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Acute Cystitis

Acute Cystitis

Article Author:
Vasimahmed Lala
Article Editor:
David Minter
11/20/2020 4:17:44 PM
For CME on this topic:
Acute Cystitis CME
PubMed Link:
Acute Cystitis


A urinary tract infection (UTI) is defined as significant bacteriuria in the setting of symptoms of cystitis or pyelonephritis. It is pathogenic inflammation of the upper or lower urinary tract. Women are more commonly afflicted with UTIs and caused by common pathogens such as Escherichia coli (86%) and Staphylococcus saprophyticus (4%). Many women know the symptoms of cystitis which include frequent trips to the bathroom and a stinging and burning sensation when passing urine. A diagnosis of uncomplicated cystitis may be made by history findings, on physical examination, as well as with urinalysis (UA). The severity of the disease can range widely and can result in hospital admission or outpatient treatment.[1][2][3][4]


Most UTIs in females are acute uncomplicated cystitis caused by Escherichia coli (86%), Staphylococcus saprophyticus (4%), Klebsiella species (3%), Proteus species (3%), Enterobacter species (1.4%), Citrobacter species (0.8%), or Enterococcus species (0.5%). Urethral catheterization accounts for 80% of nosocomial UTIs; 5% to 10% are related to genitourinary manipulation. Sexual intercourse results in an increased risk, as does use of a diaphragm or spermicide.[5][6]


Urinary tract infections (UTI) are the most common bacterial infection in women. About 40% of women experiencing a UTI at some point in their lives. The abundance of this disease results in eight million emergency or clinic visits, 100,000 hospital admissions, and annually, $1.6 billion in healthcare costs. Within a year of infection, 27% to 46% of women will have another UTI.


Bacterial invasion of the urothelium of the bladder from bacteria migrating from the rectum as well as colonized bacteria from the perineum and vagina. Age is an important factor as estrogen diminishes with age, and pH increases, thus promoting colonization of with gram-negative enteric organisms such as E. coli.

History and Physical

A history is the most important tool for diagnosis of acute uncomplicated cystitis, and it should be supported by a focused examination and urinalysis. It also is important to rule out a more serious, complicated UTI. The new onset of frequency and dysuria, with the absence of vaginal discharge, has a positive predictive value of 90% of UTI.[7][8][9][10]


  • Cystitis: Frequency, dysuria, urgency, suprapubic pain, cloudy urine, hematuria, nausea, vomiting, and fever
  • Pyelonephritis: Similar symptoms of cystitis but usually will have flank pain, fever, and other systemic symptoms
  • Elderly: Apart from a typical presentation they tend to have altered mental status, lethargy, and generalized weakness.

Cystis can be either complicated or uncomplicated, and the workup, as well as treatment, is guided by identifying which category the patient falls into.

Uncomplicated:  Absence of anatomic or functional abnormalities

Complicated: Anatomical or systemic factors that increase the chance of infection like male gender, diabetes, immunosuppression, polycystic kidney, hospital-acquired, bladder outflow obstruction (prostate hypertrophy, urethral stricture), neuropathic bladder (multiple sclerosis, diabetes mellitus), catheterization or ureter stent, ureterolithiasis, genitourinary surgery or malignancy, vesicoureteral reflux

Physical Exam

A physical examination with acute uncomplicated cystitis is typically normal except in 10% to 20% of women with suprapubic tenderness. Acute pyelonephritis may be suspected if the patient is ill-appearing and seems uncomfortable, particularly if she has a concomitant fever, tachycardia, or costovertebral angle tenderness.

Self Diagnosis and Diagnosis by Telephone

Two recent studies suggest that women who self-diagnose a UTI may be treated safely via telephone management. Women who are treated with acute uncomplicated cystitis previously are usually accurate in determining when they are having another episode.


The convenience and cost-effectiveness of a urine dipstick test make it a common diagnostic tool. It is an appropriate alternative to urinalysis and urine microscopy in the diagnoses acute uncomplicated cystitis. Nitrite and leukocyte esterase are the most accurate indicators of acute uncomplicated cystitis in symptomatic women. 

Urinalysis with microscopy: Ideally mid-steam catch or catheter oriented to avoid contamination. However, at least two studies have shown no significant difference in contaminated or unreliable results in specimens collected either with and without preliminary cleansing.

Nitrites: Bacteria reduction of nitrate to nitrite; typically by gram-negative organisms. Under normal circumstance, urine will have no nitrites. False positives can result from air exposure, and false negative can be the result of the non-nitrite producing organism,  low nitrate diet (decreased vegetables), vitamin C, concentrated urine and low pH.

