Edit concept Question Editor Create issue ticket


Pyelonephritis is an inflammation of the kidney tissue, calyces, and pelvis.


Pyelonephritis has a very typical presentation which is the classical triad of symptoms. This includes fever, costovertebral angle pain or abdominal pain and nausea or vomiting.

The onset is very rapid and very soon. Very rarely do symptoms take long to develop and maybe present for a few weeks before patient seeks medical care.

Along with the classical triad of symptoms, varying degrees of cystitis will be experienced by the patient. Typical signs of urinary tract infection (UTI) are increased frequency of micturition day and night, dysuria, haematuria, smelly and cloudy urine and lastly, suprapubic pain. These suggest lower urinary tract infection. Loin pain with fever suggest ascent of infection where there is involvement of kidney. So in many cases, the initial symptoms may only be UTI symptoms confined to the lower urinary tract [5].

In small children who cannot complain of dysuria, symptoms are often atypical. The possibility should always be considered in a fretful, febrile sick child who fails to thrive. If there is no underlying urinary tract abnormality it rarely leads to chronic cases in children above 5 years of age.

In elderly patients, apart from typical symptoms delirium may be present.

Chronic pyelonephritis usually presents with continuous abdominal pain along with persistent fever. Along with that anorexia, loss of weight, malaise and fever, chills will be present. Many cases of pyelonephritis may only present with pyrexia of apparently unknown origin. Haematuria and proteinuria is also common in chronic cases. Blood urea nitrogen is raised in most cases.

Complicated cases of pyelonephritis arise when there are structural or functional abnormalities with the urinary system. Frequent urinary instrumentation can also lead to this condition [6].

Severe complicated cases can lead to septicaemia, hypotension and shock if left untreated.

