Sydenham's Chorea: Is There a Hidden Risk to the Kidneys?
"New research suggests that children with Sydenham's chorea, a complication of rheumatic fever, may experience previously undetected kidney injury. Learn about the connection and what it means for long-term health."
Rheumatic fever, a complication of strep throat, can lead to a range of issues, including Sydenham's chorea (SC). SC is a neurological disorder characterized by involuntary movements, mainly affecting children. It's well-known that rheumatic fever can damage the heart, but new research is exploring its potential impact on other organs, specifically the kidneys.
Acute Rheumatic Fever (ARF) is a nonsuppurative complication of Group A ẞ-hemolytic streptococcal (GABHS) infection due to a delayed immune response. Sydenham's chorea (SC) is an important neurological manifestation of ARF, and heart involvement is seen in a large proportion of patients with SC. The immune system has a crucial role in initiating and spreading inflammation, which causes tissue damage in ARF.
A new study has investigated a potential link between SC and kidney injury, using a specific marker called neutrophil gelatinase-associated lipocalin (NGAL). NGAL is released by the kidneys when they are stressed or damaged. The goal was to determine if children with SC showed higher levels of NGAL, suggesting a possible, previously unrecognised, effect of rheumatic fever on kidney health.
The Link Between Sydenham's Chorea and Kidney Health: What the Study Found
The research involved twenty-eight children diagnosed with SC and evidence of valvular involvement. These were matched with 30 healthy children. Researchers performed cardiac evaluations and measured levels of urinary NGAL, micro-total protein, and creatinine levels in both groups.
- Elevated NGAL Levels: Children with SC showed significantly higher levels of NGAL in their urine compared to the control group (18.01 ± 7.9 vs. 3.22 ± 1.4, p = 0.002).
- Increased NGAL/Creatinine Ratio: The ratio of NGAL to creatinine was also significantly higher in the SC group (2.80 ± 1.9 vs. 0.33 ± 0.1, p = 0.008), indicating a greater degree of kidney stress relative to kidney function.
- Correlation with Valvular Regurgitation: The severity of valvular regurgitation (a heart valve problem) was positively correlated with both urinary NGAL (r = 0.751, p < 0.001) and the NGAL/creatinine ratio (r = 0.694, p < 0.001). This suggests that more severe heart involvement is linked to greater kidney stress.
What Does This Mean for the Future?
While the study provides valuable insights, it's important to remember that this was a single-center study with a limited sample size. More research is needed to confirm these findings and understand the long-term implications of this subclinical kidney injury.
The researchers suggest that future studies should focus on long-term follow-up of patients with ARF to monitor for potential kidney problems. Further research is needed to fully understand the relationship between the immune response, kidney health, and the development of chorea and carditis in ARF.
This study highlights the importance of considering the potential impact of rheumatic fever on multiple organ systems. Detecting subclinical kidney injury early could lead to interventions that prevent long-term kidney damage and improve the overall health of children with Sydenham's chorea.