Diagnostic challenges from your case files

CASE
Ms. C. is a 23-year-old nonsmoker who presented to the clinic with a history of recurrent urinary tract infections (UTIs) for approximately 18 months. Her primary care physician had treated these infections empirically with antibiotics, based on Ms. C.'s symptoms of pelvic pain and pressure, dysuria, and increased frequency. Urinalysis and culture of a recent clean catch urine specimen revealed 5 to 7 RBCs per high-power field and was negative for WBCs and bacteria. A urine culture showed no growth after 48 hours. The physician prescribed another antibiotic and phenazopyridine to relieve bladder symptoms and told Ms. C. that it could be the beginning of another infection. Ms. C. explained that the symptoms were causing sexual problems in her relationship with her boyfriend and interfering with her college studies. She denied back pain, nausea, vomiting, fever, and sexually transmitted disease (STD). She reported that symptoms also worsened just before menstruation.

Testing Flexible cystoscopy performed in the office revealed increased vasculature of the bladder wall with mild submucosal hemorrhage.

WHAT IS YOUR DIAGNOSIS?

Bladder cancer
Bladder stones
An STD
Interstitial cystitis
Chronic UTI

DISCUSSION

Ms. C. has interstitial cystitis (IC), which affects more than 700,000 Americans, of whom 90% are women.1 The exact cause is unknown, although the condition may be due to an autoimmune response, an allergic condition, or previous UTIs or viral infections.1 Each of these represents a suggestive cause for the breakdown of the protective glycosaminoglycan layer of the bladder, which allows irritating chemical substances in urine to permeate the bladder wall, stimulating pain receptors and causing hyperalgesic inflammatory symptoms. This state of permeability is also known as leaky bladder syndrome.

Common symptoms of IC include dysuria, pelvic pain or pressure, pain during or after intercourse, and increased urgency and frequency. Symptoms may change as the bladder fills and empties and may worsen before menstruation or with stress. Patients may have periods of remission that can last months or years. Symptoms have been noted to improve in women who become pregnant. Acidic beverages as well as some foods that are high in potassium can aggravate symptoms.

Diagnosis IC is a diagnosis of exclusion because its symptoms mimic those of UTIs, some STDs, bladder cancer, and other pelvic disorders. The workup should include a complete pelvic exam, STD testing, urinalysis, microscopy, urine culture, cystoscopy, a potassium sensitivity test, and, possibly, a bladder biopsy to rule out cancer. Urinalysis may show mild hematuria, and cultures are negative for bacterial growth. Findings on cystoscopy include increased or prominent vasculature and submucosal hemorrhage. Potassium sensitivity testing is an effective office-based diagnostic test for IC: 75% of patients with IC have increased pain and urgency upon instillation of potassium chloride.

Treatment: No cure is available for IC, and treatment is aimed at relieving symptoms. Exercise and physical therapy can help reduce pelvic pain and stress.4 Six weekly or biweekly bladder irrigations with dimethyl sulfoxide (DMSO; Rimso-50) may alleviate pain and inflammation for several months. Oral pentosan polysulfate (Elmiron) may repair the bladder lining and relieve symptoms, but improvement may take as long as 3 to 6 months. Other oral agents used to treat symptoms of IC include tricyclic antidepressants, urinary tract analgesics and antispasmodics, antihistamines, NSAIDs, and opioid analgesics.

Comment: Until research advances and new ways to relieve symptoms are found, treatment is aimed at reducing symptoms and improving quality of life. Patients benefit from emotional support from family, friends, and health care providers.