  • After a transient initial improvement, his dyspnea worsened, fever recurred and he developed a tender submandibular abscess.[ncbi.nlm.nih.gov]
  • It is characterized by abdominal pain; fever; nausea; vomiting; and occasionally diarrhea[icd9data.com]
  • Chronic pyelonephritis usually presents with continuous abdominal pain along with persistent fever. Along with that anorexia, loss of weight, malaise and fever, chills will be present.[symptoma.com]
  • In babies, the most common signs include fever, irritability, vomiting and diarrhea, poor feeding, and failure to gain weight, but most babies will just have a high fever without any other symptoms.[urology.ucsf.edu]
  • A multivariate analysis with the age, chills, platelet count and urine nitrite test results revealed that older age, positive urinary nitrite test results and chills tended to be associated with bacteremia, respectively.[ncbi.nlm.nih.gov]
  • Signs and symptoms include fever, chills, flank pain, painful and frequent urination, cloudy or bloody urine, and confusion Inflammation of the kidney and its pelvis due to infection Inflammation of the kidney involving the renal parenchyma (the nephrons[icd9data.com]
  • ‘High fever with chills is typical of pyelonephritis and pneumonia.’ ‘Parenteral treatment of pyelonephritis should be continued until the patient becomes afebrile.’[en.oxforddictionaries.com]
  • High fever and shaking chills also may be signs that your kidney infection has spread to your bloodstream and can travel to others parts of your body.[drugs.com]
  • The symptoms of pyelonephritis include: A high fever and/or chills Nausea Vomiting Confusion Pain in the back and/or sides Fatigue People with diabetes or conditions that diminish their immune system are more at risk for pyelonephritis, but just about[tgh.org]
  • Review of systems was significant for unintentional weight loss of 14 pounds over the last two to three months with malaise and fatigue, in the absence of fever and chills.[appliedradiology.com]
  • Some patients have fever, flank or abdominal pain, malaise, or anorexia. In XPN, a unilateral mass can usually be palpated.[merckmanuals.com]
  • Other features of lower UTI may be present e.g. frequency, dysuria etc Fever can often be high enough to cause rigors Other systemic features may also be present e.g. nausea/vomiting, anorexia, malaise and occasionally diarrhoea Investigations Urinalysis[dundeemedstudentnotes.wordpress.com]
  • Signs and Symptomology Acute pyelonephritis is a deep infection and patients often display consitutional symptoms such as fever, chills, and malaise.[pathwaymedicine.org]
  • The symptoms of pyelonephritis include: A high fever and/or chills Nausea Vomiting Confusion Pain in the back and/or sides Fatigue People with diabetes or conditions that diminish their immune system are more at risk for pyelonephritis, but just about[tgh.org]
  • Fatigue: You may feel fatigued or low energy as a result of your body fighting off an infection. Back pain: Back pain, or flank pain, can result from a kidney infection and is experienced close to where the kidneys are located.[belmarrahealth.com]
  • Rest is indicated to reduce fatigue, increase comfort, and allow the body to combat the infection.[medical-dictionary.thefreedictionary.com]
Flank Mass
  • Most patients presented with anemia, chronic febrile illness, a painful tender flank mass and recurrent urosepsis. Some features of nephrogenic hepatic dysfunction were present in 13 patients.[ncbi.nlm.nih.gov]
  • It is characterized by abdominal pain; fever; nausea; vomiting; and occasionally diarrhea[icd9data.com]
  • 7.02 Upper Urinary Tract Infection (Pyelonephritis) Presentation The patient has some combination of urinary frequency, urgency, dysuria, flank pain, nausea, fever, and chills.[ncemi.org]
  • ) 93 (90–100) 94 (91–100) Rash, urticaria,nausea, vomiting, hematologic [ 36 , 37 ] Fosfomycin trometamol (3 g single-dose sachet) 91 80 (78–83) Diarrhea, nausea,headache [ 39 , 40 ] Pivmecillinam (400 mg twice daily for 3–7 days) 73 (55–82) 79 (74–84[doi.org]
  • Nausea, vomiting,lightheadedness, confusion or loss of consciousness due to sepsis and shock (this can occur if bacteria enter the bloodstream from the kidney) in the most severe form of pyelonephritis.[longdom.org]
  • In addition to antibiotics, a person with pyelonephritis can also receive analgesics (think opioids) for pain and promethazine for nausea and vomiting. Treatment of uncomplicated pyelonephritis lasts about seven days.[verywellhealth.com]
Abdominal Pain
  • Here, we describe a 12-year-old boy who presented with abdominal pain. He did not have any history of urinary tract infection. Computed tomography and magnetic resonance imaging showed a cystic lesion in the left upper kidney.[ncbi.nlm.nih.gov]
  • It is characterized by abdominal pain; fever; nausea; vomiting; and occasionally diarrhea[icd9data.com]
Suprapubic Pain
  • pain is also often present.[dundeemedstudentnotes.wordpress.com]
  • Typical signs of urinary tract infection (UTI) are increased frequency of micturition day and night, dysuria, haematuria, smelly and cloudy urine and lastly, suprapubic pain. These suggest lower urinary tract infection.[symptoma.com]
