Ascites and Spontaneous Bacterial Peritonitis

GI NOTES

Ascites and Spontaneous Bacterial Peritonitis

Key points

Do a diagnostic paracentesis for new ascites, for every admission with cirrhosis and ascites, and for any deterioration (fever, pain, encephalopathy, AKI, GI bleeding).
SAAG of 1.1 g/dL or higher means portal hypertension. Ascitic total protein below 2.5 g/dL points to cirrhosis; 2.5 or higher to a cardiac cause.
SBP is an ascitic neutrophil (PMN) count of 250 cells/mm3 or more. Treat with a third-generation cephalosporin plus IV albumin.
First-line ascites therapy: 2 g/day sodium restriction plus spironolactone and furosemide in a 100:40 ratio.
Give 6 to 8 g of albumin per liter removed when a paracentesis takes off more than 5 liters.

1. Diagnostic paracentesis

Coagulopathy and thrombocytopenia are not contraindications; routine plasma or platelets are not needed.
Always send: cell count with differential, albumin, total protein. Inoculate blood culture bottles at the bedside (about 10 mL each).
When indicated: glucose, LDH, Gram stain, amylase, cytology, triglycerides, AFB/adenosine deaminase.

SAAG	Ascitic protein	Most likely cause
1.1 or higher	Below 2.5 g/dL	Cirrhosis
1.1 or higher	2.5 g/dL or higher	Heart failure, Budd-Chiari syndrome
Below 1.1	2.5 g/dL or higher	Peritoneal carcinomatosis, tuberculosis, pancreatic ascites
Below 1.1	Below 2.5 g/dL	Nephrotic syndrome

2. Managing ascites

FIGURE: STEPWISE MANAGEMENT OF CIRRHOTIC ASCITES

Grade 2 or 3 ascites

Sodium restriction 2 g/day; stop NSAIDs

Spironolactone 100 mg + furosemide 40 mg daily, titrate to max 400 mg + 160 mg

Controlled: maintain, monitor sodium, potassium, creatinine

Refractory: serial large-volume paracentesis with albumin, TIPS, transplant evaluation

Original diagram based on the AASLD 2021 practice guidance.

Fluid restriction only if serum sodium falls below 125 mmol/L.
Target weight loss: about 0.5 kg/day without edema, up to 1 kg/day with peripheral edema.
Hold diuretics for serum sodium below 125, AKI, worsening encephalopathy, or severe muscle cramps.
Refractory ascites: does not respond to maximal diuretics, or diuretics cause complications. Options are large-volume paracentesis, TIPS in selected patients, and referral for transplant.

Hyponatremia

Common and a marker of poor prognosis (part of MELD-Na and MELD 3.0).
Correct chronic hyponatremia slowly: no more than about 8 mmol/L in 24 hours (4 to 6 if at high risk of osmotic demyelination).

3. Spontaneous bacterial peritonitis

Step	What to do
Diagnose	Ascitic PMN count of 250/mm3 or more, with no surgically treatable source
Antibiotics	Community-acquired: cefotaxime or ceftriaxone for 5 to 7 days. Nosocomial or recent antibiotics: broader coverage (for example piperacillin-tazobactam or a carbapenem) guided by local resistance.
Albumin	1.5 g/kg on day 1 and 1 g/kg on day 3, especially if creatinine above 1 mg/dL, BUN above 30 mg/dL, or bilirubin above 4 mg/dL. Lowers renal failure and mortality.
Reassess	Repeat paracentesis at 48 hours if not improving; PMN should fall by at least 25%.
Look for secondary peritonitis	Total protein above 1 g/dL, glucose below 50 mg/dL, LDH above the serum upper limit, or multiple organisms: get CT and surgical input.

Prophylaxis

Situation	Prophylaxis
GI bleeding in cirrhosis	Ceftriaxone 1 g IV daily, up to 7 days
Prior SBP (secondary)	Long-term oral antibiotic, for example ciprofloxacin or trimethoprim-sulfamethoxazole daily
Ascitic protein below 1.5 g/dL plus advanced liver or kidney dysfunction (primary)	Consider long-term prophylaxis

4. Hepatorenal syndrome (HRS-AKI)

Stage the AKI (rise in creatinine of 0.3 mg/dL or more in 48 hours, or 50% or more over baseline).
Stop diuretics, nephrotoxins and lactulose over-purging; treat infection; give albumin 1 g/kg/day (maximum 100 g) for 2 days.
HRS-AKI if there is no response, no shock, no nephrotoxins, and no structural kidney disease (bland urine, normal ultrasound).
Treatment: terlipressin plus albumin (avoid with hypoxia or volume overload). Alternatives: norepinephrine in the ICU, or midodrine plus octreotide with albumin.
Refer for liver transplant evaluation; HRS predicts high short-term mortality.

5. High-yield pearls

Bedside inoculation of culture bottles increases culture yield from about 50% to about 80%.
SBP is often silent: unexplained encephalopathy or AKI in cirrhosis should prompt a tap.
Avoid NSAIDs in anyone with ascites; they cause diuretic resistance and AKI.
Hemorrhagic ascites: subtract 1 PMN for every 250 red cells per mm3.

Self-check questions

SAAG 1.5 and ascitic protein 3.2 g/dL. Most likely cause?
Ascitic PMN 420/mm3, creatinine 1.4 mg/dL. What do you give?
You remove 8 liters of ascites. How much albumin?
What is first-line drug therapy for HRS-AKI?

Answers: (1) Cardiac ascites (heart failure) or Budd-Chiari syndrome. (2) A third-generation cephalosporin plus albumin 1.5 g/kg on day 1 and 1 g/kg on day 3. (3) About 48 to 64 g (6 to 8 g per liter removed). (4) Terlipressin with albumin, if there is no hypoxia or volume overload.

References

Biggins SW, Angeli P, Garcia-Tsao G, et al. Diagnosis, Evaluation, and Management of Ascites, Spontaneous Bacterial Peritonitis and Hepatorenal Syndrome: 2021 Practice Guidance by the AASLD. Hepatology. 2021;74(2):1014-1048.
Angeli P, Gines P, Wong F, et al. Diagnosis and management of acute kidney injury in patients with cirrhosis: revised consensus recommendations of the International Club of Ascites. J Hepatol. 2015;62(4):968-974.
Wong F, Pappas SC, Curry MP, et al. Terlipressin plus Albumin for the Treatment of Type 1 Hepatorenal Syndrome. N Engl J Med. 2021;384(9):818-828.
de Franchis R, Bosch J, Garcia-Tsao G, et al. Baveno VII: Renewing consensus in portal hypertension. J Hepatol. 2022;76(4):959-974.

For educational purposes only. This note does not replace clinical judgment or local protocols. Check doses against current labeling and institutional guidance.