Thyroid disorders represent the most prevalent endocrine diseases globally, affecting individuals across all ages and genders (1). Thyroidectomy remains a common surgical intervention for various thyroid pathologies, including thyroid malignancy, multinodular goitre, and hyperthyroidism (2). Despite its therapeutic value, thyroidectomy carries the risk of postoperative complications, among which hypocalcemia is one of the most frequent and clinically significant (3). The incidence of post-thyroidectomy hypocalcemia varies substantially, ranging from 3.1% to 100% due to differences in definitions and assessment criteria (4). The British Association of Endocrine and Thyroid Surgeons defines hypocalcemia as corrected calcium <2.10 mmol/L on postoperative day one, with the fourth national audit reporting an incidence of 24.9% and permanent hypocalcemia in 12.1% of patients (4). Internationally, incidence rates range from 1.6% to 50% (5,6), whereas Indian studies report rates between 9.3% and 38.4% (7). Injury or devascularization of the parathyroid glands (PTG) is considered the most common mechanism of post-thyroidectomy hypocalcemia, resulting from inadvertent excision, venous congestion, or compromised arterial supply (8). Additional mechanisms, including hungry bone syndrome and intraoperative hemodilution, have also been described (8). Clinically, hypocalcemia may present with paraesthesia, muscle cramps, tetany, seizures, or cardiac arrhythmias (9). The disruption of calcium homeostasis primarily results from PTG injury during surgery (10). Several risk factors have been identified, such as total thyroidectomy, thyroid cancer, Graves’ disease, recurrent goitre, and reoperative neck surgery, all of which increase the likelihood of parathyroid injury (11,12). Early recognition and timely supplementation with calcium and vitamin D can prevent severe complications and reduce morbidity (10,13). Understanding the local incidence and clinical profile of post-thyroidectomy hypocalcemia is essential for improving perioperative care, enhancing risk stratification, and strengthening patient counselling. This study was undertaken to address this need in a tertiary care setting. Aims and Objectives Primary Objective: To estimate the incidence of hypocalcemia following thyroidectomy. Secondary Objective: To correlate hypocalcemic features with serum calcium levels in post-thyroidectomy patients.

This prospective observational study was conducted at IMS and SUM Hospital on patients who underwent thyroidectomy between June 2022 and May 2024, after obtaining informed consent. A total of 76 patients were enrolled using universal sampling. Patients of all age groups and both sexes undergoing total thyroidectomy or completion thyroidectomy for benign, malignant, toxic or non-toxic thyroid disorders were included. Patients with primary or prior parathyroid pathology, those already on calcium supplementation, pre-existing hypocalcemia, history of parathyroid autotransplantation, or ongoing therapy for osteoporosis were excluded from the study. All patients underwent detailed history taking, general examination, and thorough ear, nose, throat and neck examination. Routine preoperative investigations included complete haemogram, viral markers (HBsAg, HIV, HCV), blood sugar, renal function tests, chest radiograph (PA view), and pre-anesthesia assessment. Serum calcium values were measured preoperatively and on postoperative day 1, day 3, day 7, and at 1, 3 and 6 months postoperatively. Surgical specimens were sent for histopathological examination. Patients were monitored clinically during their hospital stay for signs and symptoms of hypocalcemia such as paresthesia, numbness, muscle cramps, tetany, carpopedal spasm (Trousseau’s sign) and Chvostek’s sign. Normal serum calcium was considered between 8.6 and 10.3 mg/dL. Management of hypocalcemia was based on institutional protocol, wherein patients with serum calcium >8–8.5 mg/dL received elemental calcium 1200 mg/day, those with >7.5–<8 mg/dL received 2400 mg/day, and patients with levels <7.5 mg/dL associated with symptoms received 3000–6000 mg/day. In severe cases, intravenous calcium therapy with one ampoule of 10% calcium gluconate (equivalent to 90–180 mg elemental calcium) diluted in 50 mL of 5% dextrose infused over 10–20 minutes followed by a continuous infusion of 0.5–1.5 mg/kg/h over 8–10 hours was administered. Oral calcium carbonate supplements were administered in divided doses of ≤1 g. Intravenous calcium therapy was continued until symptomatic relief was achieved.