  • There is unilateral or bilateral loin pain, suprapubic pain or back pain. Fever is variable but can be high enough to produce rigors. Malaise, nausea, vomiting, anorexia and occasionally diarrhoea occur.[patient.info]
  • pain, or urgency) together with the presence of pyuria (a positive leukocyte esterase dipstick test result, subsequently confirmed by urinalysis with more than ten leukocytes/mL in urine without centrifuging or more than five leukocytes per high-power[indianjnephrol.org]
  • Diverticulitis : Due to bowel innervation, this condition can present with flank pain or suprapubic pain, although it most commonly presents with left lower quadrant pain.[emdocs.net]
Lower Abdominal Pain
  • She was admitted to our hospital with fever, urodynia, lower abdominal pain, gross hematuria, and cloudy urine. Urine cultures were positive for S. Schwarzengrund. Exposure to cats, especially stray cats, were identified as the most likely source.[ncbi.nlm.nih.gov]
  • In older children, common signs include burning or pain with urination, frequent or urgent urination, fever, lower abdominal pain, new or more frequent incontinence, side or back pain, or blood in the urine.[urology.ucsf.edu]
Poor Feeding in Infants
  • Acute pyelonephritis causes high fever, vomiting, stomach pain, irritability and poor feeding in infants. We wanted to find out if oral antibiotics were as effective as combined oral and injected antibiotics to treat children for kidney infection.[doi.org]
Back Pain
  • However, children are usually sicker with fever, back pain, or vomiting with pyelonephritis. Keep in Mind Pyelonephritis requires medical attention.[kidshealth.org]
  • pain and vomiting may also be present if the infection has moved to the kidneys.[bladderbowel.gov.au]
  • In this case, the diagnosis was delayed because the state of quadriplegia rendered no symptoms of XGP.[ncbi.nlm.nih.gov]
Flank Pain
  • A 41-year-old woman with recurrent urinary tract infections presented with right flank pain, fever, and anorexia. Physical examination revealed right-sided flank pain and a right-sided unilateral renal mass.[ncbi.nlm.nih.gov]
  • Signs and symptoms include fever, chills, flank pain, painful and frequent urination, cloudy or bloody urine, and confusion Inflammation of the kidney and its pelvis due to infection Inflammation of the kidney involving the renal parenchyma (the nephrons[icd9data.com]
  • Other diagnostic findings are leukocytosis, CVAT or flank pain, and WBC casts in the urine. See also Urinary Tract Infection, which has many related diagnostic findings, including CVAT and flank pain.[getthediagnosis.org]
  • Dysuria : Dysuria – also known as painful urination – is a condition that can be an early sign of a urinary tract infection. Dysuria leads to feeling pain, discomfort, or burning while urinating.[belmarrahealth.com]
  • Patient also reported history of renal stones, but denied any dysuria or hematuria.[appliedradiology.com]
  • The authors found dysuria to have a likelihood ratio (LR) of 1.3, frequency to have a LR of 1.10, hematuria a LR of 1.72, nocturia a LR of 1.30, and urgency a LR of 1.22.[emdocs.net]
  • He presented with symptoms of lumbar pain and dysuria. Chest radiograph demonstrated mediastinal lymphadenopathy and a CECT of the head showed a tuberculous granuloma.[ncbi.nlm.nih.gov]
  • ., dysuria, frequency). Urinalysis reveals leukocyturia and bacteriuria. Urine cultures should be taken in all patients before initiating treatment to identify the pathogen and possible antibiotic resistance.[amboss.com]
  • The urine microscopic examination may show hematuria, but hematuria is nonspecific. White cell casts are suggestive of pyelonephritis. Proteinuria is expected up to 2 grams/day.[cancertherapyadvisor.com]
  • All patients were symptomatic, and the most common symptoms were fever, flank or abdominal pain, weight loss, lower urinary tract symptoms, and gross hematuria.[ncbi.nlm.nih.gov]
  • ‘Because of hematuria, bacteriuria and pyuria, Susan had been treated for a urinary tract infection with possible pyelonephritis.’ ‘High fever with chills is typical of pyelonephritis and pneumonia.’[en.oxforddictionaries.com]
Kidney Failure
  • The brief claim that pyelonephritis may be the leading cause of kidney failure in the early 1960s was put to rest with the advent of nephrology as an investigative scientific discipline.[jasn.asnjournals.org]
  • This carries the risk that the infectious inflammatory disease may progress slowly undetected over many years until there is enough deterioration to produce kidney failure.[healthcentral.com]
  • These anatomical anomalies can cause frequent urinary tract infections during adolescence, which may eventually result in kidney damage and eventual kidney failure, warranting a transplant.[tgh.org]
  • If you have kidney failure, you should not drink this much liquid. Talk with your health care professional about how much liquid is right for you.[niddk.nih.gov]
  • But it has come to be a 'fallback diagnosis', i.e. when doctors are not sure of the cause of kidney failure, and the kidney has scars on its surface, they call it CP.[kidneycareuk.org]


