Kidney Week

Abstract: FR-PO0853

Biopsy-Proven Renal Thrombotic Microangiopathy: A Large Middle Eastern Case Series

Session Information

• Glomerular Diseases: Practice and New Concepts Shaping Modern Care
  October 23, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Arabi, Ziad, King Abdulaziz Medical City in Riyadh, Riyadh, Riyadh Province, Saudi Arabia

Ziad Arabi, MD

• Algahtani, Fahad, King Abdulaziz Medical City in Riyadh, Riyadh, Riyadh Province, Saudi Arabia

Fahad Algahtani, MD

• Alanazi, Muhannad Azim, King Abdulaziz Medical City in Riyadh, Riyadh, Riyadh Province, Saudi Arabia

Muhannad Azim Alanazi, MBBS

• Alabdulsalam, Abdulrahman K., King Abdulaziz Medical City in Riyadh, Riyadh, Riyadh Province, Saudi Arabia

Abdulrahman K. Alabdulsalam, MBBS

• Aloudah, Nourah Mohamed, King Abdulaziz Medical City in Riyadh, Riyadh, Riyadh Province, Saudi Arabia

Nourah Mohamed Aloudah, MD

• Alawadh, Nayef, King Abdulaziz Medical City in Riyadh, Riyadh, Riyadh Province, Saudi Arabia

Nayef Alawadh, MBBS

Background

Renal thrombotic microangiopathy (TMA) is a rare and heterogeneous disorder associated with significant kidney morbidity. Data from the Middle East remain limited. We describe the clinical characteristics, pathology, treatment, and outcomes of biopsy-proven renal TMA at a tertiary care center.

Methods

We retrospectively reviewed 1,127 native kidney biopsies performed at King Abdulaziz Medical City between 2015 and 2026. Eighteen patients with biopsy-confirmed TMA were identified. Demographic, clinical, histopathological, treatment, genetic, and renal outcome data were analyzed.

Results

Eighteen patients with biopsy-proven TMA were identified (1.6% of native kidney biopsies), including 10 males (55.6%) and 8 females (44.4%), with ages ranging from 5–53 years. Common presentations included acute kidney injury in 12 patients (66.7%), fever in 8 (44.4%), nephrotic-range proteinuria in 7 (38.9%), hypertension in 6 (33.3%), generalized edema/volume overload in 6 (33.3%), diarrhea in 5 (27.8%), and preceding upper respiratory or gastrointestinal symptoms in 5 (27.8%). Hemodialysis was required in 10 patients (55.6%).
Underlying etiologies included SLE/antiphospholipid syndrome in 4 patients (22.2%), post-stem cell transplantation TMA in 2 (11.1%), pregnancy-related TMA in 1 (5.6%), malignancy/drug-associated TMA in 1 (5.6%), and unknown etiology in 5 (27.8%). No cases were associated with Shiga toxin infection.
Eight patients (44.4%) underwent genetic testing; one had a heterozygous CD46 mutation, one had a CFHR1 risk factor, and one had combined CFHR1/CFHR3 risk factors. Seven patients (38.9%) received eculizumab or ravulizumab. Among treated patients, 3 (42.9%) developed stable CKD, 2 (28.6%) underwent successful kidney transplantation without relapse, 1 (14.3%) achieved normal kidney function recovery, and 1 (14.3%) had partial renal recovery.
Overall, 5 patients (27.8%) progressed to ESRD, 5 (27.8%) developed persistent CKD, 4 (22.2%) recovered normal kidney function, and 2 (11.1%) died.

Conclusion

TMA is a heterogeneous disorder with variable presentation and renal outcomes. Prognosis appears influenced by the underlying etiology and severity of kidney injury. Genetic testing may identify complement-mediated disease in selected patients, while complement inhibition therapy may improve outcomes in eligible patients. Early recognition and targeted treatment remain essential.