Small UTI/PyeloN diagnosed with CKD. GP thinks main issue still undetected.

[KidneySOS]

Hey Community, thank you for sharing. I need your help in assessing if I have been misdiagnosed or under-diagnosed and if I should get checked for something else causing CKD(chronic kidney disease). Because of bilateral symmetrical involvement of kidneys, and prompt treatment of Acute Pyelonephritis that has not led to good recovery in kidney health, my general physician thinks there could be something else causing this, or some other advanced treatment that could be more effective.

Background: Acute onset of pyelonephritis(creatinine > 5, TLC >12500, Pus Cells > 120) diagnosed in Dec 2015. Under hospitalization for 2 weeks with drip antibiotic regimen. Followed by a re-admit to hospital with high fever and change of antibiotic. Chest X-Ray, ANA, Blood TB negative. Bilateral symmetrical involvement of both kidneys.  6 month regimen of cocktail of antibiotics. Creatinine stayed close to 4.0 for 6 months, then shot up to 5.43 within 3 weeks in July. GFR of 14.69. Diagnosis of CKD/CGN/HTL in July. Pre-dialysis prep recommended.

BP patient for last 12-14 years. 71 years old. Take regular BP medicine. No other chronic issues. 2010 Creatinine test came back at 0.80 (Normal). No other creatinine tests done till Dec 2015. Unclear why recovery in kidney function is poor after quick administration of Pyelonephritic treatment, and why there is bilateral symmetrical involvement.

Any other diagnosis?? or suggested course of action?
(Currently on long term antibiotic, and kidney support and BP management medicines. Due for Fistula implant)

I appreciate any help.