Changes in vitamin D metabolites at the time of critical illness and 6 months later-A prospective observational study.

BACKGROUND: Despite multiple studies suggesting that low 25(OH)D-vitamin levels are associated with worse outcomes in critically ill individuals, attempts to mitigate the outcomes by fixed dose enteral supplementation unguided by baseline or target blood levels have been unsuccessful. Since a single measurement of 25(OH)D may not optimally reflect an individual's vitamin D status, we studied the plasma concentration of different vitamin D metabolites and their recovery during and following resolution of acute critical illness. METHODS: A prospective observational study including patients 18 years and older admitted to a mixed medical-surgical ICU in Reykjavik, Iceland, located at a high-northern altitude (64° N). Vitamin D metabolites were measured at three timepoints; On admission (S1), 3-5 days following admission (S2) and after recovery from acute illness (median 178 days) (S3). Concentrations of total 25(OH)D-vitamin, cholecalciferol (D3 ), total 24,25(OH)D-vitamin, vitamin D binding protein (VDBP) were measured with LC-tandem mass spectrometry (LC-MS/MS) and free 25-(OH)D was measured with enzyme-linked immunosorbent assay. RESULTS: Most individuals were vitamin D deficient when assessed during critical illness, with 25(OH)D-vitamin levels under 30 ng/ml for 37/40 individuals at timepoint S1 and 34/38 at S2. After recovery, 18/30 patients were deficient at S3. Levels of all vitamin D metabolites measured were low during critical illness but rose substantially following resolution of acute illness. No strong correlation was found between markers of acute illness severity or duration and resolution of vitamin D metabolites in the interval between acute illness and recovery. CONCLUSIONS: In critically ill patients, levels of multiple vitamin D metabolites are low but substantial recovery occurs following resolution of acute illness. It is unclear whether a single metabolite is sufficient to assess vitamin D status of critically ill patients and guide potential supplementation.

Assessment and therapy of selected endocrine disorders.

Diabetes remains the most commonly encountered endocrinopathy with the incidence of type 2 doubling in the past decade. The prevalence of diabetes is projected to continue to increase dramatically over the next several decades unless major public health initiatives are successful in stemming this growth. Both type I and 2 diabetics more frequently require surgical and critical care than their non-diabetic counterparts. Type 1 and 2 diabetics also sustain greater peri-operative morbidity and mortality. Careful preoperative assessment and appropriate perioperative intervention may limit this. There is increasing evidence that maintenance of normal blood glucose in the perioperative period and during critical illness is beneficial for diabetic and non-diabetic patients. More data will hopefully be forthcoming to substantiate recent reports and identify the mechanisms of improved outcome. Thyroid disease remains a commonly encountered pathology that is more readily identified and controlled in the modern era of radioimmune assays of thyroid hormone and successful medical and surgical therapies. Severe hypothyroidism and thyroid storm are associated with significant increases in perioperative morbidity and mortality. Recognition of these entities or those at risk for developing them post operatively is crucial in initiating timely and effective therapy. Primary Al is uncommon, but results in glucocorticoid and mineralocorticoid deficiency. Tertiary Al is far more common, most often secondary to iatrogenic therapy with exogenous glucocorticoids for the management of chronic diseases such as connective tissue disorders, anti-rejection regimes, and severe asthma. Glucocorticoid replacement or supplementation is needed on a case-by-case basis and should be individualized based on chronic steroid dose, duration, and stress of the surgical procedure. Perioperative steroid dosing regimes now recommend lower doses for shorter periods than previously suggested. More recently Al has been recognized in two populations, elderly patients undergoing major surgery and a subgroup of patients with septic shock. Timely diagnosis using synthetic ACTH stimulation testing and stress glucocorticoid, and possibly mineralocorticoid therapy, seems to reverse these processes and improve recovery. Although uncommon, patients with pheochromocytoma who undergo open or laparoscopic resections remain diagnostic and therapeutic challenges. Perioperative outcome seems to have improved, in part, related to newer therapies and less invasive surgeries when indicated. The appropriate preoperative assessment and management of patients with various endocrinopathies is important to optimize outcome and limit avoidable complications. Hopefully additional evidence based guidelines will be forth-coming particularly in caring for the ever increasingly encountered perioperative diabetic.