Hypercalciuria in children with febrile convulsions

Temperature sensing by the calcium-sensing receptor

Whether GPCRs support the sensing of temperature as well as other chemical and physical modalities is not well understood. Introduction: Extracellular Ca²⁺ concentration (Ca²⁺ _o) modulates core body temperature and the firing rates of temperature-sensitive CNS neurons, and hypocalcemia provokes childhood seizures. However, it is not known whether these phenomena are mediated by Ca²⁺ _o-sensing GPCRs, including the calcium-sensing receptor (CaSR). In favor of the hypothesis, CaSRs are expressed in hypothalamic regions that support core temperature regulation, and autosomal dominant hypocalcemia, due to CaSR activating mutations, is associated with childhood seizures. Methods: Herein, we tested whether CaSR-dependent signaling is temperature sensitive using an established model system, CaSR-expressing HEK-293 cells. Results: We found that the frequency of Ca²⁺ _o-induced Ca²⁺ _i oscillations but not the integrated response was linearly dependent on temperature in a pathophysiologically relevant range. Chimeric receptor analysis showed that the receptor's C-terminus is required for temperature-dependent modulation and experiments with the PKC inhibitor GF109203X and CaSR mutants T888A and T888M, which eliminate a key phosphorylation site, demonstrated the importance of repetitive phosphorylation and dephosphorylation. Discussion and Conclusion: CaSRs mediate temperature-sensing and the mechanism, dependent upon repetitive phosphorylation and dephosphorylation, suggests that GPCRs more generally contribute to temperature-sensing.

The baseline risk of multiple febrile seizures in the same febrile illness: a meta-analysis

The baseline risk for multiple febrile seizures within the same febrile illness is largely unknown. Estimates range from 5 to 30%. Imprecise estimates can lead to incorrectly powering studies investigating the management of febrile seizures. To estimate the risk of multiple febrile seizures in the same febrile illness, we systematically reviewed and conducted a meta-analysis of studies from January 2000 to December 2021 that contained data for the number of children for both simple and complex febrile seizures in the same febrile illness. We searched MEDLINE, EMBASE, and Web of Science for randomized, quasi-randomized, prospective, and retrospective trials that involved children with febrile seizures. A total of 23,131 febrile illnesses with febrile seizures met the inclusion criteria. The estimated baseline risk of multiple febrile seizures in the same febrile illness was 17% (95% CI, 16-19%). However, the 30 cohorts that included both admitted and non-admitted patients had a lower percentage of multiple FSs within the same illness (14%; 95% CI, 12-15%) than the 30 cohorts that enrolled only admitted patients (20%; 95% CI, 16-25%).

CONCLUSION

Researchers can use estimates in this paper to design future studies. Taking into the account the substantial heterogeneity between countries and studies, clinicians could cautiously use our estimates in their clinical assessment and be better able to set parental expectations about a child's chances of having another febrile seizure during the current illness.

TRIAL REGISTRATION

PROSPERO CRD42020191784. Registered July 18, 2020.

WHAT IS KNOWN

• There is renewed interest in the diagnostic workup and prophylactic treatment of febrile seizures to prevent repeat seizures in the same febrile illness. • There is a lack of accurate estimates of the baseline risk for multiple febrile seizures in the same illness to properly design studies investigating management.

WHAT IS NEW

• This study provides the most robust estimates for the baseline risk for multiple febrile seizures in the same illness.

Hypercalciuria and febrile convulsion in children under 5 years old

Purpose

The association between hypercalciuria and febrile convulsion is controversial. The present study aimed to investigate the statistical association between hypercalciuria and childhood febrile convulsions.

Methods

Overall, 160 children aged 6 months to 5 years, including 80 children with febrile convulsion and 80 febrile children without convulsion (comparison group), were recruited. All laboratory tests, including 24-hour urine calcium, were undertaken in an academic clinical laboratory.

Results

Forty-five children of the febrile convulsion group (60%) and 30 of the comparison group (40%) had hypercalciuria. There was a significant difference between the 2 groups (P=0.02).

