Inflammation of the kidney parenchyma and the renal pelvis
This is usually due to bacterial infection
Highest incidence in women aged 15-29
Classifications of pyelonephritis
Uncomplicated = structurally or functionally normal in a non-immunocompromised host
Complicated = opposite
Neutrophils infiltrate the tubules and the interstitium
This leads to suppurative inflammation.
You can often see small renal cortical abscesses and streaks of pus in the renal medulla.
How does bacteria get to the kidneys?
Bacteria can reach the kidney either by ascending from the lower urinary tract, or directly by blood stream like septicaemia or infective endocarditis.
It can also rarely be via lymphatics like in retroperitoneal abscess
E. coli (80%)
Obstructed urinary tract and BPH
Spinal cord injury leading to neuropathic bladder
Indwelling catheter or ureteric stents and nephrostomy tubes in-situ
Structural renal abnormalities like vesicoureteric reflux.
DM, corticosteroid use, HIV infection
Renal calculi, sexual intercourse and menopause
Classic triad = fever, unilateral loin pain and N+V
This typically develops over the course of 24-48h
Patients may also have symptoms of co-existing lower UTI with freq, urgency and dysuria
There may also be visible or non-visible haematuria
Often look unwell
Features of sepsis
Unilateral or bilateral costovertbral angle tenderness and or suprapubic tenderness
Also assess the patient's fluid status and measure any post-void residual volumes.
Lower lobe pneumonia
Urinalysis for nitrites and leucocytes
Urinary beta-hCG for all women of child-bearing age.
Routine bloods with FBC and CRP
All cases should have renal USS to see if there is any obstruction.
If there is obstruction suspected (such as dilation) -> non-contrast CT imaging (CT-KUB) should be done.
A-E assessment and appropriate resus.
Start empirical abx based on local protocols (in leicester co-amoxiclav orally for 14 days or ciprofloxacin if pen allergic)
If there is N+V give IV instead.
This should be started as culture are sent off.
Management of severe or non-responding cases
Catheterisation and high-dependency unit monitoring.
Consider early CT imaging in such cases to check for any obstruction and complication of pyelonephritis like pyonephrosis or perinephric abscess.
Renal scarring -> CKD
What is chronic pyelonephritis?
Repeated infections can lead to chronic Py.
This in its turn leads to fibrosis and will ultimately destroy the kidney.
When is it more common to get chronic Py?
In obstructed systems like strictures in UTI, VUR or other anatomical abnormalities which leads to urinary reflux.
Diagnosis of chronic Py.
Usually radiologically where you can see a small scarred and shrunken kidney.
In what group of people is chronic Py more common?
Structural abnormalities of kidneys
More common in children and they often present asymptomatically or with first presentation being CKD.
Management of chronic Py.
Reverse any underlying cause
Optimise renal function
Consider prophylactic abx
Explain Emphysematous Pyelonephritis
A rare and severe form of acute pyelonephritis.
It is caused by gas-forming bacteria and is associated with a high mortality rate.
Clinical presentation of Emphysematous Pyelonephritis
Similar to acute pyelonephritis
Fail to respond to empirical IV abx
CT imaging will show evidence of gas within and around the kidney.
When is Emphysematous Pyelonephritis more common?
High glucose allows CO2 production from fermentation by enterobacteria
Management of mild Emphysematous Pyelonephritis
Management of severe Emphysematous Pyelonephritis
Nephrostomy insertion or percutaneous drainage of any collections present
Sometimes nephrectomy will be required.