Calcineurin inhibitor-related hyperkalemia is caused by hyporeninemic hypoaldosteronism and fludrocortisone is an effective treatment: Report of a case series and review of the literature.

INTRODUCTION: Calcineurin inhibitors (CNIs) are widely used in transplantation. Although CNI-related hyperkalemia is common (10%-60.6%), the underlying pathogenetic mechanism is not well-elucidated and may lead to dose adjustment or treatment withdrawal. OBJECTIVE: The aim of this study is to describe CNI-related hyperkalemia due to hyporeninemic hypoaldosteronism in pediatric transplant recipients who were successfully treated with fludrocortisone. METHOD: In a total of 55 hematopoietic stem cell (HSCT) and 35 kidney transplant recipients followed according to institutional immunosuppression protocols, recipients diagnosed with CNI-related hyperkalemia were reviewed. Recipients who were receiving intravenous fluid, potassium, or were diagnosed with hemolysis, acute graft rejection, or had an eGFR < 30 mL/min/1.73m2, were excluded. A detailed analysis of clinical history as well as biochemical studies was carried out to reveal possible pathophysiology. RESULTS: Three pediatric transplant recipients (one HSCT, two kidney transplantation) with findings of hyperkalemia, hyponatremia, and a mild elevation in blood urea nitrogen while on CNIs were recruited. Urinary potassium excretion was diminished while sodium excretion was increased. Plasma aldosterone levels were low, and renin was not increased in response. Primary adrenal insufficiency was ruled out, and hyporeninemic hypoaldosteronism was diagnosed. CNI-related hyperkalemia was detected earlier in case 1, who had HSCT (22 days), than in the second and third cases, who had kidney transplantation (24 and 30 months post-transplantation, respectively). The discrepancy was hypothesized to be explained by higher overall CNI dose due to higher serum target CNI used in HSCT than kidney transplantation. Electrolyte imbalance was reversed upon administration of physiologic dose fludrocortisone (0.05 mg, daily), while fludrocortisone was ceased after CNI withdrawal in case 1, which is additional evidence for the etiological association of CNIs and hyporeninemic hypoaldosteronism. CONCLUSION: Our three cases strengthen the premise that CNI-related hyperkalemia may be due to hyporeninemic hypoaldosteronism, and the timing and severity may be related to CNI dose. Fludrocortisone is a safe and effective treatment in CNI-related hyperkalemia, providing maintenance of CNIs, which are one of the essential therapeutic agents for pediatric transplantation.

COVID-19 vaccination among adolescents and young adults with chronic kidney conditions: a single-center experience.

BACKGROUND: Following the pandemic of COVID-19, the main focus has been on COVID-19 vaccines and herd immunity. Although the safety of the COVID-19 vaccines has been shown in clinical trials, children with chronic diseases were not included. We investigated the side effect profile and safety of the COVID-19 vaccines in adolescents with kidney disease. METHODS: A questionnaire including demographic information, history of COVID-19, vaccination status, and vaccine-related side effects was administered to the patients with chronic kidney disease (CKD) stage 2-5, glomerular disease treated with immunosuppression, and kidney transplant recipients. RESULTS: Ninety-eight patients were vaccinated with CoronaVac-inactivated SARS-CoV-2 (n=16) or BNT162b2 messenger RNA (mRNA) COVID-19 (n=82) vaccine. The mean age was 16.90±2.36 years. The most common side effects were local pain, fatigue, and fever. No serious side effects or renal disease flare were observed. There was no significant difference in the side effects reported after the BNT162b2 mRNA-RNA as compared to the Corona Vac-inactivated SARS-CoV-2 vaccine. No significant relationship was found between the frequency of side effects according to age, glomerular filtration rate, immunosuppressive treatments, CKD stage, and the underlying disease. CONCLUSION: Although the reported data are subjective because they were obtained through a questionnaire and studies with long-term follow-up are needed, our early experience suggests that the vaccine is safe and adolescents and young adults should be encouraged to be vaccinated.

COVID-19 in Children with Chronic Kidney Disease; Does it Differ Much?

BACKGROUND: COVID-19 is known to have a mild course in children, however more data on pediatric chronic kidney disease (CKD) is needed. We aimed to assess the incidence and severity of COVID-19 in pediatric CKD patients. METHODS: A questionnaire including demographics, COVID-19 history, symptoms, and vaccination status was applied to patients with CKD. We also retrospectively reviewed the presentation and outcomes of SARS-CoV-2 infection in this patient group from March 2020 to December 2021. RESULTS: 220 patients were included, 48 were found to have experienced COVID-19. There was no significant difference regarding age, gender, underlying kidney disease, CKD stage, dialysis status, type or number of immunosuppressive medications, and glomerular filtration rate between patients with and without COVID-19. Most were infected by a household member (43.8%) and during outpatient or inpatient care (18.8%). Four (8.3%) were asymptomatic, and 43 (89.6%) had mild infection. Severe COVID-19 was observed in only one patient. Eleven (22.9%) patients with COVID-19 were previously vaccinated. Acute kidney injury was detected in 4 (8.3%); as stage 1 in all. Median follow-up after COVID-19 was 4.6 months. All patients fully recovered, and no renal disease flare or death was observed. CONCLUSIONS: Although the vaccination rate was low in our cohort, the majority of the children with COVID-19 showed a mild course. Along with the vaccination, general precautions seemed to be successful for this population.

