Clinical Hypocalcemia Research Articles

Single-dose preoperative vitamin D and calcium supplementation to prevent hypocalcemia after total thyroidectomy: a comparative clinical trial

Background Hypocalcemia is not a rare complication after total thyroidectomy. It may be predisposed by preoperative low serum calcium, malignancy, prolonged surgery, inexperienced surgeons, inappropriate use of diathermy, and lack of loop magnifier during surgery. It causes patient distress and may prolong hospital admission time. Calcium and vitamin D administration may help decrease its rate. Patients and methods Two groups of patients undergoing total thyroidectomy were included. Each group included 43 patients. One group was given a single dose of calcium 3 g and vitamin D 40 000 IU on the preoperative day (supplementation group), and no calcium or vitamin D was given to the other group (non-supplementation group). Patients were monitored for clinical hypocalcemia and serum calcium level at 6, 12, 24, and 48 postoperative hours, as well as postoperative vitamin D level and serum calcium after 1 month. Results In the supplementation group, the authors reported three cases of clinical hypocalcemia and seven cases of laboratory hypocalcemia. In the nonsupplementation group, the authors reported 19 patients with laboratory hypocalcemia and 10 patients with clinical hypocalcemia, with significant difference between groups. Postoperative calcium and vitamin D levels were significantly higher in the supplementation group. Conclusion A single-dose preoperative calcium and vitamin D administration is effective in prevention of postoperative hypocalcemia after total thyroidectomy, especially in simple cases. Complicated and malignant cases may need postoperative calcium administration.

Mini-invasive thyroidectomy and intraoperative neuromonitoring: a high-volume single-center experience in 215 consecutive cases.

Endocrine surgery recent evolution has been characterized by introduction of mini-invasive video-assisted technique. When a new technique is introduced in surgical use the rate of adverse events must be the same of previous standardized technique. In MIVAT procedure complication rate and in particular nerve injury risk is associated surgeon's experience. The new approach is the intraoperative neuro-monitoring (IONM) use in MIVAT in order to reduce the laryngeal nerve injury rate in a more technically difficult surgical procedure. We analyzed clinical and surgical data regarding 215 patients treated with MIVAT technique and simultaneous IONM utilization from September 2014 to December 2019 in a single high-volume surgical center. We recorded data regarding age, gender, preoperative diagnosis, surgical time, early postoperative hypocalcemia, hematoma and vocal cord palsy. We compared these data to our first 211 cases of MIVAT (July 2005 to June 2009) at the beginning of the learning curve, performed without using IONM. We tried to highlight the impact of MIVAT and IONM simultaneous use on surgical outcome comparing results to our previous studies, also highlighting the learning curve effect. We detected a postoperative transitory clinical hypocalcemia in 14 patients (6.5%). No postoperative hematoma was recorded. Using I-IONM during thyroidectomy, we recorded in five cases a loss of signal; in three cases (1.4%) we experienced a temporary postoperative vocal cord palsy, only one case of definitive palsy. We did not observe any significant differences in surgical complications rate between the first 211 cases and these last 215 cases. We have not found any statistically significative difference regarding IONM use during MIVAT procedure related to MIVAT performed without IONM. In our previous experience cases series of MIVAT the percentage of transitory nerve palsy reported was 2.4% (non-significant P value). Surgical indication has changed. In our experience we report that the use of IONM in MIVAT is as helpful to improve the safe of procedure. The risk of nerve palsy in literature associated to MIVAT is the same of the related one to classic technique (CT). We have not found statistical positivity to use IONM in MIVAT related to MIVAT without IONM. In our previous experience cases series of MIVAT the percentage of transitory nerve palsy reported was 2.4% (non-significant P value). The most important IONM effect, in our opinion is the "safety feeling" experienced by the surgeon using IONM in a more challenging procedure. As a University Hospital, training surgery residents, we also identified the IONM as a very useful teaching support.

Negative dietary cation-anion difference and amount of calcium in prepartum diets: Effects on milk production, blood calcium, and health