Seventy-six patients who underwent thyroidectomy were included in the present study. The demographic, clinical and biochemical characteristics of the participants are summarized in the following tables. The overall characteristics demonstrate that thyroid disorders necessitating surgical intervention were more frequent among middle-aged individuals and females. Table 1. Demographic characteristics of study participants Variable Category N % Age (years) 15–20 2 2.6 21–30 4 5.3 31–40 28 36.8 41–50 23 30.3 51–60 12 15.8 61–70 7 9.2 Gender Male 7 9.2 Female 69 90.8 The majority of participants were between 31–40 years of age (36.8%), followed by the 41–50 year age group (30.3%). A smaller proportion of participants were below 30 years or above 60 years of age. This trend suggests that thyroid disorders requiring surgery are predominantly seen in middle-aged adults. The sample was predominantly female, comprising 90.8% of the cohort, which is consistent with the recognized higher prevalence of thyroid disorders among females. Although not analyzed for significance, this skewed sex distribution highlights the gender-linked epidemiological pattern commonly observed in endocrine disorders. Table 2. Pre-operative indications among study participants Pre-operative indication N % Multi nodular goitre 58 76.3 Single nodular goitre 4 5.3 Toxic multi nodular goitre 6 7.9 Papillary carcinoma thyroid 5 6.6 Recurrent thyroid nodule 3 3.9 Multi nodular goitre (MNG) was the most frequent indication for surgery, accounting for more than three-quarters of the cases. Toxic MNG constituted 7.9% of cases, reflecting a smaller subset with functional thyroid pathology. Malignant pathology in the form of papillary carcinoma was seen in 6.6% of patients, while recurrent thyroid nodules accounted for 3.9%. These findings reinforce that benign multinodular disease remains the dominant cause for thyroidectomy in routine clinical practice. Table 3. Post-operative histopathological examination (HPE) findings HPE diagnosis N % Nodular goitre 15 19.7 Colloid goitre 13 17.1 Follicular adenoma 12 15.8 Hashimoto thyroiditis 10 13.2 Papillary carcinoma thyroid 10 13.2 Adenomatous goitre 5 6.6 Graves’ disease 4 5.3 Lymphocytic thyroiditis 4 5.3 Hyperplastic goitre 3 3.9 Postoperative histopathology demonstrated a diverse distribution of benign and autoimmune thyroid pathology. Nodular goitre was the most common histopathological diagnosis (19.7%), followed closely by colloid goitre and follicular adenoma. Autoimmune thyroiditis, including Hashimoto and lymphocytic variants, together constituted a considerable proportion, reflecting the autoimmune basis underlying many thyroid disorders in this population. Papillary carcinoma was confirmed in 13.2% of patients, highlighting the coexistence of malignant pathology in a notable minority. The discordance between pre-operative indication and HPE in some cases underscores the role of histopathology in definitive diagnosis. Table 4. Serum calcium levels at different postoperative time points Time period Mean SD Pre-operative 9.96 0.80 Post-operative day 1 9.41 0.79 Post-operative day 3 9.03 1.12 Post-operative day 7 8.90 1.37 1 month postoperative 9.21 0.92 3 months postoperative 9.36 0.80 6 months postoperative 9.45 0.75 Repeated measures ANOVA demonstrated a statistically significant difference in serum calcium levels across time points (F = 25.60, p < 0.001). Serum calcium decreased progressively during the immediate postoperative period, reaching the lowest mean value on day 7, followed by gradual recovery by the first postoperative month and near-normalization by the third and sixth months. This pattern reflects the transient postoperative effect of thyroidectomy on calcium homeostasis, likely attributable to temporary parathyroid dysfunction or devascularization. Table 5. Incidence and clinical manifestations of postoperative hypocalcemia Parameter Category N % Hypocalcemia Present 31 40.8 Absent 45 59.2 Signs/Symptoms on POD-7 Carpopedal spasm 9 11.8 Chvostek sign with perioral numbness 6 7.9 Perioral numbness 6 7.9 No symptoms 55 72.4 Hypocalcemia occurred in 40.8% of participants, indicating that postoperative decline in calcium levels was a common biochemical occurrence. However, a much smaller proportion developed clinically evident symptoms, with 11.8% demonstrating carpopedal spasm and 7.9% exhibiting Chvostek sign accompanied by perioral numbness. The discrepancy between biochemical and clinical hypocalcemia suggests that early biochemical changes may not always translate