Critical care of the small rodent: a veterinary nurse's guide

Registered veterinary nurses (RVNs) should have a basic understanding of the general small rodent anatomical and behavioural characteristics in order to identify compromised patients and contribute to emergency and critical care nursing plans (Table 1). For the purposes of this article the term ‘small rodent’ will refer to rodents below 500 g bodyweight (BW) and encompass the most commonly kept species, e.g. rat (Rattus norvegicus), mouse (Mus musculus), degu (Octodon spp.), gerbil (Meriones unguiculatus), and hamster (Syrian, Mesocricetus auratus; Siberian, Phodopus sungorus; Chinese, Cricetulus griseus).

In general small rodents are relatively short lived, 2–4 years, although longer in the degu (7 years) and the effects of ageing may predispose individuals to critical conditions (O'Malley, 2005; Table 1). Their small body size can not only pose a challenge when handling and applying treatments, but also in ensuring their high metabolic demands are met, e.g. they are prone to hypoglycaemia following periods of anorexia. This high metabolism and small body mass to body surface ratio, also increases their sensitivity to environmental temperature fluctuations, e.g. hypothermia or hyperthermia. It is well documented in the literature that rodents exhibit typical ‘prey-like’ attributes and respond to olfactory cues from potential threats (e.g. dogs, cats, humans), which predisposes them to stresses faced in a veterinary hospital (Ferrero et al, 2011). This is an innate response necessary for survival (Bradley Bays, 2006). Predator avoidance strategies, coupled with the potential for a poor appreciation or late detection of an illness by the owner, often results in rodents presented to veterinary staff in a critically ill state.