Sistemic calciphylaxis and thrombotic microangiopathy in a kidney transplant patient: two mixing fatal syndromes?

Abnormalities in calcium and phosphorus metabolism are common and metabolic bone diseases develop often in patients with chronic renal failure (CRF). Effective clinical management includes measures to control phosphorus retention and prevent hyperphosphataemia, to maintain serum calcium concentrations within the normal range and to prevent excess parathyroid hormone (PTH) secretion by the judicious use of vitamin D sterols. Certain of these interventions, however, appear to increase the risk of soft tissue and vascular calcification in patients with End Stage Renal Disease (ESRD), so current therapeutic approaches are thus being re-evaluated in an effort to limit these risks. Patients with calciphylaxis have an extremely high mortality rate, diagnosis requires a high degree of clinical suspicion and the role and extent of parathyroidectomy in the management of this condition remain controversial. In some cases renal transplant patients could suffer from a comorbidity in which vascular function is compromised not only by secondary hyperparathyroidism-related calcification but also by other pathological condition as haemolytic uremic syndrome (HUS), leading to a fatal clinical outcome. We postulate that in these cases a secondary hyperparathyroidism not properly diagnosed in an early phase of the renal disease (probably before the kidney transplant) could cause a vascular calcification which, adding to the pre-existing HUS-related vascular compromission, gave rise to catastrophic clinical consequences. In the management of ESRD patients, in particular in the cases of pre-existing angiopathies, could be therefore crucial the early and proper diagnosis of an alteration of calcium-posphorus metabolism and effort of medicine could be oriented in these cases also towards identification of screening methodologies to undoubtedly assess such a diagnosis.