Acute Pyelonephritis Flashcards
How common is it?
About 1 in 30 cases of UTI.
Who does it affect?
- In neonates it is 1.5 times more common in boys and tends to be associated with abnormalities of the renal tract.
- Uncircumcised boys tend to have a higher incidence than circumcised boys.
- Beyond the age of a year, girls have a higher incidence than boys.
- In adult life it reflects the incidence of UTI in that it is much more common in young women. Over the age of 65 the incidence in men rises to match that of women.
What causes it?
Usually same organisms that cause UTIs.
Risk factors?
- Structural renal abnormalities, calculi and urinary tract catheterisation, stents or drainage procedures, pregnancy, diabetes, primary biliary cirrhosis, immunocompromised patients, neuropathic bladder.
How does it present?
Symptoms
- Usually rapid with symptoms appearing over a day or two.
- Unilateral or bilateral loin pain, suprapubic or back pain.
- Fever is variable but can be high enough to produce rigors.
- Malaise, nausea, vomiting, anorexia and occasionally diarrhoea occur.
- There may or may not be accompanying lower urinary tract symptoms with frequency, dysuria, gross haematuria or hesitancy. Gross haematuria occurs in 30-40% of young women.
Signs
- The patient looks ill and there is commonly pain on firm palpation of one or both kidneys and moderate suprapubic tenderness without guarding.
Complications
- Septicaemia
- Perinephric abscess
- Acute papillary necrosis
- Pregnancy – significant risk of premature labour
- Pyelonephritis is more likely to scar the kidney of a growing child.
Conditions that may present similarly?
- Abdominal abscess, abdominal aortic aneurysm, appendicitis, causes of acute abdomen, causes of loin pain, diverticulitis, ectopic pregnancy, endometritis, epididymitis, interstitial cystitis, nephrocalcinosis, nephrolithiasis, oophoritis, papillary necrosis, pelvic inflammatory disease, prostatitis, renal corticomedullary abscess, renal vein thrombosis, salpingitis, sexually transmitted infections, ureteropelvic junction obstruction, urethritis, vesicoureteral reflux, vesicovaginal and ureterovaginal fistula.
Investigations?
- Urinalysis - urine often cloudy with an offensive smell. May be positive on dipstick urinalysis for blood, protein, leukocyte esterase and nitrite. A midstream specimen of urine (MSU) should be sent off for microscopy and culture, although there is often poor correlation between symptoms and bacteriuria. A catheter specimen will be acceptable if a catheter is in situ and special arrangements may be needed for collecting a sample from a child (eg, peroneal bag, suprapubic aspiration). Microscopy of urine shows pyuria.
- Inflammatory markers – CRP, ESR and plasma viscosity raised.
- FBC - ↑white cell count and neutrophilia.
- Blood cultures – positive in approx 12-20%.
- Imaging – Recommended in all but mandatory in those with recurrence to identify obstruction or stones. Contrast enhanced spiral/helical CT (CECT) is best investigation in adults. Dimercaptosuccinic acid (DMSA) scan is mainly used for detailed renal cortical views in recurrent cases, to detect scarring. MRI sometimes useful in detecting scarring.
- Renal biopsy occasionally used to exclude papillary necrosis.
Treatments?
Support
- Rest, adequate fluid intake and analgesia important.
Hospital admission: Indications for admission include:
Severe vomiting
Comorbidity such as diabetes
Signs of sepsis (eg, tachypnoea, tachycardia, hypotension)
Dehydration
Severe pain or debility
Failure of response to treatment in primary care
Urinary tract obstruction
Oliguria or anuria
Suspected complications (see ‘Complications’, below)
Uncertain diagnosis
Social issues
Non-concordance with treatment
Inadequate access to follow-up
Relapse of symptoms as soon as antibiotics have been stopped
Antibiotics – Empirical treatment = ciprofloxacin. Third generation cephalosporin is an alternative.
Surgery – May be required to drain renal abscesses or relieve obstructions causing infection.
