Home :: Pyelonephritis

Pyelonephritis - Acute And Chronic

Alternative names :- Urinary tract infection - complicated; Infection - kidney; Complicated urinary tract infection

Acute pyelonephritis, also known as acute infective tubulointerstitial nephritis, is a sudden inflammation caused by bacteria that primarily affects the interstitial area and the renal pelvis or, less commonly, the renal tubules. It's one of the most common renal diseases. With treatment and continued follow-up care, prognosis is good and extensive permanent damage is rare. It's more common in females than in males. It can also cause pregnant women to have premature labor.

Causes of Pyelonephritis

Typically, the infection spreads from the bladder to the ureters, then to the kidneys, as in vesicoureteral reflux. Vesicoureteral reflux may result from congenital weakness at the junction of the ureter and the bladder. Bacteria refluxed to intrarenal tissues may create colonies of infection within 24 to 48 hours. Infection may also result from instrumentation (such as catheterization, cystoscopy, or urologic surgery), hematogenic infection (as in septicemia or endocarditis) or, possibly,lymphatic infection.

Pyelonephritis may also result from an inability to empty the bladder (for example, in patients with neurogenic bladder), urinary stasis, or urinary obstruction due to tumors, strictures, or benign prostatic hyperplasia.

Pyelonephritis occurs more commonly in females, probably because of a shorter urethra and the proximity of the urinary meatus to the vagina and the rectum, which allow bacteria to reach the bladder more easily, and a lack of the antibacterial rostatic secretions produced in the male. Incidence increases with age and is higher in the following groups:

• sexually active women. Intercourse increases the risk of bacterial contamination.
• pregnant women. About 5% develop asymptomatic bacteriuria; if untreated, about 40% develop pyelonephritis.
• diabetics. Neurogenic bladder causes incomplete emptying and urinary stasis; glycosuria may support bacterial growth in the urine.
• persons with other renal diseases. Compromised renal function aggravates susceptibility.

Signs and symptoms of Pyelonephritis

Typical clinical features include urgency, frequency, burning during urination, dysuria, nocturia, and hematuria (usually microscopic but may be gross). Urine may appear cloudy and have an ammonia-like or fishy odor. Other common symptoms include a temperature of 102°F (38.9°C) or higher, shaking chills, flank pain, anorexia, and general fatigue.

These symptoms characteristically develop rapidly over a few hours or a few days. Although these symptoms may disappear within days, even without treatment, residual bacterial infection is likely and may cause symptoms to recur later.

Diagnosis of Pyelonephritis includes:

Diagnosis requires urinalysis and culture. Typical findings include:

• pyuria (pus in urine). Urine sediment reveals the presence of leukocytes singly, in clumps, and in casts and, possibly, a few red blood cells.
• significant bacteriuria. Urine culture reveals more than 100,000 organisms/mm3 of urine.
• low-specific gravity and osmolality. These findings result from a temporarily decreased ability to concentrate urine.
• slightly alkaline urine pH. Alkaline urine pH results from the production of urease from the bacteria or organism, which breaks down the urea.
• proteinuria, glycosuria, and ketonuria. These findings usually occur in patients with diabetes who are at increased risk for infections including pyelonephritis.

Computed tomography scan also helps in the evaluation of acute pyelonephritis. CT scan of the kidneys, ureters, and bladder may reveal calculi, tumors, or cysts in the kidneys and the urinary tract. Excretory urography may show asymmetrical kidneys.

Pyelonephritis treatment

Treatment focuses on antibiotic therapy appropriate to the speci1ic infecting organism after identification by urine culture and sensitivity studies. For example, Enterococcus requires treatment with ampidllin, penidllin G, or vancomycin. Staphylococcus requires penidllin G or, if resistance develops, semisynthetic penidllin, such as nafdllin, or a ephalosporin. E. colimay be treated with sulfisoxazole, nalidixic add, and nitrofurantoin. Proteus may be treated with ampicillin, sulfisoxazole, nalidixic add, and a cephalosporin. Pseudomonas requires gentamicin, tobramycin, or carbenidllin. When the infecting or ganism can't be identified, therapy usually consists of a broad-spectrum antibiotic, such as ampidllin or cephalexin. If the patient is pregnant, antibiotics must be prescribed cautiously. Urinary analgesics such as phenazopyridine are also appropriate.

Symptoms may disappear after several days of antibiotic therapy. Although urine usually becomes sterile within 48 to 72 hours, the full course of such therapy is 10 to 14 days. Follow-up treatment includes reculturing urine 1 week after drug therapy stops and then periodically for the next year to detect residual or recurring infection. Most patients with uncomplicated infections respond well to therapy and don't suffer reinfection.

If infection results from obstruction or vesicoureteral reflux, antibiotics may be less effective; treatment may then necessitate surgery to relieve the obstruction or correct the anomaly. Patients at high risk for recurring urinary tract and kidney infections, such as those with prolonged use of an indwelling catheter or maintenance antibiotic therapy, require long-term follow-up. Recurrent episodes of acute pyelonephritis can eventually result in chronic pyelonephritis

Complications

• Recurrence of pyelonephritis
• Perinephric abscess (infection around the kidney)
• Sepsis
• Acute renal failure

Special considerations and Prevention

Patient care is supportive during antibiotic treatment of underlying infection:

• Administer antipyretics for fever.
• Force fluids to achieve urine output of more than 2,000 ml/day to help empty the bladder of contaminated urine. Don't encourage intake of more than 2 to 3 qt (2 to 3 L) because this may decrease the effectiveness of the antibiotics.
• Provide an acid-ash diet to prevent stone formation.
• Teach proper technique for collecting a clean-catch urine specimen. Be sure to refrigerate or culture a urine specimen within 30 minutes of collection to prevent overgrowth of bacteria.
• Prompt and complete treatment of cystitis (bladder infection) may prevent development of many cases of pyelonephritis. Chronic or recurrent urinary tract infection should be treated thoroughly because of the chance of infection of the kidneys.
• Stress the need to complete prescribed antibiotic therapy. even after symptoms subside. Encourage long term follow-up care for high-risk patients.
• Increasing the intake of fluids (64 to 128 ounces per day) encourages frequent urination that flushes bacteria from the bladder. Drinking cranberry juice prevents certain types of bacteria from attaching to the wall of the bladder and may lessen the chance of infection.

back to gynaecological problems section