Erkam Yıldırım

Objectives: Apparent mineralocorticoid excess (AME) syndrome is a rare monogenic disorder caused by loss-of-function variants in the HSD11B2 gene encoding 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2). Deficient enzyme activity results in cortisol-mediated activation of the mineralocorticoid receptor, leading to low-renin hypertension. Because affected infants frequently present with polyuria and hypokalemic metabolic alkalosis, AME syndrome is often misdiagnosed as Bartter syndrome, resulting in significant diagnostic delay. Case presentation: A 13-month-old girl presented with polyuria, hypokalemic metabolic alkalosis, hypercalciuria, and failure to thrive and was initially managed as Bartter syndrome. During follow-up, persistent hypertension accompanied by markedly suppressed plasma renin activity and aldosterone levels prompted evaluation for monogenic hypertension. Urinary steroid analysis demonstrated a markedly reduced cortisone-to-cortisol ratio (0.02), consistent with 11β-HSD2 deficiency. Next-generation sequencing of the HSD11B2 gene identified a homozygous likely pathogenic splice-site variant, c.665-1G>A, confirming the diagnosis of AME syndrome. Treatment with spironolactone, amlodipine, potassium supplementation, and dietary salt restriction achieved blood pressure control and improved electrolyte abnormalities. Conclusions: AME syndrome should be included in the differential diagnosis of infants presenting with hypokalemic metabolic alkalosis and polyuria, particularly when hypertension is detected. Systematic blood pressure assessment is essential in this clinical context, as early recognition of this monogenic disorder may prevent long-term cardiovascular and renal complications.

Herpes simplex virus (HSV) infection is common in solid organ transplant recipients due to viral reactivation under immunosuppression. We report a case of a 9-year-old renal transplant recipient who developed recurrent perioral HSV infection following discontinuation of antiviral prophylaxis. The patient presented with localized vesicular lesions without systemic symptoms, and each episode responded rapidly to oral antiviral therapy. However, recurrences occurred mainly during periods of increased immunosuppression, such as treatment for acute cellular rejection, or after cessation of prophylaxis, whereas no HSV-related episodes were observed during antiviral prophylaxis. Because of recurrent HSV episodes, long-term low-dose suppressive antiviral therapy was initiated. This case illustrates that HSV infection in pediatric renal transplant recipients may follow a recurrent course and underscores the importance of individualized management strategies given the uncertainty surrounding the optimal duration of prophylactic antiviral therapy.

Serum alkaline phosphatase concentration rises in some disease states. On the other hand, benign transient hyperphosphatasemia is most commonly recognized in infants and children younger than 2 years of age. It has also been described in adults. Benign transient hyperphosphatasemia is a self-limiting condition that is usually accompanied by some infectious and allergic disorders. Therefore it is important to keep this entity in mind to avoid unnecessary investigations. Here, we report two children who were diagnosed with benign transient hyperphosphatasemia following gastroenteritis.