Acidogenic prepartum diets with negative dietary cation-anion difference (DCAD) induce compensated metabolic acidosis, which stimulates calcium (Ca) mobilization before calving and decreases clinical and subclinical hypocalcemia postpartum. This strategy is often combined with limiting dietary Ca concentrations, which historically has been used to mobilize Ca prepartum to prepare cows for lactation. Supplemental dietary Ca in combination with a negative DCAD formulation that does not reverse the effect of compensated metabolic acidosis may be beneficial. Our objective was to determine the effects of prepartum dietary strategies on dry matter intake (DMI), milk production, peripartal Ca status, and health during the transition period in multiparous Holstein cows (n = 81). Treatments during the last 28 d before calving were: (1) positive DCAD diet, +6 mEq/100 g of DM, target urine pH >7.5, low dietary Ca (0.40% DM; CON); (2) negative DCAD diet, -24 mEq/100 g of DM, target urine pH 5.5 to 6.0, low dietary Ca (0.40% DM; ND); or (3) negative DCAD diet, -24 mEq/100 g of DM, target urine pH 5.5 to 6.0, , high dietary Ca (2.0% DM; NDCA). Preplanned treatment contrasts were: (1) CON versus (ND and NDCA), and (2) ND versus NDCA. Individual DMI were recorded daily. Cows were milked 3 times daily, with individual DMI and milk yield summarized by week. Whole blood sampled at calving and 24 h, 48 h, and 4 d after calving was analyzed for ionized Ca concentration, and serum was analyzed for total Ca. Prepartum urine pH for cows fed ND or NDCA averaged 5.7, whereas cows fed CON remained >7.5. During the 3 wk before calving, cows fed CON had greater DMI than cows fed ND or NDCA, with NDCA greater than ND. Postpartum DMI (% of body weight) tended to be less for cows fed CON than for those fed ND or NDCA prepartum. Thresholds for subclinical hypocalcemia were ionized Ca <1.0 mM at 24 h, and total Ca ≤2.125 mM at 48 h after calving. On average, blood Ca for cows fed CON indicated subclinical hypocalcemia, whereas blood Ca for cows fed ND or NDCA was greater than subclinical hypocalcemia thresholds for both ionized Ca and total Ca. No milk production differences were detected. Cows fed CON had an elevated adverse health score (calculated by assigning numerical values to recorded health events) and tended to have an elevated somatic cell count during the fresh period compared with cows fed ND or NDCA. Overall, an acidogenic diet prepartum without or with high Ca improved postpartum Ca status and health. Supplementation of additional Ca to the acidogenic diet had little effect.

Effect of subclinical and clinical hypocalcemia and dietary cation-anion difference on rumination activity in periparturient dairy cows

Rumination involves a complex series of muscle contractions that bring a bolus of ingesta to the mouth for further mastication before it is swallowed again. Healthy cows ruminate 8 to 9 h/d. Hypocalcemia is known to disrupt nerve and muscle function. Our hypothesis was that hypocalcemia in periparturient cows would reduce rumination activity. Twenty-six Holstein cows entering their third lactation or greater were fed a control diet [dietary cation-anion difference (DCAD) = +196 mEq/kg of dry matter (DM)] or a low DCAD diet supplemented with anions (DCAD = -9 mEq/kg of DM) prepartum. Periparturient plasma Ca concentration and rumination rate were determined. Four of 12 control cows developed clinical milk fever, necessitating intravenous Ca therapy. Rumination rate decreased in all cows around the time of calving. Rumination rate on the first and second day of lactation was highly correlated with the cow's plasma Ca concentration on the first day of lactation. In one of our statistical models, a normocalcemic cow was defined as a cow whose plasma Ca concentration remained above 2.00 mM. Cows were retrospectively classified as normocalcemic, subclinically hypocalcemic, or clinically hypocalcemic (milk fever). Only 4 cows were considered normocalcemic, and all had been fed the low DCAD diet. Normocalcemic cows spent more time ruminating on the first day after calving than subclinically hypocalcemic cows or cows with milk fever. Cows with milk fever had a lower rumination rate than normocalcemic cows through d 3 of lactation. Rumination activity in cows with milk fever was almost nondetectable in the hours before and after intravenous Ca treatment for an extended period, despite the return of muscle function that allowed the cows to stand and eructate following treatment. Other statistical models using different definitions of normocalcemia gave qualitatively similar results. Diet had a great effect on plasma Ca concentration and rumination rate. Even when cows with clinical milk fever were removed from the control cow data set, cows on the low DCAD diet had significantly greater plasma Ca concentrations in the first 36 h after calving and a higher rumination rate on d 1 of lactation (248 ± 26 min) than control cows (158 ± 32 min).

Completion Thyroidectomy for Initially Misdiagnosed Differentiated Thyroid Carcinoma-Study of 51 cases

