C-terminal telopeptide of type I collagen, osteocalcin, alkaline phosphatase, and parathyroid hormone in healthy and hospitalized foals.

Hypocalcemia is a common finding in critically ill equine patients. Parathyroid hormone (PTH) helps to maintain calcium homeostasis in hypocalcemic patients by promoting renal calcium reabsorption and bone resorption. Increased serum PTH concentrations have been reported in critically ill people and animals, including horses and foals. It is unknown whether increased secretion of PTH is associated with markers of bone turnover in hospitalized foals. The goals of this study were to measure markers of bone resorption (C-terminal telopeptide of type I collagen [CTX-I]) and bone formation (osteocalcin [OCN]; alkaline phosphatase [ALP]) and to determine their association with PTH concentrations, disease severity, and mortality in hospitalized foals. This prospective, multicenter, cross-sectional study was conducted on 75 newborn foals ≤3 d old divided into hospitalized (n = 65; 41 septic; 24 sick nonseptic) and healthy (n = 10) groups. Blood samples were collected on admission to measure serum CTX-I, OCN, and PTH concentrations and ALP activity. Data were analyzed by nonparametric methods and univariate logistic regression. Serum CTX-I and PTH concentrations were significantly higher, whereas OCN concentrations were lower, in septic compared with healthy foals (P < 0.05). Serum ALP activity was not different between groups; however, it was lower in hospitalized and septic foals with low OCN concentrations (P < 0.05). In hospitalized foals, PTH concentrations were positively correlated with CTX-I concentrations and inversely associated with ALP activity (P < 0.05). High CTX-I and low OCN concentrations were associated with disease severity (P < 0.05). Hospitalized nonsurviving foals had significantly lower OCN concentrations compared with survivors (P < 0.05), but CTX-I concentrations were not associated with survival. Hospitalized foals with PTH concentrations >12.4 pmol/L were more likely to die (OR = 1.5; 95% CI = 1.1-4.16; P < 0.05). Elevated PTH and CTX-I together with reduced OCN concentrations and ALP activity in sick foals indicates that bone resorption is increased during critical illness, which may be a compensatory mechanism to correct hypocalcemia or reflect a response to systemic inflammation and metabolic imbalances. Bone resorption could negatively impact skeletal development in the growing foal. Low OCN and high PTH concentrations were predictors of nonsurvival in hospitalized foals.

Atrial Fibrillation in Eight New World Camelids.

BACKGROUND: There is limited information on the incidence of clinical signs, concurrent illness and treatment options for atrial fibrillation (AF) in New World Camelids (NWC). OBJECTIVE: Describe clinical signs and outcome of AF in NWC. ANIMALS: Eight New World Camelids admitted with AF. METHODS: A retrospective observational study of camelids diagnosed with AF based on characteristic findings on electrocardiogram (ECG). RESULTS: All animals had an irregularly irregular heart rhythm detected on physical examination and 4 cases had obtunded mentation on admission. Three camelids were diagnosed with AF secondary to oleander intoxication, 3 animals had underlying cardiovascular disease, 1 was diagnosed with lone AF and 1 had AF diagnosed on examination for a urethral obstruction. Five of eight animals survived to discharge and nonsurvivors consisted of animals which died or were euthanized as a result of cardiovascular disease (2/8) or extra-cardiac disease unrelated to the AF (1/8). CONCLUSIONS AND CLINICAL IMPORTANCE: Atrial fibrillation occurs in NWC in association with cardiovascular disease, extra-cardiac disease or as lone AF. Amiodarone and transthoracic cardioversion were attempted in one llama with lone AF, but were unsuccessful. Atrial fibrillation was recorded in 0.1% of admissions.