  • Sensitivity (19% to 48%) and specificity (92% to 100%)

Leukocyte Esterase: Presence of intact or broken down neutrophils. False negatives can be the result of an early infection, vitamin C, concentrated urine, ketonuria, and proteinuria. False positives can be caused by contamination of the urine by skin flora

  • Sensitivity (62% to 98%) and  specificity (55% to 96%)

Pyuria: more than five white blood cell count (WBC) per HPF = Sensitivity (90% to 96%) and specificity (47% to 50%)

WBC Casts: coagulum of Tamm Horsfall mucoprotein and leukocytes from renal tubular lumen which can indicate pyelonephritis

  • Other causes: glomerulonephritis, interstitial nephritis

Bacteria: For clean-catch urine should have colony count more than 100,000 CFU/mL for a single organism. 20% to 40% of women presenting with cystitis have 100-10,000 CFU/mL

Urine culture: Not needed in simple cystitis. Indication for culture is complicated infections, pyelonephritis, and prior antimicrobial treatment. Routine posttreatment urinalysis or urine cultures in asymptomatic patients are not necessary

Imaging: Not needed in routine cases. Ultrasound can evaluate for hydronephrosis or abscess. CT can help you evaluate for kidney stones, hydronephrosis, emphysematous changes, and abscess.


Treatment / Management

There are many things to consider when treating cystitis. The choice between agents should be individualized and depends on the duration of treatment as well as the possible organism involved. According to guidelines, there is no single, best agent to treat acute uncomplicated cystitis. Choosing an antibiotic depends on its effectiveness, the risk of adverse effects, resistance rates, and propensity to cause collateral damage; furthermore, physicians should consider cost, availability, and patient factors, such as allergy history. On average, patients will experience symptom relief within 36 hours of the beginning treatment. 

Uncomplicated Cystitis

  • Nitrofurantoin (Macrobid) 100 mg by mouth twice a day for 5 days
  • Trimethoprim-sulfamethoxazole 160 mg/800 mg twice a day for 3 days
  • Ciprofloxacin 250 mg twice a day or levofloxacin 250 mg twice a day for 3 days
  • Alternatives are B-lactams such as amoxicillin-clavulanate 500/125 mg twice a day for seven days or Cephalexin 250 mg four times per day for 3 to 7 days.

Complicated Cystitis

There is no absolute guideline for treatment typically requires a longer duration (about seven days). Recommended treatments are listed below.

Nonpregnant women

  • Ciprofloxacin 500 mg by mouth twice a day 7 to 10 days
  • Nitrofurantoin Monohydrate/microcrystals 100 mg mouth twice a day for 7 days

Pregnant women

A shorter course of antibiotic therapy is preferred in pregnant patients. Fluoroquinolones are contraindicated during pregnancy. Nitrofurantoin is contraindicated in a pregnant patient at term, during labor, and delivery. 

  • Amoxicillin-clavulanate 500 mg/12 mg by mouth twice a day for 7 days 
  • Keflex 500 mg by mouth four times a day for 3 to 5 days
  • Cefpodoxime 100 mg twice a day for 5 to 7 days.


Acute cystitis is always recognized as complicated. Men with cystitis who do not have signs or symptoms of prostatitis can be treated with the following regiments.

  • Ciprofloxacin 500 mg by mouth twice a day for 7 days
  • Levofloxacin 750 mg by mouth four times a day for 7 days
  • Macrobid 100 mg by mouth twice a day for 7 days.

Differential Diagnosis

  • Cervicitis
  • Epididymitis
  • Prostatitis
  • Syphilis
  • Urethritis
  • Vulvovaginitis

Pearls and Other Issues

Antibiotic Resistance

First-line therapy for acute uncomplicated cystitis should not include beta-lactam antibiotics. This is because widespread E. Coli resistance rates are above 20%. Fluoroquinolone resistance is below 10% in North America and Europe. Treatment should be individualized based on local resistance.

Possible indications for Admission

  • Failed outpatient treatment
  • Intractable nausea and vomiting
  • Intractable pain
  • Complications: sepsis/shock, acute kidney injury, abscess formation, emphysematous changes.
  • Inability to care for self (encephalopathy, weakness).

Enhancing Healthcare Team Outcomes

Acute cystitis is often managed by an interprofessional team that includes a primary care provider, nurse practitioner, internist, urologist, and a nephrologist. It is important to understand that most simple cases of cystitis resolve quickly with treatment, but if there is a persistence of symptoms, admission is recommended.

There are many things to consider when treating cystitis. The choice between agents should be individualized and depends on the duration of treatment as well as the possible organism involved. According to guidelines, there is no single, best agent to treat acute uncomplicated cystitis. Choosing an antibiotic depends on its effectiveness, the risk of adverse effects, resistance rates, and propensity to cause collateral damage; furthermore, physicians should consider cost, availability, and patient factors, such as allergy history. On average, patients will experience symptom relief within 36 hours of the beginning treatment. (Level V)


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