to symptomatic hypocalcemia, possibly due to compensatory mechanisms or timely supplementation. Table 6. Type of hypocalcemia and treatment modalities Parameter Category N % Type of hypocalcemia Transient 29 93.5 Permanent 2 6.5 Treatment modality Oral supplementation 20 64.5 Intravenous calcium 11 35.5 Among patients with hypocalcemia, transient hypocalcemia was the predominant type (93.5%), while permanent hypocalcemia was observed in 6.5% of cases. Most patients were managed with oral calcium supplementation, whereas intravenous therapy was required in one-third of patients, typically those with symptomatic or lower biochemical calcium levels. These findings emphasize that although postoperative hypocalcemia is frequent, permanent hypocalcemia is uncommon, aligning with patterns reported in endocrine surgical literature. Table 7. Correlation between serum calcium levels and clinical parameters Parameter Correlation (r) range Significance Gender −0.186 to 0.012 Not significant Post-operative HPE −0.308 to −0.242 Significant Risk factors 0.124 to 0.235 Significant for postoperative 1 month Transient vs permanent 0.274 to 0.781 Significant across all time points Symptoms on POD-7 0.240 to 0.751 Significant across all time points Correlation analysis revealed that gender showed no significant association with serum calcium levels at any time point. Histopathological diagnosis demonstrated a significant negative correlation at multiple postoperative intervals, suggesting that specific pathological subtypes may influence biochemical recovery patterns. The distinction between transient and permanent hypocalcemia showed a strong positive correlation with serum calcium trends, underscoring the clinical utility of early postoperative biochemical values in predicting long-term outcome. Symptoms on POD-7 correlated positively with serum calcium levels across time, reinforcing the relevance of clinical signs as surrogate markers of biochemical status. In summary, the results indicate that hypocalcemia is a frequent postoperative finding following thyroidectomy, with a characteristic transient pattern of biochemical decline and gradual recovery. Permanent hypocalcemia was rare, and most cases responded to conservative oral calcium therapy. The biochemical profile, combined with clinical manifestations and histopathological patterns, provides insight into postoperative calcium homeostasis in thyroidectomy patients.

The present study aimed to estimate the incidence of hypocalcemia following thyroidectomy and to correlate hypocalcemic features with postoperative serum calcium levels in a tertiary care setting. The findings demonstrated a substantial incidence of post-thyroidectomy hypocalcemia, underscoring the importance of perioperative biochemical surveillance and early clinical recognition. A majority of patients in the present cohort were middle-aged adults, and the study population was predominantly female. This demographic pattern reflects the known epidemiology of thyroid disorders, which are more commonly observed in women, often influenced by hormonal and autoimmune mechanisms, as supported by Chen et al. (11). Multinodular goitre was the most common indication for thyroidectomy, consistent with surgical trends reported in several recent studies (3,5,8). Histopathological examination demonstrated a broad spectrum of benign, autoimmune, and malignant thyroid pathologies, reinforcing the heterogeneity of thyroid disorders requiring surgical intervention. The overall incidence of postoperative hypocalcemia in this study was 40.8%, which falls within the broad range reported in the literature. Previous studies have identified post-thyroidectomy hypocalcemia rates between 1.2% and 40% (17), while others have reported even higher rates depending on operative extent, definitions used, and surveillance duration (18,22,26). Variability in reported incidence has been attributed to multiple factors including incidental parathyroidectomy (5,24), extent of surgery (22), preoperative vitamin D deficiency (26), and patient-specific risk factors (6,7,24). In the present study, the predominance of total thyroidectomy (93.4%) likely contributed to the higher incidence, as total thyroidectomy remains the strongest surgical predictor of postoperative hypocalcemia, as demonstrated by Del Rio et al. (22) and confirmed in systematic reviews (20,21,23). Serum calcium levels showed a significant transient postoperative decline with subsequent recovery, indicating temporary parathyroid insufficiency. This pattern is