Introduction: Completion thyroidectomy is the removal of any residual thyroid tissue that remains after a less than total thyroidectomy. This procedure is usually done when the final histopathlogy of the excised ipsilateral thyroid lobe reveals papillary or follicular carcinoma.&#x0D; Objective: A retrospective analysis was done of patients undergoing completion thyroidectomy for thyroid malignancy who had undergone surgery elsewhere for solitary thyroid nodule. The incidence of complications in these patients after re-operation was investigated in this study.&#x0D; Material and Method: Our study included a total 51 patients who had undergone thyroid lobectomy for a solitary nodule as initial surgery in our hospital &amp; elsewhere and were admitted in our hospital for completion thyroidectomy when histopathology revealed malignancy in last 5 years (2014-2018).&#x0D; Result: In this study-51 patients were enrolled; among them 42 were female and 9 male. Their mean age was 33.6 years (range-17-59 years). After initial surgery, the histopathology revealed papillary carcinoma in 45 patients (88.24%), follicular carcinoma in 6 patients (11.76%). Four out of 51 patients had recurrent laryngeal nerve palsy after initial surgery (7.8%). None of the patients had clinical hypocalcaemia after 1st surgery. Parathyroid glands are identified and preserved in all patients during completion thyroidectomy. No patient had additional recurrent laryngeal nerve injury in 2nd surgery. Mean follow-up was one year. Transient hypoparathyroidism occurred in 9.8% patients, but no permanent hypoparathyroidism. Seven patients were lost to follow-up.&#x0D; Conclusion: Completion thyroidectomy is a safe and appropriate procedure for the management of initially misdiagnosed differentiated thyroid carcinoma.&#x0D; TAJ 2019; 32(2): 22-26

Do calcium and magnesium deficiencies in reproducing ewes contribute to high lamb mortality?

High lamb mortality continues to be a significant economic and welfare problem within the Australian sheep industry, with 20–30% of lambs born in commercial flocks dying mostly within 3 days of birth. Clinical hypocalcaemia and hypomagnesaemia cause ewe mortality, and, subsequently, either fetal or lamb death, but it is not known whether subclinical deficiencies of calcium (Ca) and magnesium (Mg) compromise lamb survival. This review considers the potential mechanisms through which Ca and Mg deficiencies may influence lamb survival, and factors influencing the risk of deficiency. Pastures grazed by lambing ewes may be marginal in calcium (Ca; &amp;lt;4 g/kg DM) and magnesium (Mg; &amp;lt;0.9 g/kg DM) but also have a high dietary cation–anion difference (&amp;gt;12 meq/100 g DM) and high concentrations of potassium (K; &amp;gt;30 g/kg DM) and nitrogen. In young cereal crops, sodium concentrations are also often low (&amp;lt;0.9 g/kg DM). This combination of minerals and other nutrients creates an imbalance in supply and increases susceptibility to acute Ca (hypocalcaemia) and Mg (hypomagnesaemia) deficiency. Calcium is required for smooth muscle function and has a direct role in uterine contraction, so may influence the duration of parturition. Low Ca and Mg intake both influence insulin release and sensitivity, low Mg results in poor glycaemic control and insulin resistance by impairing both insulin secretion and its action on peripheral tissues, also potentially altering the duration of parturition as well as risk of metabolic disease. Magnesium is also a neuroprotectant that slows the neuronal damage during hypoxia and has been linked with thermogenesis in offspring and increased immunoglobulins in colostrum. These functions indicate potential importance in improving the ease of parturition and improved ability of the newborn lamb to thermoregulate and survive after birth. Subclinical Ca and Mg deficiencies commonly occur in 20% of lambing ewes grazing temperate pastures, so further studies are warranted to investigate whether correction of these deficiencies can improve lamb survival.

Randomized clinical trial assessing the effect of 3 different commercial oral calcium supplementation bolus on calcium dynamics and urine pH after calving

Calcium (Ca) homeostasis is one of the many metabolic challenges faced by a dairy cow during her transition from the dry period into lactation. The use of anionic salts during the dry period is an effective strategy to prevent clinical hypocalcemia, yet subclinical hypocalcemia (SCH) has been reported to affect up to 70% of multiparous cows. Although the use of oral calcium supplements immediately after calving is a commonly adopted method to prevent and treat SCH in multiparous cows, there is a shortage of information comparing different oral calcium products. Thus, the overall goal of this project is to evaluate the effect of different commercially available oral calcium products on postpartum serum calcium profiles of dairy cows. Additional objectives are: determine milk production, urine pH, and Ca concentrations during the first 5 days after oral calcium supplementation. This study is ongoing, with serum and urine samples currently being analyzed to determine Ca concentrations.

Assessment of the level of parathyroid hormone reduction in early postoperative period as a prognostic factor for clinical hypocalcaemia

Assessment of the level of parathyroid hormone reduction in early postoperative period as a prognostic factor for clinical hypocalcaemia

Preventive Effect of Dexamethasone Therapy on the Transient Hypoparathyroidism through Total Thyroidectomy.

