TREATMENT
Ascites
First-line treatment for patients with ascites includes dietary sodium restriction (maximum 2,000 mg/d) and oral diuretics (spironolactone with or without furosemide).2,5 This regimen is effective for 90% of patients.5 Typically, a ratio of 100 mg of spironolactone to 40 mg of furosemide is ideal to promote adequate diuresis while maintaining normal electrolyte balance. Doses can be increased every three to five days, with maximum doses of 400 mg/d of spironolactone and 160 mg/d of furosemide.2 Renal function and sodium levels should be monitored closely and diuretic dosing adjusted based on clinical presentation to avoid volume depletion, which puts patients at risk for AKI and hyponatremia.5,12 Diuretics should not be given in cases of AKI (creatinine level > 2 mg/dL), kidney failure (ie, patients on dialysis), acute infection, uncontrolled encephalopathy, or severe hyponatremia (sodium < 120 mEq/L).2,4
Refractory ascites
Approximately 10% of patients develop refractory ascites when the condition becomes unresponsive to diuretics or when adverse effects preclude the use of diuretics.5 In such cases, large-volume paracentesis (> 5 L removed) is the standard treatment. The patient should be monitored closely during the procedure; blood pressure can decrease drastically due to the large fluid loss. Vital signs should be checked every 15 min to 30 min for the first hour postprocedure, and then hourly if signs remain stable. Albumin should be administered (6-8 g/L of fluid removed) to increase circulating fluid volume.2 The patient’s renal function (ie, serum creatinine level and urinary output) should also be monitored closely, as dehydration and/or AKI can occur.4 Complications of paracentesis are uncommon but may include bleeding, infection, and bowel perforation. No data support the routine administration of blood products before paracentesis.2
Treatment of SBP
Broad-spectrum antibiotics, particularly cefotaxime, are effective against approximately 94% of the bacterial flora associated with SBP. Initial treatment with cefotaxime (or ceftriaxone, if cefotaxime is unavailable) at a dose of 2 g IV q8h for seven days is recommended, unless or until culture results identify susceptibility to a specific narrow-spectrum antibiotic.2,4,7,9 After completion of a total of seven days of IV antibiotics, it is cost effective and safe to transition clinically improved patients to an oral antibiotic for SBP prophylaxis (see discussion below).9
A repeat paracentesis performed 48 hours after treatment is initiated is useful in assessing response to treatment, defined as a ≥ 25% decrease in ascitic fluid PMN count.7
Even if the infection is successfully treated, one-third of patients who have an episode of SBP develop renal failure; those who experience a recurrence of SBP within one year have a 50% to 60% mortality rate.4,7,9,14 This is because infection causes vasodilation, with a concomitant decrease in blood volume and compensatory activation of renal vasoconstrictors, so renal function worsens.
A randomized controlled trial found that patients treated with IV cefotaxime with albumin in doses of 1.5 g/kg on day 1 and 1 g/kg on day 3 had significantly lower rates of AKI and mortality than patients who received cefotaxime alone.15 An albumin infusion, given in conjunction with antibiotics, improves blood volume, enhances renal perfusion, and has been shown to decrease mortality from SBP from 29% to 10%.2,12,16
CASE For small bowel obstruction, the patient was made NPO and a nasogastric tube was placed for 36 hours. During this time, he had a bowel movement, diet was advanced, and the obstruction resolved.
At the same time, the patient was started on IV cefotaxime 2 g q8h for treatment of SBP, along with IV albumin and fluids. Diuretics were withheld because of impaired kidney function.
Ascitic fluid was cultured, and Streptococcus viridans was identified. After consultation with the infectious disease service, broader-spectrum vancomycin was added to the patient’s IV antibiotic regimen 24 hours after admission while culture results finalized. Cultures were analyzed after three days and found to be susceptible to ceftriaxone, which was administered 2 g IV q24h for three days, for a total of seven days of IV antibiotics.
The patient’s AKI improved after treatment with IV antibiotics, fluids, and albumin. Seventy-two hours after admission, repeat paracentesis revealed a significant decrease in white blood cells; cultures were negative for infection.
Neutrocytic ascites
In some cases, the bacteria count in ascitic fluid is so low that cultures may be negative.4 This is termed neutrocytic ascites, characterized by an elevated PMN cell count with negative cultures. Patients with neutrocytic ascites should be treated as though they have SBP.2,7
Prophylactic antibiotics
Of patients successfully treated for SBP, 69% will experience another episode within one year; many of these cases can be prevented with the use of prophylactic antibiotics. Historically, quinolones were used for SBP prophylaxis, and they are cost-effective. However, multiorganism drug resistance hasoccurred after quinolone prophylaxis, especially if given long-term.2,4,7
Alternatives to quinolones include trimethoprim/sulfamethoxazole double strength or ciprofloxacin 500 mg/d.2 Renal dose adjustment is necessary for patients with acute or chronic kidney disease and can usually be guided by a pharmacist. One study found norfloxacin and trimethoprim-sulfamethoxazole to be similarly effective for SBP prevention, but trimethoprim-sulfamethoxazole was noted to be more cost-effective.10
In patients with active gastrointestinal bleeding, IV ceftriaxone 1 g/d for seven days can be given for SBP prevention. In patients with low ascitic protein and/or history of prior SBP, norfloxacin 400 mg/d is an option.
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