Loin Pain Hematuria syndrome

[galyea123]

Hi! We received a request from a patient affected with this condition. As per my review most clinicians consider LPHS a diagnosis of exclusion, and its status as a distinct clinical entity with specific characteristics versus an umbrella term encompassing all cases of glomerular hematuria with pain remains unresolved. Some experts suggest that LPHS could simply represent a severe phenotypic expression of underlying glomerular disorders and research is hindered by the lack of standardized diagnostic criteria, reliance on exclusion-based diagnosis, and limited understanding of the underlying mechanisms. However, the argument about it being an independent condition is strong. It is based in that LPHS typically involves chronic or recurrent loin pain and intermittent gross or persistent microscopic hematuria without evidence of a systemic or progressive renal It is also not always associated with structural or histological abnormalities on biopsy, setting it apart from other glomerular disorders.
The proposed mechanisms suggesting LPHS is a distinct pain syndrome rather than a secondary manifestation of glomerular disease include:[1],[2],[3]

Renal nerve hypersensitivity or neuropathy.
Ischemic injury due to vascular abnormalities or microvascular dysfunction.
Aberrant pain signaling pathways independent of inflammation or structural kidney damage.
In summary, I am still trying to decide as LPHS likely sits at the intersection of these perspectives. It may be an independent entity in a subset of patients with specific pathophysiological features while serving as an umbrella term for patients whose conditions are not yet fully elucidated or understood. It also have being proposed that it may be a somatoform disorder [4] and other are proposing a genomic basis and researching that LPHS patients have either gain-of-function mutation of the pain pathways and/or a loss-of-function mutation in the pain dampening pathways.[5]
Please consider reviewing it for inclusion as a rare disease: (note that it is not in Orphanet - I did sent them a ticket too; it was included in GARD but it is not anymore)

See sources:

https://www.kidney.org.uk/loin-pain-haematuria-syndrome
https://www.uptodate.com/contents/loin-pain-hematuria-syndrome
https://www.kireports.org/article/S2468-0249(23)01477-8/fulltext
https://pmc.ncbi.nlm.nih.gov/articles/PMC10928983/
https://journals.sagepub.com/doi/pdf/10.1177/20543581231183856
Let me know your thoughts,
Best, Gioconda Alyea