Diagnosis can be done on three parameters mainly history taking, physical examination and lastly, laboratory tests. A complete history regarding the onset, duration and severity of symptoms should be taken.

Patient may be febrile [7] and other vital parameters maybe affected. Tachycardia and hypotension may occur in severe cases. Patient may appear dehydrated and uncomfortable.

Abdominal examination will show costovertebral angle tenderness which can be either unilateral or bilateral. Lumbar tenderness and abdominal guarding is mostly always present. Suprapubic tenderness will be usually present. In women, pelvic examination has to be done to rule out any other pathology.

Laboratory tests in the form of urine analysis [8], microscopy, and culture should be done. Urine reports will always show signs of infection mainly presence of bacteria and increase white blood cells. Pus cells may be there. Culture and sensitivity is done for correct diagnosis and treatment [9]. Blood urea nitrogen, creatinine, and urea levels tend to be elevated.

Imaging techniques done are plain radiographs which help to detect stones. Ultrasound may be used to detect tumours, blockages and abscesses. In addition, CT scan maybe taken for complete detailed images of kidney and urinary tract and their surrounding tissues.

  • Urographically, a renal mass lesion was encountered in 62% of the patients, nephrolithiasis in 38% and a functionless kidney in 27%. Angiographically, none of the 4 mass lesions studied was distinguished from hypernephroma.[ncbi.nlm.nih.gov]
  • Urographically, a renal mass lesion was encountered in 62 per cent of the patients, nephrolithiasis in 38 per cent and a functionless kidney in 27 per cent. Angiographically, none of the 4 mass lesions studied was distinguished from hypernephroma.[doi.org]
  • ., benign prostatic hyperplasia, vesicoureteral reflux, nephrolithiasis, ureteral strictures) Cystitis Recent administration of antibiotics (possible antibiotic resistance) Immunosuppression (e.g., HIV, diabetes ) Acute kidney injury References: [1] [[amboss.com]
  • "Chapter 22: Pyelonephritis and other infections, reflux nephropathy, hydronephrosis, and nephrolithiasis". In Jennette, JC; Olson, JL; Schwartz, MM; et al. (eds.). Heptinstall's Pathology of the Kidney. 2 (6th ed.).[en.wikipedia.org]
  • We believe that cases with free intraperitoneal air should promptly undergo laparotomy to identify the cause of the pneumoperitoneum.[ncbi.nlm.nih.gov]
  • She was admitted to our hospital due to fever and unconsciousness with pyuria. The abdominal computed tomography showed left pneumatosis and urinary stone.[ncbi.nlm.nih.gov]
  • Pyuria, which is defined as more than 5-10 white blood cells (WBCs) per high-power field, is present in almost all patients with pyelonephritis.[cancertherapyadvisor.com]
  • ‘Because of hematuria, bacteriuria and pyuria, Susan had been treated for a urinary tract infection with possible pyelonephritis.’ ‘High fever with chills is typical of pyelonephritis and pneumonia.’[en.oxforddictionaries.com]
  • ., frequency, urgency ) Weakness, nausea, vomiting ( diarrhea may also be present) Possible abdominal or pelvic pain References: [3] Diagnostics Laboratory tests Urinalysis Pyuria ( positive esterase on dipstick test ), leukocyturia, WBC casts Bacteriu[amboss.com]
  • Infants may develop hyperkalemia and hyponatremia. Montini G, Tullus K, Hewitt I. Febrile urinary tract infections in children. N Engl J Med. 2011 Jul 21. 365(3):239-50. [Medline]. Morello W, La Scola C, Alberici I, Montini G.[emedicine.com]


The treatment depends on the severity of symptoms. The mainstay of treatment is antibiotics. Hospitalization is often required as the infection gets diagnosed late.

Antibiotics are given for a minimum of 7 days. Intravenous administration may be given initially to start the treatment. This ensures that the medication reaches the kidney. A high daily fluid intake (2 litres) is advised. After 5 days of treatment urine analysis studies should be repeated [10].

If the patient is severely ill, hospitalization is needed with intravenous administration of medication, switching to a further 7 day oral therapy as symptoms improve. Intravenous fluids may be required for a good urine output.

In patients presenting for the first time with high fever and loin pain suddenly, an urgent renal ultrasound should be done to exclude abscess formation. Most cases of pyonephrosis require drainage by a percutaneous nephrostomy.

Pre-treatment and post-treatment urine culture is mandatory to confirm the diagnosis and identify whether recurrent infection is a relapse or reinfection.


A single episode of acute pyelonephritis will rarely cause any renal scarring or damage. Recovery rate is very good with appropriate antibiotic therapy. The key to full recovery is early diagnosis and prompt treatment. Recovery in acute cases is within days to weeks.

Repeated attacks can lead to chronic pyelonephritis, which can result in various complications. In complicated cases, recovery rates depend on patient’s age and whether any other renal pathology is involved.

It is important to take the complete course of antibiotics. Long term monitoring is required for recurrent cases. Prophylactic treatment can be given.


