Abstract
Introduction
Pyelonephritis is usually caused by ascent of bacteria, most often Escherichia coli, from the bladder, and is more likely in people with structural or functional urinary tract abnormalities. The prognosis is good if pyelonephritis is treated appropriately, but complications include renal abscess, renal impairment, and septic shock.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of: oral antibiotic treatments for acute pyelonephritis in women with uncomplicated infection; antibiotic treatments in women admitted to hospital with complicated infection; inpatient versus outpatient management in women with uncomplicated infection; analgesia in uncomplicated acute pyelonephritis? We searched: Medline, Embase, The Cochrane Library and other important databases up to February 2007 (BMJ Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
Results
We found 5 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
Conclusions
In this systematic review we present information relating to the effectiveness and safety of the following interventions: analgesics, inpatient management, intravenous antibiotics, non-opioids, non-steroidal anti-inflammatory drugs, oral antibiotics, outpatient management, urinary analgesics.
Key Points
Pyelonephritis is usually caused by ascent of bacteria from the bladder, most often Escherichia coli, and is more likely in people with structural or functional urinary tract abnormalities.
The prognosis is good if pyelonephritis is treated appropriately, but complications include renal abscess, renal impairment, and septic shock.
Consensus is that oral antibiotics, given in the outpatient setting, are effective in non-pregnant women with uncomplicated pyelonephritis, although no placebo-controlled studies have been found.
We don't know whether any one treatment regimen is more effective, or what the optimum duration of treatment is, although it may be sensible to continue treatment for at least 10 days.
Broader spectrum antibiotics, such as quinolones, may be more effective compared with narrower spectrum antibiotics, such as ampicillin, amoxicillin, or co-trimoxazole, in areas where resistance to these is common.
In the outpatient setting, we don't know whether intravenous antibiotics are more effective in non-pregnant women with uncomplicated pyelonephritis compared with oral regimens.
Intravenous antibiotics are considered effective in women admitted to hospital with uncomplicated pyelonephritis.
We don't know which is the most effective intravenous antibiotic regimen, or the optimum duration of treatment.
Combining intravenous plus oral antibiotics may be no more effective that oral antibiotics alone, but the evidence is weak.
We don't know whether inpatient treatment improves outcomes compared with outpatient treatment.
We found no evidence that simple analgesics ,NSAIDs, or urinary analgesics reduce pain from uncomplicated pyelonephritis.
NSAIDs may worsen renal function and should be used in caution in women with pyelonephritis.
About this condition
Definition
Acute pyelonephritis, or upper urinary tract infection, is an infection of the kidney characterised by pain when passing urine, fever, chills, flank pain, nausea, and vomiting. White blood cells are almost always present in the urine. White blood cell casts are occasionally seen on urine microscopy. There is no consensus on the definitions for grades of severity. However, in practice, people with acute pyelonephritis may be divided into people who are able to take oral antibiotics, who do not have signs of sepsis, and may be managed at home, and those who require intravenous antibiotics in hospital. Some consider the absolute indications for hospitalisation to be persistent vomiting, progression of uncomplicated urinary tract infection, suspected sepsis, or urinary tract obstruction. Pyelonephritis is considered uncomplicated if caused by a typical pathogen in an immunocompetent person who has normal renal anatomy and renal function. There is little difference in the treatment of men and non-pregnant women. Diagnosis: Women presenting with fever and back pain suggest a possible diagnosis of acute pyelonephritis.Urinalysis and urine culture should be performed to confirm the diagnosis. Pyuria is present in almost all patients and can be detected rapidly with leukocyte esterase test (S: 74% to 95% and E: 94% to 98%) or the nitrite test (S: 92% to 100% and E: 35% to 85%). Bacterial growth of 104-10-5 is 10.000-100.000 colony forming units on urine culture of a mid-stream specimen will confirm bacteriological diagnosis.
Incidence/ Prevalence
The estimated annual incidence per 10,000 people is 27.6 cases in the USA and 35.7 cases in South Korea. Worldwide prevalence and incidence are unknown. The highest incidence of pyelonephritis occurs during the summer months. Women are approximately five times more likely than men to be hospitalised with acute pyelonephritin.
Aetiology/ Risk factors
Pyelonephritis is most commonly caused when bacteria in the bladder ascend the ureters and invade the kidneys. In some cases, this may result in bacteria entering and multiplying in the bloodstream. The most frequently isolated organism is Escherichia coli (56-85%); others include Enterococcus faecalis, Klebsiella pneumoniae, and Proteus mirabilis. In eldery people, E.coli is less common (60%), whereas people who have diabetes mellitus tend to have infections caused by Klebsiella, Enterobacter, Clostridium, or Candida. People with structural or functional urinary tract abnormalities are more prone to pyelonephritis that is refractory to oral therapy or complicated by bacteraemia. Risk factors associated with pyelonephritis in healthy women are sexual intercourse, use of spermicide, urinary tract infection in the previous 12 months, a mother with a history of urinary tract infection, diabetes, and urinary incontinence.The most important risk factor for complicated urinary tract infection is obstruction of the urinary tract. The incidence of drug-resistant microorganisms varies in different geographical areas. Recent hospitalisation, recent use of antibiotics, immunosuppression, recurrent pyelonephritis, and nephrolithiasis increase the risk of drug resistance.