consistent with the pathophysiology described by Lorente-Poch et al. (12), who defined transient hypoparathyroidism as a reversible functional impairment related to intraoperative manipulation, ischemia, or devascularization of the parathyroid glands. The present study found transient hypocalcemia in 93.5% of cases, whereas permanent hypocalcemia was uncommon, occurring in 4.4% of patients. Similar findings have been reported in the BAETS registry, where 23.6% of patients required supplementation and 7.3% had persistent requirements six months after surgery (25). Clinical symptoms such as carpopedal spasm and perioral numbness were observed in a subset of patients and correlated with biochemical hypocalcemia. The association of these manifestations with hypocalcemia is well recognized, as tetany, Chvostek sign, and Trousseau sign represent classic clinical indicators (19–21). However, the presence of biochemical hypocalcemia in asymptomatic individuals highlights the importance of routine postoperative biochemical monitoring to prevent delayed complications, including prolonged hospitalization (17) and cardiac or neurological sequelae (22–24,25). Risk factor assessment in the present study identified huge goitre and short neck/obesity as notable contributors. Similar mechanical and anatomical risk factors have been reported to complicate surgical dissection and increase parathyroid vulnerability (22,24). Correlation analysis in the current study demonstrated significant associations between postoperative histopathology, clinical symptoms, and calcium trends, suggesting that perioperative variables may assist in predicting biochemical outcomes. Previous studies have emphasized the utility of early markers such as parathyroid hormone (PTH) in predicting hypocalcemia (23,25,26), and the incorporation of biochemical predictors into postoperative algorithms continues to evolve (20–22). Management strategies in the present cohort involved predominantly oral calcium supplementation, with intravenous supplementation reserved for more symptomatic or severe declines. Postoperative supplementation with calcium and vitamin D is supported by several randomized and observational studies as a means of reducing symptomatic hypocalcemia and hospital stay (20,22,25). The transient nature of hypocalcemia in most patients further supports the effectiveness of early and proactive supplementation strategies aimed at minimizing morbidity. Taken together, the findings of this study reaffirm that postoperative hypocalcemia remains a frequent, clinically significant, yet largely transient complication of thyroidectomy. Early risk stratification using clinical, biochemical, and histopathological parameters is essential to optimize outcomes. A multidisciplinary perioperative approach involving surgical, anesthetic, and endocrine teams remains fundamental in minimizing the risk of complications and improving long-term patient outcomes. Future studies incorporating larger cohorts and longer follow-up durations are warranted to further refine predictive models and standardize evidence-based postoperative supplementation protocols.

The present study demonstrated that hypocalcemia is a common postoperative complication following thyroidectomy, occurring in 40.8% of patients in this cohort. Serum calcium levels exhibited a significant transient decline in the immediate postoperative period, with a subsequent recovery pattern in most patients, consistent with transient parathyroid dysfunction. Clinical manifestations such as carpopedal spasm and perioral numbness were observed in a subset of individuals and correlated with biochemical findings. Permanent hypocalcemia was infrequent, indicating favorable long-term outcomes with appropriate clinical management. The findings reinforce the importance of vigilant perioperative monitoring, timely recognition of risk factors, and early supplementation strategies to prevent symptomatic hypocalcemia and reduce morbidity. Predictive indicators such as operative extent, histopathological features, and clinical symptoms may aid clinicians in postoperative decision-making. Although hypocalcemia remains a frequent complication, its largely transient nature highlights the effectiveness of conservative management when applied proactively. Future studies with larger sample sizes and longer follow-up are warranted to refine predictive models, optimize postoperative protocols, and further improve patient outcomes following thyroidectomy.

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