Conclusion

Our results indicated that there is a statistical association between convulsion and hypercalciuria in children. Since we found this association with a cross-sectional assessment, further studies, especially prospective and controlled designs, are needed.

Association of genetic polymorphism of pre-microRNA-146a rs2910164 and serum high-mobility group box 1 with febrile seizures in Egyptian children

Interaction between immune-inflammatory process and genetic factors might be implicated in the pathogenesis of febrile seizures. Pre-microRNA (miR)-146a rs2910164 polymorphism is postulated to modulate expression of miR-146a whose anti-inflammatory role involves regulation of high-mobility group box 1. Our aim is to examine whether rs2910164 polymorphism influences serum high-mobility group box 1 levels and whether an association exists between both and febrile seizures. The study included 136 children, divided into 4 groups. Real-time polymerase chain reaction was used for detection of rs2910164 polymorphism and high-mobility group box 1 was measured using enzyme-linked immunosorbent assay. High-mobility group box 1 levels were higher in febrile seizure patients compared to the other groups. Rs2910164 polymorphism was not associated with increased risk of febrile seizures. Rs2910164 polymorphism might be accompanied by an upregulation of the proinflammatory process as it might be associated with an increase in high-mobility group box 1 and leukocytic count.

Trace elements in febrile seizure compared to febrile children admitted to an academic hospital in iran, 2011

BACKGROUND AND AIM

Pathogenesis of Febrile Convulsion (FC) is unknown but some elements and genetic predispositions have been considered in the top list. This case-control study was designed to compare some trace elements in paediatrics who were admitted with FC and those in febrile ones without seizure attacks at an academic hospital in northeast of Iran.

MATERIAL AND METHODS

This case-control study was done from June 2010 to July 2011 on 160 paediatrics (6-months to 5-years old) who were diagnosed with FC and on 160 age-matched febrile children as control group. Data on the age, gender, past history of fever and convulsion, age at the first episode of seizure and family history of FC were gathered by using a designed checklist. Complete Blood Count (CBC), serum iron, Total Iron Binding Capacity (TIBC), zinc, magnesium and calcium were tested after taking informed consents from the parents. Serum levels of trace elements were measured by a photometric method. Independent t-test or non-parametric Mann-Whitney test were used to compare means between two groups.

RESULTS

There were no significant differences between the cases and controls with regards to the gender or age. TIBC and magnesium were lower in FC, but calcium, iron and zinc were higher in FC as compared to those in the other group (not significant).

CONCLUSIONS

So, it could be said that deficiency of trace elements was not significantly related to febrile convulsion in our study and it seemed that these tests were not necessary in FC cases. But further investigations on other trace elements are needed.

Studies on cerebrospinal fluid ionized calcium and magnesium concentrations in convulsive children

BACKGROUND

The concentrations of ionized calcium (iCa) and ionized magnesium (iMg) were measured in the cerebrospinal fluid (CSF) of convulsive and non-convulsive children, to investigate the relationship between seizure manifestation and CSF iCa and iMg concentrations. Standard concentrations of CSF iCa and iMg were also established.

METHODS

CSF samples from 23 patients, ages 0-15 years, with various forms of seizures and 26 age-matched non-convulsive children were collected by lumbar puncture. CSF was obtained anaerobically and the concentrations of CSF iCa and iMg were measured with an electolyte analyzer (Stat Profile Ultra M1, NOVA, USA) immediately after the lumbar puncture.

RESULTS

The concentrations of CSF iCa were significantly higher in non-convulsive children younger than 11 months old compared with children older than 12 months. The concentrations of CSF iMg in non-convulsive children did not differ significantly with aging. The concentrations of CSF iCa in convulsive children did not differ significantly from the concentrations of non-convulsive children. The concentrations of CSF iMg in convulsive children were significantly lower than in non-convulsive children.

CONCLUSION

These results suggest that seizure manifestation is related to age-dependent changes in iCa and decreased iMg in the developing brain.