Acute kidney injury in children with moderate-severe COVID-19 and multisystem inflammatory syndrome in children: a referral center experience.

BACKGROUND: Data on the characteristics of acute kidney injury (AKI) in pediatric COVID-19 and MIS-C are limited. We aimed to define the frequency, associated factors and early outcome of AKI in moderate, severe or critical COVID-19 and MIS-C; and to present a tertiary referral center experience from Türkiye. METHODS: Hospitalized patients ≤ 18 years of age with confirmed COVID-19 or MIS-C at Ihsan Dogramaci Children's Hospital, Hacettepe University, between March 2020-December 2021 were enrolled. The characteristics of AKI in the COVID-19 group were investigated in moderate, severe and critically ill patients; patients with mild COVID-19 were excluded. RESULTS: The median (Q1-Q3) age in the COVID-19 (n = 66) and MIS-C (n = 111) groups was 10.7 years (3.9-15.2) and 8.7 years (4.5-12.7), respectively. The frequency of AKI was 22.7% (15/66) in COVID-19 and 15.3% (17/111) in MIS-C; all MIS-C patients with AKI and 73.3% (11/15) of COVID-19 patients with AKI had AKI at the time of admission. Multivariate analyses revealed need for vasoactive/inotropic agents [Odds ratio (OR) 19.233, p = 0.002] and presence of vomiting and/or diarrhea (OR 4.465, p = 0.036) as independent risk factors of AKI in COVID-19 patients; and need for vasoactive/inotropic agents (OR 22.542, p = 0.020), procalcitonin and ferritin levels as independent risk factors of AKI in the MIS-C group. Age was correlated with lymphocyte count (r = -0.513, p < 0.001) and troponin level (r = 0.518, p < 0.001) in MIS-C patients. Length of hospital stay was significantly longer in both groups with AKI, compared to those without AKI. Mortality was 9.1% in the COVID-19 group; and was associated with AKI (p = 0.021). There was no mortality in MIS-C patients. AKI recovery at discharge was 63.6% in COVID-19 survivors and 100% in MIS-C patients. CONCLUSIONS: Independent risk factors for AKI were need for vasoactive/inotropic agents and vomiting/diarrhea in moderate, severe or critical COVID-19 patients; and need for vasoactive/inotropic agents and severe inflammation in MIS-C patients. Our findings suggest that inflammation and cardiac dysfunction are associated with AKI in MIS-C patients; and the association with age in this group merits further studies in larger groups. Early outcome is favorable; long-term follow-up for kidney functions is needed.

Hemoglobin cast nephropathy: a rare but serious complication of hemolysis in a pediatric patient.

BACKGROUND: Intravascular hemolysis is a serious and rare condition in children and causes the release of hemoglobin and heme into circulation, which have proinflammatory properties. These substances lead to inflammation, oxidative stress, apoptosis, and organelle dysfunction that lead to acute kidney injury (AKI). We report a pediatric case diagnosed with hemolysis-associated hemoglobin cast nephropathy due to autoimmune hemolytic anemia. CASE: A 4-year-old boy, who was admitted to another hospital with complaints of fever and dark urine for one day, developed anemia and kidney failure in the follow-up, was referred to our hospital. In physical examination, pallor and icterus on the sclera were noted. The patient had low hemoglobin and haptoglobin levels concomitant with high levels of serum lactate dehydrogenase, urea and creatinine. A peripheral blood smear showed marked spherocytes without schistocytes. A kidney biopsy was performed due to ongoing overt hemolysis and dialysis requirement, which showed findings consistent with hemoglobin cast nephropathy. Although the initial polyspecific direct antiglobulin test (DAT) was negative, due to persistent intravascular hemolysis DAT was studied monospecifically and showed IgM antibody positivity. Therefore, a diagnosis of autoimmune hemolytic anemia was made, and corticosteroid treatment was started. Hemolysis immediately ceased and the need for erythrocyte transfusion and dialysis disappeared. CONCLUSIONS: Acute kidney injury associated with hemoglobin cast nephropathy is an extremely rare condition in childhood. Although the initial course is severe and potentially life-threatening, the prognosis is favorable with the treatment of the underlying cause and management of AKI. Therefore, pediatricians should be aware of this rare clinical entity during clinical practice.

Albuminuria is associated with 24-hour and night-time diastolic blood pressure in urinary tract infection with renal scarring.