This study aimed to investigate whether pre-operative dexamethasone could ameliorate transient hypoparathyroidism outcome through total thyroidectomy. This randomized clinical trial study was conducted on 128 patients underwent total thyroidectomy from March 2014 to April 2015. Patients were randomly assigned to two groups of experimental receiving 8 mg IV of intravenous dexamethasone (n=45) 45 min before skin incision treatment and control (n=83). After the surgery, all patients were evaluated for clinical and laboratory hypocalcaemia. Post-operative transient biochemical hypoparathyroidism and hypocalcaemia did not occur more often in the control group, compared to the dexamethasone group while controlling for the baseline variables. However, there was a significant difference in phosphorus level between the dexamethasone and control groups (P=0.028). A total of 50 (39.1%) patients developed hypocalcaemia after surgery. Moreover, post-operative symptomatic hypocalcemia occurred more frequently in the control group (68%) compared to the dexamethasone group (32%); however, this difference was not statistically significant (P=0.54). The pre-operative administration of dexamethasone reduced post-operative hypocalcemia rate. It is essential to conduct future studies with validated means for better results.

The incidence of post-thyroidectomy hypocalcaemia: a retrospective single-centre audit.

The aim of this single centre retrospective observational record-based audit was to assess the incidence of post-thyroidectomy hypocalcaemia. The setting was a district general hospital in Hertfordshire covering a population of 500,000 people. A total of 196 patients who had had total or completion thyroidectomy during a five-year period were included in the study. The primary outcome measure was to determine the rate of biochemical and symptomatic hypocalcaemia in patients undergoing total or completion thyroidectomy. Secondary outcome measures assessed time taken for biochemical and clinical hypocalcaemia to resolve, whether malignancy affected the rate of hypocalcaemia and if removal of parathyroid glands during surgery were a predictor of hypocalcaemia. The overall incidence of post-thyroidectomy hypocalcaemia (PTHC) within 24 hours was 21.4%. The incidence increased from 6 hours (13.8%) to 24 hours post-thyroidectomy (15.8%) and there was evidence of both transient and delayed PTHC within the first 24 hours. By 6 months post-surgery, 3.6% remained hypocalcaemic and required continual oral supplementation. Patients with benign thyroid disease had a higher risk of PTHC (P = 0.04) and patients younger than 50 years of age had a higher risk of symptomatic hypocalcaemia (P = 0.016). Other clinical factors including sex, type of surgery, neck dissection, oral calcium and/or vitamin D supplementation and inadvertent histological parathyroid gland excision were not associated with an increased incidence of PTHC or symptomatic hypocalcaemia. Our audit shows that the rate of PTHC within our population was below the national average with higher risk in benign thyroid disease.

Effects of the c.8514C > T polymorphism in the osteopontin gene (OPN) on milk production, milk composition and disease susceptibility in Holstein-Friesian cattle

Studies into the polymorphism of the bovine osteopontin (OPN) gene have so far been focussed on the association between milk production and milk composition, lactation persistency and the rate of growth and weight gain in young cattle. Results obtained by some authors have shown different associations for various milk parameters. Even though osteopontin is an essential component of immunological response, the relationship between the polymorphism of the osteopontin gene and the incidence of diseases in cows has not been researched as yet. The purpose of this study was to analyse the c.8514 C > T polymorphism and its association with milk parameters such as: average daily yield, average protein and fat percentage and average somatic cell count in Holstein-Friesian cattle. The study also included an analysis of the impact of polymorphism on the incidence of the most frequent cattle diseases such as: clinical mastitis (CM), ovarian cysts (OC), clinical hypocalcaemia (CH) and pyometra (P). The study population of cows was found to have two alleles in the analysed locus of the osteopontin gene: C (0.529) and T (0.471), and three genotypes: CC, CT and TT (0.288, 0.482 and 0.230, respectively). Although the study showed no significant association between the polymorphism of the OPN gene and the incidence of diseases or milk parameters, it is an important contribution to research aimed at identifying the most essential SNPs which could be used for marker-assisted selection in dairy cattle herds.HighlightsThe study population was found to have two alleles in the locus of the osteopontin gene (c.8514C>T ): C and T, and three genotypes: CC, CT and TT.CT was the most frequent genotype of the osteopontin gene (c.8514C>T ), identified in about 48% of the study population of cows.No significant differences were focused between the genotypes in the c.8514C>T locus and the milk parameters and the incidence of cattle diseases.

Effects of prepartum dietary cation-anion difference intake on production and health of dairy cows: A meta-analysis

