Secondary hyperparathyroidism (SHPT) in chronic kidney disease often necessitates parathyroidectomy (PTX), but this definitive treatment can precipitate hungry bone syndrome (HBS)—a profound, prolonged hypocalcemia caused by the rapid skeletal uptake of minerals after surgery. HBS results from the abrupt cessation of parathyroid hormone (PTH)-driven bone resorption while bone formation continues, leading to intensive mineral deposition (mainly calcium) into chronically demineralized bone. Clinically, HBS ranges from asymptomatic biochemical disturbances to life-threatening hypocalcemia with tetany, seizures, and/or cardiac arrhythmias. This illustrative review synthesizes current knowledge of HBS pathogenesis and management in the context of SHPT. We detail how the high-turnover bone remodeling state of SHPT (osteitis fibrosa cystica) creates an expansive unmineralized osteoid pool that avidly mineralizes post-PTX. We also explore molecular mechanisms (e.g., RANKL/OPG dysregulation, Wnt/β-catenin activation, osteocyte-driven signals, and calcium-sensing receptor effects) that underpin this process. Key preoperative risk factors for HBS include very elevated PTH and alkaline phosphatase levels, large skeletal calcium deficits, younger patient age, and total PTX. We outline the typical postoperative course of HBS, phased from immediate acute hypocalcemia to a nadir and gradual recovery. Prevention and management strategies are emphasized, centered on vigilant monitoring and aggressive calcium and calcitriol supplementation, with preoperative optimization (e.g., vitamin D loading, calcimimetics) to mitigate severity. By enhancing risk stratification and perioperative care, clinicians can improve outcomes and safely navigate patients through this challenging complication of endocrine surgery.

Background/Objectives: Secondary hyperparathyroidism (SHPT) affects 30–50% of end-stage renal disease patients. Parathyroidectomy (PTX), while effective for medication-refractory SHPT, carries 20–70% risk of hungry bone syndrome (HBS)—severe sustained hypocalcemia requiring intensive care and prolonged hospitalization. Accurate preoperative risk stratification using biochemical markers and validated prediction tools is critical for optimal preventive management. Methods: We conducted a comprehensive narrative review synthesizing evidence on HBS predictors after PTX in SHPT, evaluating traditional and novel bone turnover markers, clinical risk factors, and multivariate prediction models, through a structured literature search and analysis. Results: Preoperative bone turnover status represents the strongest contributor to HBS risk. Traditional biomarkers—particularly parathyroid hormone (PTH > 1000–2400 pg/mL) and alkaline phosphatase (ALP > 150–300 U/L)—demonstrate moderate-to-strong individual predictive power. Novel bone turnover markers (bone-specific ALP, P1NP, TRAP-5b) offer incremental value, especially in CKD populations where renal clearance affects traditional markers. Combined risk prediction models substantially outperform single biomarkers, achieving area under curve values of 0.87–0.95. The simple NYU 2-point score (ALP > 150 U/L + PTH > 1000 pg/mL) showed 96.8% accuracy, with 100% negative predictive value. More complex tools like nomograms (C-index 0.92–0.94) and machine-learning algorithms (AUC 0.88) provide enhanced discrimination by integrating multiple continuous parameters. Additional clinical factors—younger age (<48 years), prolonged dialysis (≥5 years), low preoperative calcium, high gland weight, and absence of autotransplantation—further refine risk assessment. Postoperative calcium typically reaches nadir at 48–72 h, defining the critical monitoring window. Conclusions: High-turnover bone biomarkers and combined risk models effectively identify high-risk SHPT patients. Risk-stratified protocols (i.e., prophylactic supplementation, intensive monitoring, and selective ICU admission) can substantially reduce HBS-related morbidity. Ongoing efforts should focus on validating these predictive tools across diverse populations and integrating them into clinical practice, thereby facilitating real-time HBS risk assessment and protocol-driven care.

Background/Objectives: Secondary hyperparathyroidism (SHPT) is a prevalent complication in end-stage renal disease, often necessitating surgical intervention when refractory to medical therapy. The optimal surgical strategy—subtotal parathyroidectomy (SPTX) versus total parathyroidectomy with/without autotransplantation (TPTX ± AT)—remains debated, especially considering postoperative complications like persistent HPT and hungry bone syndrome (HBS). This study aimed to compare early surgical outcomes and identify predictors for postoperative complications in patients undergoing SPTX and TPTX + AT. Methods: We conducted a retrospective, single-center observational study involving 93 dialysis patients who underwent PTX for drug-refractory SHPT. Patients were analyzed according to surgical procedure (SPTX vs. TPTX + AT), focusing on postoperative complications such as cervical bleeding, reintervention rates, and the incidence of HBS. Multivariate logistic regression was utilized to identify predictors of these outcomes. Results: TPTX + AT demonstrated superior control of HPT, with significantly lower rates of reintervention compared to SPTX (7.1% vs. 23.5%, p = 0.037). However, TPTX + AT was associated with a higher incidence of HBS (57.1% vs. 35.3%, p = 0.039). Independent predictors of reintervention included absence of concomitant thymectomy, preoperative hypercalcemia, fewer visualized glands preoperatively, and preoperative PTH > 2000 pg/mL. Elevated alkaline phosphatase levels (>300 U/L), severe bone pain, and the TPTX procedure itself were significant predictors of HBS. Conclusions: Surgical strategy for SHPT should be individualized, balancing the lower recurrence risk associated with TPTX + AT against its higher likelihood of postoperative hypocalcemia. Preoperative biochemical markers and clinical features could potentially influence operative decision-making and optimize patient outcomes.

Background and Aims: Severe acute respiratory distress syndrome (ARDS) in patients with long COVID remains associated with extremely high mortality and significant long-term sequelae. Non-invasive ventilatory strategies such as continuous positive airway pressure (CPAP) and high-flow nasal cannula (HFNC) are widely used before endotracheal intubation (ETI). Still, their comparative effectiveness in this population is not well established. Understanding survival outcomes and sequelae can help refine treatment strategies for this high-risk group. This study aimed to evaluate outcomes, sequelae, and treatment strategies in long COVID patients with severe ARDS, focusing on non-invasive ventilatory support before ETI. Materials and Methods: A retrospective cohort analysis was performed using a study comparing severe ARDS patients with and without COVID-19. The inclusion criterion was a Horovitz quotient (PaO₂/FiO₂) < 50 mmHg. Results: The study included a total of 59 patients diagnosed with long COVID-19 ARDS, with a mortality rate of 85%. A significant proportion of the patient population was male, accounting for 75%. The highest survival rate was observed among patients who initially received CPAP support, with a survival rate of 23.08%, in contrast to those treated solely with HFNC or those who alternated between HFNC and CPAP. Among patients who required endotracheal intubation and subsequent mechanical ventilation, survival rates were 40% for those who had previously received CPAP, 10% for those treated with alternating HFNC and CPAP, and 0% for those managed exclusively with HFNC before ETI. Survivors often exhibited sequelae, such as impaired pulmonary function, persistent dyspnea, and diminished physical performance. Conclusions: Patients with long COVID who develop severe ARDS (PaO₂/FiO₂ < 50 mmHg) face exceptionally high ICU mortality, with outcomes determined mainly by age, comorbidities, and profound hypoxemia. Although CPAP showed a trend toward improved survival, the data do not establish superiority and should be regarded as hypothesis-generating. Rather, they highlight the complexity of managing this underrepresented subgroup and underscore the need for larger, multicenter studies with broader inclusion criteria to confirm or refute these preliminary observations.