which have been fatal or caused severe complications with delayed recovery . Clinical signs and hemogram values in this case worsened for 50 hours after removal of the foreign body.…”

“…Hypotheses include a direct toxic effect of the metal on RBC membranes or a predisposition to oxidative injury due to impaired protective enzyme systems . The formation of Heinz bodies in zinc toxicosis supports the theory of oxidative damage; however, in a retrospective study of 19 dogs with zinc toxicosis, only 33% of cases had Heinz bodies, which indicates that oxidative injury may not be solely responsible for the hemolysis . Complications of zinc toxicosis include hemolytic anemia, pancreatitis, anuric acute renal failure, renal tubular injury, gastrointestinal disturbance, and death …”

“…Zinc toxicosis has been commonly reported in small animals due to ingestion of US pennies, which are made of zinc alloy . Following ingestion, zinc is released due to low gastric pH to produce soluble zinc salts, which are then absorbed through the small intestine .…”

Crystal structure of active site mutant of antileukemic l‐asparaginase reveals conserved zinc‐binding site

“…However, the pancreas is critically dependent on zinc homeostasis; it stores zinc concentrated in islet cells and uses it to secrete zinc‐loaded insulin . A disturbed balance of ‘bound’ versus ‘free’ zinc can result in pancreatitis . Another common side effect of l ‐asparaginase therapy is thrombosis , which is also critically dependent on zinc homeostasis .…”

Foreign Body Gastrotomy in an Adult Captive Cheetah, Acinonyx jubatus

“…These studies contradict those by Hayes (2009), who had earlier reported that animals with linear foreign bodies showed more severe clinical signs and gastrointestinal pathology than animals with discreet foreign bodies. Diagnosis of foreign bodies can be done by careful history taking (Hoefer and Levitan, 2013), physical examination (palpation), plain radiography, contrast radiography, ultrasonography (Boag et al, 2005), computed tomography (Williams et al, 2013), clinical pathology (Blundell and Adam, 2013), and exploratory coeliotomy (Papazoglou et al, 2010). The pathology associated with the foreign bodies varies according to time lapse since lodgement, the location, the nature, shape and size (Tyrrell and Beck, 2006) and solubility of the material and the degree of obstruction caused by the foreign body (Fazio, 2006).…”