BACKGROUND: We aimed to detect complications and associated risk factors in patients with renal scarring (RS) secondary to recurrent urinary tract infections (UTI). METHODS: Fifty patients with RS were compared with 25 patients without RS by means of, serum creatinine, 24- hour urinary creatinine clearance, and 24-hour urinary albumin levels. Office blood pressure (BP) examination and ambulatory BP monitoring (ABPM) were also performed. RESULTS: Vesicoureteral reflux was detected in 50 patients. Glomerular filtration rate (GFR) < 90 ml/min/1.73 m2 was observed in 5 patients with RS but in no patient without RS. Albuminuria was significantly higher in patients with bilateral RS and severe RS. Patients with albuminuria had a significantly lower GFR than those without. All patients with ambulatory hypertension (HT) were in the RS group, and 60% of those had isolated nocturnal HT. Compared to those without RS, patients with RS had significantly higher SDS values for all BP readings, 24-hour and nighttime systolic and diastolic BP loads with significantly lower systolic dipping. GFR was negatively correlated with diastolic BP SDS and diastolic BP load in patients with RS. Daytime diastolic BP load was significantly higher in those with severe RS than in those with mild RS. CONCLUSIONS: Isolated nocturnal HT could be an early sign of complications in RS of UTI. Albuminuria is related to increased BP and impaired renal function. Therefore, ABPM and assessing albuminuria should be a routine part of the follow-up. Diastolic BP elevations could be associated with worse outcomes in these patients.

Neurologic manifestations in children with COVID-19 from a tertiary center in Turkey and literature review.

BACKGROUND: Since December 2019, coronavirus disease 2019 (COVID-19) has become a global pandemic caused by highly transmissible severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although respiratory disease and multisystem inflammatory syndrome in children (MIS-C) are main clinical presentations in children, numerous neurological manifestations are being described increasingly. We aimed to investigate new onset neurological symptoms associated with SARS-CoV-2 in pediatric patients in order to establish a possible relationship as well as to understand the underlying pathophysiological mechanisms between SARS-CoV-2 infection and neurological findings. METHODS: We analyzed retrospectively children who had neurologic manifestations temporally associated with SARS-CoV-2 infection at Hacettepe University Ihsan Dogramaci Children's Hospital. We performed a literature search between March 20, 2020 and March 30, 2021. Articles that report children with COVID-19 related neurological manifestations were included. RESULTS: We have observed 15 consecutive cases with new onset neurological manifestations along with confirmed SARS-CoV-2 infection. Age at hospitalization ranged from three months to 17 years. Ten patients had central nervous system involvement, and most common manifestation was encephalopathy (5/10), which is also one of the most common manifestations of the patients mentioned in the relevant 39 articles we reviewed. CONCLUSION: Children with COVID-19 can present with neurologic findings such as encephalopathy, seizures, cerebrovascular events as well as abnormal eye movements. Clinical suspicion and awareness are required to show the association between neurologic manifestations and COVID-19.

Apparent mineralocorticoid excess: A diagnosis beyond classical causes of severe hypertension in a child.

A genetic defect of 11 ß-hydroxysteroid dehydrogenase causes apparent mineralocorticoid excess syndrome. Since 50 days of life, our patient was hospitalized several times for various reasons including hypokalemia. At the age of 3.3 years, she was diagnosed with severe hypertension (160/120 mmHg). She also had left ventricular hypertrophy and hypertensive retinopathy and referred to our center. Her renal function and electrolytes were normal except for hypokalemia. She was on captopril treatment; nifedipine and propranolol were added. Plasma renin and aldosterone concentrations were 1.13 pg/ml (1-8.2 pg/ml) and 12.2 ng/dl (35-300 ng/dl), respectively. Severe hypertension, hypokalemia, low renin and aldosterone levels pointed to the diagnosis of apparent mineralocorticoid excess syndrome. Strict salt-restricted diet and potassium citrate were ordered. Genetic analysis of the HSD11B2 gene showed c.623G>A (p.Arg208His). Spironolactone was initiated. On follow-up, amiloride was added and her blood pressure was controlled. In patients with severe HSD11B2 mutation, combination therapy of spironolactone with amiloride could be effective in controlling blood pressure.

Severe hyponatremia and repeated intestinal resections for intestinal dysmotility mimicking congenital aganglionic megacolon due to delay in the diagnosis of congenital hypothyroidism.

Congenital hypothyroidism (CH) may present with nonspecific signs and symptoms, though, majority of infants can be asymptomatic. Therefore, understimation and delay in diagnosis may result in severe complications. A 5-month-old female admitted to our clinic with the history of repeated surgical operations due to the diagnosis of congenital aganglionic megacolon. Investigations performed in our clinic revealed the diagnosis of congenital (primary) hypothyroidism due to thyroid agenesis. Histopathologic evaluation of previously resected colon sample revealed normal ganglionic cell included colon. During follow-up she developed severe hyponatremia with a plasma sodium level of 106 mEq/L. Eunatremia was maintained following achievement of euthyroid state. In conclusion, since presenting symptoms can be variable and nonspecific, hypotyhroidism should be kept in mind in the differential diagnosis of patients with persistent abdominal distention mimicking aganglionic megacolon and severe hyponatremia of unknown origin.