Prepartum diets influence cow performance for weeks to months postpartum. This observation leads to questions about milk yield and physiological and health responses to diets with negative dietary cation-anion difference (DCAD). Further, responses to increased intake of a diet with lower DCAD (Eq/d) have not been explored using meta-analysis. Our objectives were to explore the effects of prepartum DCAD intake on metabolism and production and health as well as the potential for differences in intake of other macrominerals to influence responses to differences in DCAD intake using classical meta-analytical methods. Not all treated groups were fed a diet with negative DCAD, and the effect studied is that of reducing the DCAD. We hypothesized that reducing DCAD intake would improve Ca metabolism and postpartum performance. We used a maximum of 58 comparisons from 31 experiments and a total of 1,571 cows. Intakes of DCAD were 2.28 Eq/d and -0.64 Eq/d for the control, higher DCAD and treated, lower DCAD groups, respectively. Diets with lower DCAD reduced urine pH [standardized mean difference (SMD) = 1.90 and weighted mean difference (WMD) -1.23 pH]. Intake of lower DCAD decreased prepartum DMI (SMD = 0.23; WMD = 0.29 kg/d), increased postpartum DMI (SMD = 0.40; WMD = 0.63 kg/d), and increased milk yield (SMD = 0.172). However, we found an interaction with parity; diets with lower DCAD increased milk yield in parous cows (SMD = 0.29; WMD = 1.1 kg/d) but resulted in numerically lower milk yield in nulliparous cows (SMD = -0.20; WMD = 1.28 kg/d) compared with controls. The FCM yield increased with treatment (SMD = 0.12; WMD = 0.56 kg/d); however, yield of treated cows tended to be greater in parous cows but smaller for nulliparous cows compared with controls. Milk fat percentage, milk fat yield, and milk protein percentages were not affected by treatment, although milk protein yield tended to increase in cows fed the lower DCAD diet (SMD = 0.21; WMD = 0.02 kg/d). Treatment increased blood Ca (SMD = 0.53; WMD = 0.13 mM) and P (SMD = 0.40; WMD = 0.13 mM) on the day of calving and Ca postpartum (SMD = 0.36; WMD = 0.06 mM). Treated cows had smaller concentration of blood BHB before calving than controls (SMD = -0.39; WMD = -0.04 mM). Reducing DCAD in cows resulted in decreased risks of clinical hypocalcemia (risk ratio = 0.60) and retained placenta (risk ratio = 0.59), and reduced the odds of metritis (odds ratio = 0.46) and overall disease (OR = 0.61). We observed no effect on risk of abomasal displacement or mastitis and no effect of differences between treated and control cows in Ca intake (g/d) on the outcomes evaluated. A positive role for increased Mg intake between groups for increased milk fat yield and in reducing the risk of retained placenta was identified. Diets with lower DCAD improved performance of parous dairy cows, and our findings suggest a need for more studies on the effects of a lower DCAD on nulliparous transition cows.

Effect of diets containing sulfate or chloride-based anionic salts, fed to grazing prepartum dairy cows, on concentrations of Ca in plasma, disease incidence and milk yield

AIMS: To compare the effect of two partial mixed ration diets containing either sulfate or chloride-based anionic salts, fed to grazing prepartum dairy cows, on concentrations of Ca, Mg, P and beta-hydroxybutyrate (BHB) in plasma, disease incidence and milk yield during the early postpartum period.METHODS: The study was conducted on a seasonal-calving grazing dairy farm located in Benton (MO, USA). In August 2016, two groups of 200 cows were randomly assigned at 30 days before expected parturition to receive either a sulfate or chloride-based anionic diet, to achieve a dietary cation–anion difference (DCAD) of −25 mEq/kg DM. Cows were fed partial mixed rations to provide 50% of their DM intake, with 50% provided by grazing fescue pasture. Urine samples were collected from 20 cows from each group once a week for 5 weeks until calving for pH assessment. At parturition, 42 cows per group were selected at random and blood samples collected on Days 1, 2, 3 and 7 postpartum. The study continued until 100 cows per group calved. Health events and cumulative milk yield until 30 days postpartum were recorded. Concentrations of Ca, P, and Mg in plasma at Days 1, 2, 3, and 7, and BHB in plasma at Day 7 postpartum were assessed.RESULTS: Mean urine pH was lower in cows in the chloride than sulfate group (p≤0.06) on four of five sampling occasions. Mean concentrations of Ca in plasma on Day 1 were 2.00 (95% CI=1.94–2.05) and 1.91 (95% CI=1.88–1.97) mmol/L for the chloride and sulfate groups, respectively (p=0.15), and on Day 3 were 2.03 (95% CI=1.97–2.08) and 1.90 (95% CI=1.84–1.96) mmol/L, respectively (p=0.038). Concentrations of Mg, P and BHB in plasma and incidence of diseases postpartum were similar in both groups (p>0.05). There were no cases of clinical hypocalcaemia in either group.CONCLUSIONS AND CLINICAL RELEVANCE: Prepartum cows fed a partial mixed ration with a negative DCAD containing chloride-based anionic salts and free access to a fescue pasture had lower prepartum urine pH, and higher concentrations of total Ca in plasma during the first week postpartum, than cows receiving a partial mixed ration containing sulfate-based anionic salts.