Bacteria commonly found in stool are the main etiological agents from this infection. Most commonly responsible bacteria are Escherichia coli, Proteus, Klebsiella and Pseudomonas. E. coli is found in 85% of cases. Gram-positive agents like Enterococcus Faecalis and Staphylococcus Aureus can also cause pyelonephritis.
Most of the cases of pyelonephritis start with cystitis and prostatitis [2].

A number of other risk factors are also associated which increase and maintain the infection; mainly individuals with structural abnormalities in the urinary tract and vesicoureteral reflux. Mechanical obstructions in the form of kidney stones, benign tumours or frequent catheterization are also important risk factors.

Sexual activity with different partners can also predispose to frequent urinary infections.

Systemic diseases like diabetes mellitus or immunocompromised individuals have higher chances of developing pyelonephritis.


Uncomplicated cases of pyelonephritis mainly affect women more than men. These are usually acute episodes. The incidence is about 12-13 cases per 10000 in women and 2-3 cases per 10000 in men. Women are affected more due to a shorter length of urethra and the infection occurs in sexually active women more frequently [3].

Pyelonephritis with complications occurs more in elderly men. Since the presentation of symptoms is atypical in infants and children, it is difficult to demonstrate such cases. Though it’s more common in men than women, the difference reduces as age progresses, especially after 65 years, when it is equal.

Sex distribution
Age distribution


Infection in most of the cases is due to bacteria from the patient’s own bowel flora, E. coli being the commonest causative agent.
Transfer to the urinary tract maybe via the bloodstream, the lymphatics or through the transurethral route. Transurethral route is the most common mode of transport for these bacteria. Three important steps play a role in the pathogenesis:

  • Periurethral colonization with bacteria which is facilitated by adhesion of bacteria to uroepithelial surfaces by pili or fimbriae present on the bacteria. Other factors which maintain this vicious circle are a lack of personal hygiene. Local infections have been incriminated too.
  • Transurethral passage of microoraganisms along the urethra to the bladder. Sexual intercourse and catherisation facilitate this transport. This occurs easily in females due to shorter length of urethra compared to males [4].
  • Establishment of bacteria in the bladder which is the most important aspect of this pathogenesis. As a result, the bacteria grow and multiply. Normally, urine in bladder is sterile due to bladder defence mechanisms.

This extension of infection is made easy by vesicoureteric reflux and dilated hypotonic ureters. Once infection is established, it can easily pass up or down the system.


Recurrent UTI infections should be prevented by improving fluid intake, improving micturating habits, and personal hygiene after sexual intercourse. Witholding of urine can lead the infection to grow. Women should void urine immediately after sexual intercourse to prevent ascent of bacteria. After micturition women should wipe from back to front. Avoidance of constipation may improve bladder emptying.

Recurrent UTI’s should be thoroughly investigated for any underlying pathology. Long term low dosage prophylaxis can be given for a period of 6 – 12 months in patients with repeated UTI’s with nitrofurantoin.


Pyelonephritis is an infection of the kidney which results in an inflammation of the renal parenchyma, calyces and renal pelvis. Pyelonephritis is mainly a result of a urinary tract infection.
Most of the urinary infections involve only urethra and urinary bladder but when it progresses up to involve the kidney and ureters, pyelonephritis occurs. Pyelonephritis is a result of urinary tract infections wherein an acute episode of fever, nauseavomiting and abdominal pain radiating to the back may present suddenly [1].

If left untreated it can lead to severe sepsis, shock, delirium and ultimately multi organ failure. Recurrent infections cause considerable mortality and morbidity. In complicated cases, it can lead to severe renal disease which can lead to renal failure. It can also lead to permanent renal scaring. It’s a common source of life threatening Gram-negative septicaemia.

Chronic pyelonephritis usually results from recurrent renal infections, vesicouretral reflux and other structural abnormalities in urinary tract. This usually happens in elderly or infants. Complications always arise with chronic pyelonephritis.
In men, benign prostatic hyperplasia is an important predisposing factor.

Pyelonephritis needs to be treated immediately with antibiotic therapy to prevent life threatening complications. Recurrence and reinfection can occur.

Patient Information

Pyelonephritis is an infection of the kidney which is caused by bacteria that reach the kidneys from the urinary bladder. Pyelonephritis is mostly a result of a urinary tract infection.

