We describe an infant with holoprosencephaly, who developed polyuria and hypernatremia shortly after birth and was subsequently diagnosed with congenital central diabetes insipidus. Initially, fluid and electrolyte balance was managed solely through adjustments in fluid intake. However, at one month of age, the patient developed transient syndrome of inappropriate antidiuretic hormone secretion (SIADH), thereafter subsequently experiencing recurrent fluctuations in serum sodium levels due to SIADH. At two months of age, oral desmopressin was introduced to control polyuria. This treatment consequently attenuated hyponatremia during SIADH episodes. Although holoprosencephaly is a recognized cause of central diabetes insipidus, the occurrence of transient SIADH due to hypothalamic dysfunction is rare, and reports addressing therapeutic strategies for this condition are limited. Even in early infancy, the appropriate use of desmopressin lead to stable systemic management by reducing the risk of hyponatremia, allowing transition to home-based care.

Centrifugal therapeutic plasma exchange (cTPE) enables plasma removal at lower blood flow rates and can be performed using peripheral vascular access (VA), potentially reducing the invasiveness of plasma exchange in pediatric patients. We report four cases of intravenous immunoglobulin (IVIG)-resistant Kawasaki disease (KD) successfully treated with cTPE between illness days 8 and 12. All procedures were performed using peripheral VA under local anesthesia and continuous sedation with propofol. All sessions were performed with red blood cell (RBC) priming. Five-percent albumin was used as the sole replacement fluid, and the exchange volume was set at 1.0–1.5 times the estimated plasma volume. All patients completed 2–4 sessions without major complications or need for intubation. One patient developed transient coronary dilatation that regressed, whereas the remaining 3 had no coronary artery lesions. The median blood flow rate and treatment duration were 2.3 (1.8–2.8) mL/kg/min and 93 (69–118) minutes, respectively, with median reduction rates of immunoglobulin G (IgG) and fibrinogen of 67.3% and 66.8%. No clinically significant hypocalcemia or thrombocytopenia occurred. These findings suggest that cTPE using peripheral VA can be safely and effectively performed in patients with IVIG-resistant KD, offering a less invasive and feasible alternative to membrane TPE, which has been the predominant modality in Japan.