Prognosis
Prognosis is good if uncomplicated pyelonephritis is treated appropriately. Complications include renal abscess, septic shock, and renal impairment, including acute renal failure. Short-term independent risk factors for mortality include age above 65 years, septic shock, being bedridden, and immunosuppression. Conditions such as underlying renal disease, diabetes mellitus, and immunosuppression may worsen prognosis, but we found no good long-term evidence about rates of sepsis or death among people with such conditions.
Aims of intervention
To reduce the duration and severity of symptoms; to prevent or minimise potential complications, with minimum adverse effects.
Outcomes
Urine culture after treatment; signs and symptoms; rates of complications of infection; and adverse effects of treatment.
Methods
BMJ Clinical Evidence search and appraisal February 2007. The following databases were used to identify studies for this systematic review: Medline 1966 to February 2007, Embase 1980 to February 2007, and The Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Clinical Trials 2007, Issue 1. Additional searches were carried out using these websites: NHS Centre for Reviews and Dissemination (CRD) — for Database of Abstracts of Reviews of Effects (DARE) and Health Technology Assessment (HTA), Turning Research into Practice (TRIP), and National Institute for Health and Clinical Excellence (NICE). We also searched for retractions of studies included in the Review. Abstracts of the studies retrieved from the initial search were assessed by an information specialist. Selected studies were then sent to the author for additional assessment, using pre-determined criteria to identify relevant studies. Study design criteria for inclusion in this review were: published systematic reviews and RCTs in any language, at least single blinded, and containing more than 20 individuals of whom more than 80% were followed up. There was no minimum length of follow-up required to include studies. We excluded all studies described as "open", "open label", or not blinded unless blinding was impossible. In addition we use a regular surveillance protocol to capture harms alerts from organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA), which are added to the reviews as required. We excluded studies that were primarily in men, pregnant women, and people with complicated pyelonephritis, or prone to pyelonephritis because of indwelling catheters, or anatomical or functional bladder abnormalities. Most studies examined both men and women, and we have stated how many women were included, when available. We have performed a GRADE evaluation of the quality of evidence for interventions included in this review (see table ).
Table.
Important outcomes | Cure rates, treatment failure, adverse effects | ||||||||
Number of studies (participants) | Outcome | Comparison | Type of evidence | Quality | Consistency | Directness | Effect size | GRADE | Comment |
What are the effects of oral antibiotic treatments for acute pyelonephritis in women with uncomplicated infection? | |||||||||
12 (618) | Cure rates | Oral antibiotics v each other | 4 | –1 | –1 | –1 | 0 | Very low | Quality point deducted for incomplete reporting of results. Consistency point deducted for conflicting results. Directness point deducted for inclusion of men and children |
What are the effects of antibiotic treatments for acute pyelonephritis in women admitted to hospital with uncomplicated infection? | |||||||||
3 (148) | Cure rates | Intravenous antibiotics v each other | 4 | –3 | –1 | –2 | 0 | Very low | Quality points deducted for sparse data, incomplete reporting of results, and insufficient evidence to enable comparisons to be made. Consistency point deducted for different results for different regimens. Directness point deducted for inclusion of small number of different comparators and uncertainty of inclusion of male participants |
2 (203) | Treatment success | Intravenous plus oral v oral antibiotics | 4 | 0 | 0 | –1 | 0 | Moderate | Directness point deducted for small number of comparisons |
3 (385) | Cure rates | Sequential treatment (iv v oral) | 4 | –1 | 0 | –1 | 0 | Low | Quality point deducted for incomplete reporting of results. Directness point deducted for inclusion of different comparator in one study |
1 (54) | Cure rates | Duration of sequential treatment) 11 days v 4 days of antibiotics | 4 | –2 | 0 | –1 | 0 | Very low | Quality points deducted for sparse data and incomplete reporting of results. Directness point deducted for inclusion of male participants |
Type of evidence: 4 = RCT; 2 = Observational; 1 = Non-analytical/expert opinion.Consistency: similarity of results across studies.Directness: generalisability of population or outcomes.Effect size: based on relative risk or odds ratio.
Glossary
- Low-quality evidence
Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
- Moderate-quality evidence
Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
- Very low-quality evidence
Any estimate of effect is very uncertain.
Recurrent cystitis
Disclaimer
The information contained in this publication is intended for medical professionals. Categories presented in Clinical Evidence indicate a judgement about the strength of the evidence available to our contributors prior to publication and the relevant importance of benefit and harms. We rely on our contributors to confirm the accuracy of the information presented and to adhere to describe accepted practices. Readers should be aware that professionals in the field may have different opinions. Because of this and regular advances in medical research we strongly recommend that readers' independently verify specified treatments and drugs including manufacturers' guidance. Also, the categories do not indicate whether a particular treatment is generally appropriate or whether it is suitable for a particular individual. Ultimately it is the readers' responsibility to make their own professional judgements, so to appropriately advise and treat their patients.To the fullest extent permitted by law, BMJ Publishing Group Limited and its editors are not responsible for any losses, injury or damage caused to any person or property (including under contract, by negligence, products liability or otherwise) whether they be direct or indirect, special, incidental or consequential, resulting from the application of the information in this publication.
Contributor Information
Ignacio Neumann, Pontificia Universidad Católica de Chile, , Chile.
M Fernanda Rojas, Pontificia Universidad Católica de Chile, , Chile.
Philippa Moore, Pontificia Universidad Católica de Chile, , Chile.
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