Outcomes of Per-oral Endoscopic Thyroidectomy (POET) – A New Trend for Scarfree Thyroidectomy

Objectives: This paper discusses the surgical outcomes of POET compared to open thyroidectomy (OT) and other approaches of video thyroidectomy (VT) such as chest or axillary approach to investigate the feasibility of POET as a safe alternative. Background: Per-Oral Endoscopic Thyroidectomy (POET) is a developing novel technique based on the principles of minimally invasive surgery offering “scar-free” thyroidectomy. To date, results from various individual centers have been published internationally but none from UK, Malaysia or Singapore. Methods: This is a single tertiary hospital, single surgeon based retrospective analysis of 98 selected patients (mean age: 43.5 years old) undergoing POET in 12 months (July 2017 to July 2018). It records the complication rates post-operatively until day of discharge. Results: The average length of stay is 2 days and average time of operation is 69 minutes. There was no blood loss &gt;100ml and no wound infection recorded among the 98 patients. Only 1 out of 98 patients (1%) had permanent recurrent laryngeal nerve (RLN) palsy. Clinical hypocalcemia described as cramp and lip paresthesia was experienced by 6 patients (6%). 5% had transient mental nerve injury described as mental paresthesia. Conclusion: POET is a promising safe alternative technique to thyroidectomy with comparable surgical outcome yet significantly better cosmetic outcome. This technique has a strong potential to be useful when lowering the rate of developing keloidal scar and hypertrophic scaring. POET can be an option to offer patients who are especially driven to achieve perfect cosmesis.

Presumptive Glucocorticoid-Induced Refractory Hypocalcemia in a Dog with Idiopathic Immune-Mediated Hypoparathyroidism, Thrombocytopenia, and Hemolytic Anemia

Clinically relevant hypocalcemia is a well-documented complication of glucocorticoid administration in people with hypoparathyroidism. The current report describes the phenomenon in a dog. A 7 yr old neutered male Pomeranian was diagnosed with immune-mediated thrombocytopenia, immune-mediated hemolytic anemia, and primary hypoparathyroidism. This dog required long-term parenteral calcium gluconate to prevent clinical hypocalcemia despite appropriate doses of oral calcitriol and calcium carbonate. This is the first description of clinically significant presumptive glucocorticoid induced hypocalcemia in a dog with primary hypoparathyroidism.

Risk factors and outcomes of incidental parathyroidectomy in thyroidectomy: A systematic review and meta-analysis.

IntroductionPostoperative hypocalcemia is the most common complication of thyroidectomy. Incidental parathyroidectomy (IP) was thought to be associated with postoperative hypocalcemia. However, according to previous studies, the risk factors and clinical outcomes of IP remain controversial.MethodsEligible studies were searched in databases including PubMed, Web of Science, and EMBASE from January 1990 to September 2017. Articles focusing on the relationship between IP and postoperative hypocalcemia were included. The risk of publication bias was assessed using Begg’s test and Egger’s regression asymmetry test. Pooled analysis was performed to evaluate the effect of IP on postoperative hypocalcemia and related risk factors. Sensitivity analysis was also conducted to test the stability of our results. The effects of hypocalcemia type, permanent definition, IP incidence, total thyroidectomy, and malignancy operation were also examined using a further subgroup analysis.ResultsThirty-five studies were finally included in the analysis after an exhaustive literature review. Pathology data demonstrate that incidental parathyroidectomy occurred in various locations: intrathyroidal (2.2–50.0%), intracapsular (16.7–40.0%) and extracapsular (15.7–81.1%) regions. Overall, the analysis found that malignancy (RR = 1.60, 95% CI: 1.27 to 2.02; p< 0.0001), central neck dissection (RR = 2.35, 95% CI: 1.47 to 3.75; p = 0.0004), total thyroidectomy (RR = 1.42, 95% CI: 1.20 to 1.67; p< 0.0001) and reoperation (RR = 1.81, 95% CI: 1.20 to 2.75; p = 0.005) were significant risk factors of IP in thyroid surgery. There was an obvious effect of IP on temporary/permanent (RR = 1.59, 95% CI: 1.37 to 1.84; p< 0.0001) and permanent (RD = 0.0220, 95% CI: 0.0069 to 0.0370; p = 0.0042) postoperative hypocalcemia. Sensitivity analysis showed that these results were robust. The subgroup analysis found that IP played a significant role in both biochemical and clinical hypocalcemia in thyroidectomy (p < 0.0001 and p = 0.0003, separately). The association of IP and permanent hypocalcemia using different definitions (6 months or more than 12 months) was also confirmed by the analysis. IP increased the incidence of temporary/permanent and permanent hypocalcemia for cases undergoing total thyroidectomy (40.4% vs 24.8% and 5.8% vs 1.4%, respectively). Thyroidectomy with IP was associated with more permanent hypocalcemia (RR = 3.10, 95% CI: 2.01 to 4.78; p< 0.0001) in malignant cases but was not associated with temporary/permanent hypocalcemia.ConclusionsMalignancy, central neck dissection, total thyroidectomy and reoperation were found to be significant risk factors of IP. IP increases the risk of postoperative hypocalcemia after thyroidectomy. We recommend a more meticulous intraoperative identification of parathyroid gland in thyroidectomy to reduce IP, particularly for total thyroidectomy and malignancy cases.

