Distal limb cryotherapy for the prevention of acute laminitis

A review of recent developments in the pharmacological prevention and treatment of endocrinopathic laminitis

“…However, Pollitt has argued strongly against the hypoperfusion theory, stating that laminitis does not occur if the foot is in a state of vasoconstriction during the developmental phase (Pollitt 2004). This theory is also difficult to reconcile with the efficacy of cryotherapy as a treatment for the condition (van Eps et al 2004). Instead, Pollitt argued that laminitis development coincides with an increase in sublamellar blood flow (Pollitt and Davies 1998), and this is certainly consistent with observations of an increase in hoof wall surface temperature during the developmental phase of laminitis in horses infused with insulin (de Laat et al 2012).…”

A comparison of seven methods for continuous therapeutic cooling of the equine digit

“…There have been no published studies comparing HWST with internal hoof temperature or actual lamellar temperature; however, in a study where surface temperature was measured [4] the mean HWST was only 1°C greater than that measured deep in the stratum medium in another study [1] which used an identical limb cooling method. The benefits of therapeutic hypothermia in the prevention and early treatment of acute laminitis in horses are well established in experimental models and now also in naturally occurring disease [1][2][3][4][5][6][7][8]; however, it is unclear what tissue temperature is actually required for an effect. As the mean HWST of the uncooled foot was approximately 30°C in the current study as well as in previously reported experimental conditions [5], the empirically recommended target HWST of <10°C represents a decrease of at least 20°C below normal HWST and approximately 27°C below the normal equine core body temperature.…”

“…Although an effective clinical temperature range has not been established, experimental studies have consistently demonstrated a therapeutic and prophylactic effect when either mean hoof internal or surface temperature has been reported in a range from 3.5 to 7.1°C [1][2][3][4][5][6]. For clinical use, it has been recommended (based on these results) that hoof temperature should be maintained at <10°C with the goal of targeting the experimental study temperatures reported in the literature, since the efficacy of less profound cooling has not been evaluated [8]. The goal of this study was to obtain data on the hoof temperatures achieved using several methods that are currently used in clinical practice for cooling the equine distal limb and also to evaluate a prototypical dry-sleeve cooling device.…”

The management of equine acute laminitis

“…Continuous application of cryotherapy (maintaining hoof wall surface temperature at 5°C–7°C) to the distal aspect of limbs for 48 hours prevents lameness, improves epidermal laminar histologic scores, reduces expression of messenger RNA for matrix metalloproteinase 2 (MMP-2), and reduces lamellar inflammatory signaling in horses with carbohydrate overload-induced laminitis. 11 – 17 In the only clinical study of cryotherapy for laminitis prophylaxis, Kullman et al found that horses with colitis were ten times less likely to develop laminitis when the limbs were cooled continuously for 48 hours or more. 18 This treatment is generally well tolerated by horses; however, it requires intensive management, replacing ice every 1–2 hours to have a constant ice slurry capable of keeping the hoof wall surface temperature below 10°C, as recommended.…”

“… 18 This treatment is generally well tolerated by horses; however, it requires intensive management, replacing ice every 1–2 hours to have a constant ice slurry capable of keeping the hoof wall surface temperature below 10°C, as recommended. 17 Methods that incorporate the hoof, pastern, fetlock, and a portion of the cannon bone while still allowing some freedom of movement are needed for optimal hoof cooling. The most effective cooling methods are either 63 cm tall vinyl boots containing ice and water or a circulating refrigerated bath.…”