The FAST exam is generally described as a trauma assessment (hence the acronym). But it is often used as a metanym to mean any assessment of the peritoneum for fluid. In fact when I was a resident folks would often say, “let’s FAST that gallbladder,” or “get the FAST machine so we can put that central line in.” And we didn’t have Twitter.
Anyway, here are a few cases where the “FAST” was used in a non-trauma patient to assess the peritoneum:
Cirrhotic with abdominal pain and tenderness:
who was found to have ascites, and spontaneous bacterial peritonitis
Lower abdominal pain in pregnancy:
who was found to have hemoperitoneum from a ruptured ectopic pregnancy
Diffuse abdominal tenderness in a healthy ten-year-old:
who was found to have idiopathic seromas of the peritoneum, pleura, and pericardium!
Shortness of breath and abdominal distension:
which turned out to be massive abdominal abscesses
Diffuse abdominal tenderness and distension after hysteroscopy:
which was complicated by a bowel perforation; hence fecal material throughout the peritoneum
Take home points:
- Assessment of the peritoneum greatly aids medical and surgical diagnoses
- Fluid appears black (anechoic) on ultrasound. Very difficult to tell what TYPE of fluid by appearance alone
- Your clinical assessment must guide the differential diagnosis for your ultrasound findings