Risk factors for subclinical hypocalcaemia, and associations between subclinical hypocalcaemia and reproductive performance, in pasture-based dairy herds in New Zealand

AIMSTo estimate the herd-level prevalence of subclinical hypocalcaemia within 3 days of calving, to determine cow and herd-level risk factors for this condition, and associations with reproductive performance, in pasture-based cows in New Zealand.METHODSBetween 10 and 15 clinically healthy cows ≥3-years-old (n=1,051) were enrolled from 76 spring-calving dairy herds. Blood samples were collected from all cows on 1 or 2 days within 3 days of calving, and assayed for total concentrations of Ca in serum. Subclinical hypocalcaemia was defined as concentrations of Ca in serum ≤2.14 mmol/L, and herd-level prevalence was the percentage of sampled cows with subclinical hypocalcaemia. Breeding and pregnancy diagnosis data were obtained for each cow to calculate reproductive outcomes. Herd-level data about management practices were collected from farmers at enrolment. Associations between cow-level variables, and reproductive outcomes, and subclinical hypocalcaemia were examined using multivariable logistic regression mixed models. Associations between herd-level variables and prevalence of subclinical hypocalcaemia were examined using a multivariable linear regression model.RESULTSMean herd-level prevalence of subclinical hypocalcaemia was 52 (95% CI=49–55)%. Risk of subclinical hypocalcaemia at the cow-level was associated with an interaction between age of cow and interval from calving to sampling (p=0.03). Increasing age of cow was associated with increased risk of subclinical hypocalcaemia, and cows sampled on the day of calving had an increased risk compared with cows sampled 1 or 2 days after calving. Increased herd-level prevalence of subclinical hypocalcaemia was associated with feeding grass silage (p=0.06) or maize silage (p=0.004), and feeding increasing amounts of elemental Mg in the form of magnesium oxide (p=0.02). The mean farmer-reported herd-level prevalence of clinical hypocalcaemia was 2.9 (95% CI=2.1–3.8)%. Subclinical hypocalcaemia was not associated with any of the reproductive outcomes measured.CONCLUSIONS AND CLINICAL RELEVANCEThere was a high prevalence of subclinical hypocalcaemia in the pasture-fed, spring-calving dairy herds sampled and a large between-herd variation in prevalence. Subclinical hypocalcaemia increased with increasing age, and declined with time postpartum. Herd-level prevalence was associated with feeding grass silage and maize silage to pre-calving cows and with increasing amounts of supplemented magnesium oxide. Subclinical hypocalcaemia was not associated with reproductive outcomes.

Short communication: Effect of dietary phosphorus deprivation in late gestation and early lactation on the calcium homeostasis of periparturient dairy cows

Environmental concerns with P of animal origin polluting surface waters are leading to legal incentives aimed at reducing the dietary P content of dairy cow rations to the lowest possible level that does not negatively affect health and productivity. The objective of the present study was to determine the effect of feeding rations with low dietary P content in late gestation on the Ca homeostasis of the periparturient dairy cow. Eighteen multiparous dairy cows were either fed a P-deficient (0.15% P in dry matter antepartum and 0.20% P in dry matter postpartum) but otherwise balanced ration or a control ration with adequate P content (0.28% P in dry matter antepartum and 0.44% P in dry matter postpartum) during the last 4 wk of gestation until d 10 postpartum. Blood was obtained before initiation of P-deprivation (baseline) and -10, -2, +1, +3, and +10 d relative to parturition to be analyzed for plasma concentrations of Ca [Ca] and inorganic phosphate [Pi]. In addition, plasma concentrations of parathyroid hormone [PTH], the bone resorption marker CrossLaps [CTX], 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D were determined in a subset of samples. Feeding a P-deficient diet for 4 wk antepartum positively affected the Ca homeostasis of periparturient cows. Clinical hypocalcemia occurred in 3/9 control and 0/9 P-deprived cows. [Calcium], [PTH], and plasma concentrations of vitamin D metabolites did not differ between groups until parturition, whereas [Pi] was decreased and [CTX] significantly increased in P-deprived animals. At parturition [PTH] was significantly greater in control cows compared with P-depleted cows. The P-deprived cows had significantly higher [Ca] than control cows on d +1 (2.46 ± 0.11 vs. 2.27 ± 0.41 mmol/L) and +2 (2.61 ± 0.13 vs. 2.35 ± 0.25 mmol/L). Plasma [CTX] was significantly higher in P-deprived than in control cows on d +2. Bone resorption and the typical increase in 1,25-dihydroxyvitamin D in periparturient P-deprived cows seemed to occur despite the smaller rise of [PTH], suggesting either greatly increased sensitivity to PTH or bone mobilization independent of PTH. Future studies must explore potentially negative effects of P-deprivation antepartum on health and productivity of the dairy cow in the following lactation.