Women are at a higher risk of getting pyelonephritis due to easier access for bacteria to enter primarily due to shorter length of urethra. This condition is more common in sexually active women.
The most common cause is a bacteria which is normally present in the faeces. This bacteria E. coli travels upwards towards the urinary tract and causes infection which ultimately reaches the kidneys. This results in a severe infection which can travel any way through the urinary system.

The main symptoms include fever and pain in the back which may radiate till the abdomen. Difficulty in passing urine, frequent urination along with foul smelling cloudy urine may also be present. In severe complications, the infection may spread to the whole body which can result in multiorgan failure.

Early diagnosis should be done for complete recovery. If any of the above symptoms are present immediate medical help should be sought. A medical care provider will be able to diagnose the case with a simple case taking and clinical examination. Laboratory tests in the form of urine tests will be done along with imaging techniques to detect the severity. CT scans may be done for complete study of kidneys.

Treatment is with immediate antibiotic therapy along with increased fluid intake. Complete course of antibiotic should be taken for complete recovery. Urine should be tested post treatment to prevent any reinfection or relapse.

In all cases there is complete recovery unless there is some complication mainly any abnormality in the urinary tract and system. Chronic cases tend to reoccur for which preventive therapy is given.

At least 6-8 glasses of water should be taken daily. Women should urinate before bed time and after sexual activity. Personal hygiene should be maintained after urination.

Early detection and immediate treatment is the most important aspect in controlling the infection and preventing a relapse or reinfection.



  1. Stamm WE. Urinary tract infections and pyelonephritis. In: Harrison TR, Braunwald E, Eds. Harrison’s Principles of internal medicine. 15th ed. New York: McGraw-Hill, 2001:1620–6.
  2. Gupta K, Hooton TM, Wobbe CL, Stamm WE. The prevalence of antimicrobial resistance among uropathogens causing acute uncomplicated cystitis in young women. Int J Antimicrob Agents. 1999 May;11(3-4):305–8.
  3. Foxman B, K. L. Klemstine, and P. D. Brown. Acute Pyelonephritis in Us Hospitals in 1997: Hospitalization and in-Hospital Mortality. Ann Epidemio. 2003; 13(2): 144-150.
  4. Gilstrap LC, Ramin SM. Urinary tract infections during pregnancy. Obstet Gynecol Clin North Am. 2001 Sep;28(3):581–91.
  5. Colgan, William R, and J. R. Johnson. Diagnosis and Treatment of Acute Pyelonephritis in Women. Am Fam Phys. 2011 Sep 1; 84(5): 519-526.
  6. Tambyah PA, Maki DG. Catheter-associated urinary tract infection is rarely symptomatic: a prospective study of 1,497 catheterized patients. Arch Intern Med. 2000 Mar 13;160(5):678–82.
  7. Pinson AG, Philbrick JT, Lindbeck GH, Schorling JB. Fever in the clinical diagnosis of acute pyelonephritis. Am J Emerg Med. 1997 Mar;15(2):148–51.
  8. Pollock HM. Laboratory techniques for detection of urinary tract infection and assessment of value. Am J Med. 1983 Jul 28;75(1B):79–84.
  9. Ferry S, Andersson SO, Burman LG, Westman G. Optimized urinary microscopy for assessment of bacteriuria in primary care. J Fam Pract. 1990 Aug 3;31(2):153–9. discussion 159-61.
  10. Rubin RH, Shapiro ED, Andriole VT, Davis RJ, Stamm WE. Evaluation of new anti-infective drugs for the treatment of urinary tract infection. Infectious Diseases Society of America and the Food and Drug Administration. Clin Infect Dis. 1992 Nov;15(suppl 1):S216–27

Ask Question

5000 Characters left Format the text using: # Heading, **bold**, _italic_. HTML code is not allowed.
By publishing this question you agree to the TOS and Privacy policy.
• Use a precise title for your question.
• Ask a specific question and provide age, sex, symptoms, type and duration of treatment.
• Respect your own and other people's privacy, never post full names or contact information.
• Inappropriate questions will be deleted.
• In urgent cases contact a physician, visit a hospital or call an emergency service!
Last updated: 2019-07-11 22:01