Diagnostic Ultrasound - Abdomen and Pelvis

Diffuse Peritoneal Fluid
Differential Diagnoses:
Abdominal Wall/Peritoneal Cavity
DIFFERENTIAL DIAGNOSIS
Common
• Transudate
○ Portal Hypertension
– Cirrhosis
– Portal Vein Thrombosis
– Budd-Chiari Syndrome
○ Heart Failure
○ Renal Failure: Acute or Chronic
○ Fluid Overload
Less Common
• Exudate
○ Peritoneal Inflammation
– Pancreatitis, Polyserositis
○ Peritonitis
– Pyogenic Peritonitis
– Tuberculosis Peritonitis
○ Carcinomatosis
• Hemoperitoneum
○ Post-Traumatic or Ruptured Aneurysm
○ Ruptured Ovarian Cyst or Ectopic Pregnancy
○ Ruptured Intraabdominal Tumor
– Hepatic, Splenic, and Ovarian are Most Common
Rare but Important
• Chylous Ascites
• Urine, Bile, CSF
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
• Simple ascites = anechoic fluid = transudate
○ Other causes: Dialysate fluid, CSF from ventriculoperitoneal
shunt
• Complicated ascites = exudate or complicated transudate
○ Infection, malignancy, hemorrhage, or chylous ascites
– Echogenic fluid and debris
– Septa suggest subacute to chronic nature
Helpful Clues for Common Diagnoses
• Transudate
○ Look for cause: Cirrhotic liver, engorged hepatic veins
from heart failure, chronic renal parenchymal disease
Helpful Clues for Less Common Diagnoses
• Hemoperitoneum
○ History of trauma ± solid organ laceration/fracture, aortic
injury
○ Irregular or collapsed ovarian cyst in a female of
reproductive age
○ Ruptured tumors (hepatic, ovarian, splenic) are usually
large and present with acute severe abdominal pain
• Pyogenic Peritonitis
○ Marked echogenic peritoneal fluid
○ Dilated, fluid-filled bowel with ↓ peristalsis
○ Clinical pictures of infection
• Carcinomatosis
○ Peritoneal deposits, omental cake, other evidence of
metastases or primary
• Tuberculosis Peritonitis
○ Diffuse omental thickening, nodules or mass, debris,
septation; may closely mimic carcinomatosis
Helpful Clues for Rare Diagnoses
• Chylous Ascites
○ Disruption of abdominal lymphatics can be traumatic or
atraumatic
– Congenital lymphatic anomalies most frequent in
childhood
– Malignancy 2nd most common cause (lymphoma
most common)
– Trauma, surgical injury, radiation
– Cirrhosis: Increased abdominal pressure resulting in
leakage of lymph
– Inflammatory: Pancreatitis, mycobacterial infection
(Left) Longitudinal ultrasound
of the right upper quadrant
shows anechoic ascites ſt in a
patient with a nodular
cirrhotic liver . Bowel loops
are noted . (Right)
Transverse ultrasound of the
left lower quadrant shows
complex septated ascites ſt.
Aspiration is required for
diagnosis.
Cirrhosis
Peritoneal Inflammation
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