VARIED MANIFESTATIONS AND ASSOCIATIONS OF LEPTOSPIRA AKI - CLINICAL AND HISTOPATHOLOGICAL ANALYSIS.

7 Feb 2025 12 a.m. 12 a.m.

WCN25-AB-3928, Poster Board= FRI-028

Introduction:

Leptospirosis is a zoonosis (reservoir rat) caused by Leptospira interrogans obligate aerobic spirochete (1). Human transmission occurs by contact with the blood, or urine of infected animals (2-4). First phase of disease is associated with leptospiraemia whereas second phase is mediated immunologically. Acute interstitial nephritis (AIN) is most common cause of acute kidney injury (AKI) in leptospirosis. Pauci-immune crescentic glomerulonephritis (CrGN) with AIN or AIN with crescents are not reported. Occasional cases of vasculitis have been reported (5,6). Several antibodies, Antiphospholipid, ANCA has been reported to be positive(7); the role of these antibodies in pathogenesis of AKI is not clear.

Here we report autoimmune manifestation and biomarkers associated with Leptospira and AKI in nine cases along with renal histopathology findings in five patients.

Methods:

Medical record analysis of Patients admitted between 1st August to 14th September 2024 with Leptospiral illness (IgM Leptospira positive) and AKI were done. AKI was defined as per KDIGO guidelines. Real time ultrasound guided renal biopsy was done using 18G needle. Light microscopy and IF was done.

Results:

AIN

Crescntic GN

Crescnts with AIN

The mean age was 51years; 55%were male. co-morbidities & auto immune manifestations are mentioned in table-1. On admission median BP was 146.7/88 mm hg (median); None had shock. All patients had ARDS. Non-cardiogenic in three with pulmonary infiltrates on imaging. Leucocytosis with neutrophilia and lymphopenia was common. LFT derangement was uncommon. C-ANCA was positive in 02 patients; Anti GBM in one patient. All patients were in stage –III AKI. Urine output (non oliguric/oliguria) and proteinuria correlated with biopsy findings. Non-oliguric in patients with AIN and renal recovery; whereas glomerular injury was associated with poor recovery.

Patients who underwent Kidney biopsy, all showed AIN with dense lympho-mononuclear infiltration. Infiltrates also included neutrophils and plasma cells. (Fig-1) Patient with HBV infection also had two fibro-cellular crescents on biopsy(Fig-2); Patient with ANCA–C and P both positivity had crescentic (pauci-immune) GN with AIN, no linear staining or IgG deposition were seen despite along glomerular basement membrane, despite Anti GBM positivity in sera. (Fig-3). Electron microscopy was not done because of non-availability.

All patients were treated with doxycycline and meropenem for ten days. The patient with crescentic GN was pulsed followed by oral steroids.

Follow up and outcome - Three patient recovered AKI and four discharged on RRT. Whereas two died. One patient with crescents and AKI remained on RRT at one month. The patient with crescentic glomerulonephritis succumbed to pulmonary infection.

S.No	age	comorbidity	IgM Leptospira	Hb/TLC/N/L/Platelets	ALT	Sr.creat	Oliguric/Non	ANA/ANCA/Anti GBM	Kidney Biopsy	Outcome	Autoimmune manifestations
1	61/M	HTN- COPD	Positive	8.8/18.03/92/4.2/276	99.3	11.41	Oliguric	Negative	AIN	Discharged on RRT	Absent
2	22/M	Hepatitis B	Positive	5/16.7/79/14/518	10	15.79	Anuric	Negative	AIN with crescents	Discharged on RRT	Absent
3	43/F	DM/ Ketoacidosis	Positive	9.2/14.84/86/6.7/178	7.5	6.22	Non oliguric	Negative	AIN	Recovered AKD/ Discharged	Absent
4	40/M	CAD	Positive	9.8/6.9/65/22/58	64	12.77	Non oliguric	Negative	AIN	Recovered AKD/ Discharged	Thrombocytopenia
5	43/F	None	Positive	5.7/6.5/55/22/421	12.6	14.35	Oliguric	C-ANCA + Anti GBM+	Crescentic GN with AIN	Death	Absent
6	31/F	ckd 5D, HCV	Positive	5.8/9.5/86/8/265	82	7.66	Oliguric	Negative		Discharged RRT	Absent
7	54/F	Rheumatoid arthritis	Positive	6.7/22/90/6.8/750	4.8	6.39	Non oliguric	ANCA -C +		Discharged -partil recovery	Absent
8	63/M	HTN- CAD	Positive	13.2/12/72/24/227	74	10	Anuric	Negative		Death	GBS
9	56/M	None	Positive	9.7/20.8/90/5.6/112	18	11.99	Oliguric	Negative		Discharged on RRT	Reactive arthritis, Thrombocytopenia
Hb-Hemoglobin gm/dl;TLC-Total leucocyte count mm3;N-Neutrophils;L-Lymphocyte;ALT-Alaninine aminotransferase U/L;Sr creat-serum creatinine mg/dlHTN-Hypertension;CAD-Coronary artery disease

Conclusions:

Conclusion: AKI in leptospirosis due to acute interstitial nephritis has good outcome. Various autoimmune manifestations may be associated i.e. GBS, reactive arthritis, thrombocytopenia. Autoimmune biomarkers like P and C ANCA and Anti GBM may also be associated. The role of auto immune antibodies need to be explored further in pathogenesis of Leptospira AKI.

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.