Prevalence and types of hyponatraemia, its relationship with hyperglycaemia and mortality in ill pet rabbits

Abstract

Prevalence of hyponatraemia has not been extensively studied in pet rabbits, and the reference data for calculated plasma tonicity and osmolarity are not available. This retrospective clinical study reports the prevalence of hyponatraemia, hyposmolarity and hypotonicity in ill pet rabbits (n=356). The relationship between sodium and glucose levels was studied (n=134). Mortality rates within seven days associated with different sodium levels were calculated in ill rabbits (n=322). Venous blood samples in lithium heparin were processed using iStat EC8+ cartridges. The 95% RI for plasma sodium, calculated osmolarity and tonicity from 51 healthy pet rabbits were 136-147 mEq/l, 284-312 mOsm/l and 278-302 mOsm/l, respectively. The prevalence of hyponatraemia, hypotonicity and hyposmolarity was 39.0 per cent, 28.7 per cent and 18.0 per cent, respectively. Pseudohyponatraemia was present in 28.1 per cent and true hyponatraemia was present in 71.9 per cent of the cases of hyponatraemia. Sodium levels less than 129 mEq/l were found to be associated with 2.3-fold increase in mortality risk. Plasmatic sodium levels in rabbits decrease in conditions of hyperglycaemia in a similar manner as it occurs in human beings. As hyperglycaemia is quite a common condition in rabbits, simultaneous measurement of plasmatic sodium along with glucose in ill rabbits is advised. Hyponatraemia is a common condition in ill rabbits and, depending on its type (true hyponatraemia or pseudohyponatraemia), of varying clinical relevance. Calculation of plasmatic tonicity is necessary for differentiation of types of hyponatraemia.

Molecular Characterization of a Novel Bovine Viral Diarrhea Virus Isolate SD-15

“…This is evidenced by our previous etiological investigation that both cattle and sheep in the Inner Mongolia region had a very high BVDV infection [ 44 ]. The finding that the majority of BVDV-1 strains from other regions in China were BVDV-1m [ 33 , 45 ], indicating BVDV-1m strains were likely to spread widely in China. Although we had no direct evidence bridging ZM-95 and SD-15 BVDV strain currently, the results that ZM-95 and SD-15 were isolated from pigs and cattle, respectively, in the same region of the Inner Mongolia indicate that BVDV-1m strain is likely the main subgenotype circulating in the Inner Mongolia.…”

The value of clinical pathology in pet rabbit medicine

“…Bonvehi and others (2014) found a prevalence of 39 per cent of hyponatraemia in 356 critically ill rabbits, of which the majority (71.9 per cent) had true hyponatraemia, with 28.1 per cent having pseudohyponatraemia. From looking at the outcome at seven days after initial presentation in 322 of these rabbits, those with severe hyponatraemia (sodium <129 mEq/l) had a mortality rate 2.3 times higher than those with normal sodium levels, suggesting that hyponatraemia can be a useful indicator of mortality risk.…”

“…A paper by Bonvehi and others (2014), summarised on p 554 of this issue of Veterinary Record , provides new information on clinical pathology related to plasma sodium and glucose levels in pet rabbits. Sodium is the most abundant and important extracellular cation, and both volume and tonicity of body fluids are maintained within a narrow normal range by regulation of sodium and water balance.…”

“…The clinical retrospective study by Bonvehi and others (2014) establishes reference intervals for healthy rabbits for plasma sodium using a hand-held blood gas and electrolyte analyser that is now widely available and used in general practice (iStat-1; Abbott Diagnostics, Illinois, USA), and also for calculated osmolarity and tonicity, which have not been previously reported in pet rabbits. The results for sodium levels (136-147 mEq/l) are consistent with previous studies that used different methodologies, and results for calculated osmolarity and tonicity are also similar to those reported for laboratory rabbits using osmometers (real plasma osmolality), confirming that use of the iStat and simple formulae is reliable in pet rabbits, which is very useful for the practitioner.…”

“…Of more interest, and the main focus of the study by Bonvehi and others (2014), is the investigation of the prevalence and types of hyponatraemia in ill pet rabbits, and the relationship between hyponatraemia and hyperglycaemia. Establishing the type of hyponatraemia present using plasma tonicity is vital, as it directs intervention; measurement of sodium levels alone is not sufficient and can lead to misguided treatment that may be detrimental, such as inappropriate use of hypertonic saline or fluid restriction (DiBartola 2012).…”