Association of postpartum hypocalcemia with early-lactation milk yield, reproductive performance, and culling in dairy cows

Periparturient hypocalcemia is frequently observed and considered as a gateway disease that is associated with various health issues. The objective of this study was to evaluate the association of hypocalcemia with early-lactation milk yield, reproductive performance, and culling across a large number of different managerial systems. A prospective cohort study was conducted based on a convenience sample of 125 dairy herds from 8 federal states of Germany between February 2015 and August 2016. A blood sample was drawn from 1,709 animals within 48 h after parturition and analyzed for serum calcium concentration. After discarding cows (n = 283) with missing data, a total of 1,426 cows were considered for final analyses. The median time from calving to sampling was 14.0 h (interquartile range = 5.0-24.9 h). For each herd, a record of the herd management software was requested 150 d after the last cow was sampled. Serum calcium concentration of each cow was associated with early-lactation milk yield (Dairy Herd Improvement Association equivalent test 1 to 3), reproductive performance [days in milk (DIM) at first artificial insemination (AI), pregnancy at first AI, time to pregnancy within 150 DIM], and culling (until 60 DIM) data. Generalized linear mixed models were used to analyze continuous or categorical data. Shared frailty models were used for time to event data. Five different thresholds were used to define hypocalcemia. Thresholds ranged from 1.8 to 2.2 mmol/L using 0.1-mmol/L increments. Clinical hypocalcemia was defined as serum calcium concentration <2.0 mmol/L in combination with clinical signs (e.g., recumbency). The effect of hypocalcemia on milk yield was conditional on parity. In primiparous cows a serum calcium concentration <2.0 mmol/L (6.4% of cows were below this threshold) had no effect on milk production, whereas there was a tendency for multiparous cows with a serum calcium concentration <2.1 mmol/L (63.2% of cows were below this threshold) to produce 0.80 kg/d more milk compared with multiparous cows at or above the threshold. Multiparous cows suffering from clinical hypocalcemia produced 2.19 kg/d less milk compared with normocalcemic cows in early lactation. Calcium status was not associated with days to first insemination. Cows with a serum calcium concentration <1.9 mmol/L (34.6% of cows below this threshold) had decreased odds (odds ratio = 0.56) of pregnancy at first AI. A serum calcium concentration <1.8 mmol/L (24.1% of cows below this threshold) had a significant effect on time to pregnancy. Compared with animals with a serum calcium concentration ≥1.8 mmol/L, the hazard of becoming pregnant within 150 DIM was reduced when cows had a serum calcium concentration <1.8 mmol/L (hazard ratio = 0.68). Cows with a serum calcium concentration <2.0 mmol/L (44.3% of cows were below this threshold) had a 1.69 times greater hazard of being culled within the first 60 DIM compared with normocalcemic animals. The present study shows that the association of hypocalcemia with milk yield was conditional on parity and serum calcium concentration measured once within 48 h after calving. Considering reproductive performance and culling in early lactation, a negative effect of postpartum hypocalcemia was demonstrated.

Can neutral dietary cation-anion difference (DCAD) decrease occurrence of clinical periparturient hypocalcaemia in dairy cattle?

Adjusting the dietary cation-anion difference (DCAD) is one of the most efficient ways to stimulate calcium homeostasis in periparturient dairy cattle. However, adjusting DCAD to the recommended negative values (-100 to -150 mEq/kg) is associated with decreased food intake and metabolic acidosis. The critical conditions of the animals at peripartum (i.e. drastic hormonal changes, decreased appetite and negative energy balance) can be detrimental to the health, productivity and welfare of the animals if combined with decreased feed intake caused by unpalatable acidogenic salts. In a cross-sectional study, we analysed the ration of eight small to large dairy herds with intensive husbandry systems, including 6949 dry cows. Sodium, potassium, chlorine and sulfur concentrations in the feed were determined and DCAD was calculated. The DCAD of the ration of the farms ranged from -33.5 to +24.7 mEq/kg. Parturient paresis (PP, or milk fever) prevalence was investigated and correlated to DCAD values. Clinical PP occurrence in the dairies of this investigation on average declined by 87% (ranging from a 97% decline to 5% increase). This indicates that adjusting DCAD at neutral values (0 ± 30 mEq/kg range) may both lower the PP prevalence and increase ration palatability by lowering acidogenic salts in the ration. Further research is recommended to investigate the effects of neutral DCAD on subclinical hypocalcaemia and food intake of the cattle.