Category Archives: cases

FAST five ways

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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

What the Heck 3

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The Shadow Knows What the Heck 3So we are scanning the left thorax in a patient with shortness of breath, in an effort to assess for pleural effusion. The following video was obtained:

The operator correctly noted the presence of a pleural effusion, and a bit of lung tissue can be seen towards the left side of the screen floating in fluid. In addition, there are THREE shadows evident, each from a different source. Can you spot them?

large LUQ pic What the Heck 3

So let’s take these one at a time, with labels:

large LUQ piclabels What the Heck 3

Shadow A

Is the easiest one. It extends almost from the first pixel at the top of the screen down to the far field. We can’t even see the characteristic echotexture of skin or subcutaneous tissue in the near field. There’s no contact here between the transducer and skin, possibly due to:

  • the probe not touching at all
  • clothing or an EKG lead getting in the way
  • not enough gel (the novice’s answer to everything but sometimes still true)

Shadow B

The most interesting one of the bunch. Probably two major factors at work here. First, this section of diaphragm is a particularly bright reflector so it can create a shadow behind it due to the sheer amount of reflection occurring. Second, the density difference between the diaphragm and pleural effusion is creating a refraction artifact, often referred to as an edge artifact. Beams of sound which were roughly parallel as they struck this interface get bent at different angles based on whether they hit the dense diaphragm or the less dense fluid. The space in between the formerly tightly spaced beams is displayed as blackness, or the absence of returning echoes.

Shadow C

That’s a rib shadow. Did you know that ribs grow back if you remove them?

 

Case- vaginal bleeding

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This young healthy woman presented in her first trimester of pregnancy with lower abdominal pain and vaginal bleeding. She had diffuse abdominal tenderness and was mildly tachycardic with a normal blood pressure. After IV access was established, labs and blood bank sample were sent, and the following ultrasound of the right upper quadrant was obtained:

So there’s a bit of free fluid in Morison’s pouch. Can we make it more evident for the kids in the back row? The next image was taken with the patient in Trendelenberg position:

That made a pretty big difference.

In this sagittal view of the uterus the bladder is visible to the screen right; there is free fluid in the pelvis just to the left of this, and it can be seen to move with probe pressure on the lower abdomen.

Thus a diagnosis of ruptured ectopic pregnancy was strongly suspected, and the patient underwent emergency laparoscopy with the obstetrics service.

Check out our pelvic ultrasound and FAST tutorials for more details on performing these assessments.

 

What the Heck 2

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This patient presented with diffuse abdominal pain, tachycardia, and peritonitis on physical examination. A FAST exam was performed to assess for free intraperitoneal fluid, and the following view of was obtained transversely in the pelvis.

First, just look at the still image and make your best guess. Then press play:

Did the large anechoic structure in the near field look like the bladder? Or was it the anechoic area in the far field? The operator was thrown off a bit by the complex echoes within the anterior structure. Remember the bladder is going to conform to the shape of the pelvis as it enlarges, so it will take on a characteristic square/trapezoidal shape in transverse orientation. But for the same reasons free fluid will take the same shape. Through the sweep from cranial to caudal you’ll notice two fluid collections; the anterior one seemed to have much more internal echo and debris. Don’t assume that’s the peritoneal fluid- urine can also look that way.

This was the sample obtained when a Foley catheter was inserted into the bladder:

UTI 500x380 What the Heck 2This definitely looked (and smelled) better sonographically.

Here is the longitudinal (sagittal) view through the pelvis:

As usual, the sagittal view gives a better overview of the anatomy of the pelvis. When using the transverse view of the pelvis, you can miss small amounts of pelvic fluid more easily, confuse fluid collections for the bladder, and make incorrect assumptions. Just more support for the sonographic dogma of imaging everything in two planes.

Case resolution:

CT scan confirmed free intraperitoneal fluid but no free air or other signs of bowel perforation. The hemoglobin was stable through several assessments. The patient had an obvious urinary tract infection and renal failure on laboratory evaluation. Thus the fluid was thought to be new onset of ascites in the setting of urosepsis and mult-organ dysfunction.

Tips:

  • Always image anatomy in at least two planes, and fan through anything that isn’t moving.
  • Rethink assumptions when the anatomy doesn’t look as it should. For example, an oddly-shaped or highly echoic bladder may not be bladder at all, or it might just be an abnormal bladder.
  • ALWAYS clean the machine and put it back where you found it when you are done.

I had to throw that in there, sorry.

 

Case- Abdominal pain

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Patient with history of hypertension presents periumbilical abdominal pain radiating to the back. Minimal abdominal tenderness, no rebound or guarding, though  a pulsatile mass is felt.

The following ultrasound is obtained:

As the title suggests, the patient was diagnosed with an abdominal aortic aneurysm and vascular surgery was consulted.

We’re experimenting a bit with the GMEP.org system. It’s a great educational collaborative run by the folks who brought you Life in the Fast Lane. Worth checking out.

As you may know, we have a Vimeo channel with a growing video archive as well. Our goal is to make this site and its content as helpful and accessible a possible, so please let us know how we can improve!

What The Heck 1

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This patient presented with right upper quadrant abdominal pain. There was RUQ tenderness on exam, but no fever, rebound or Murphy sign. A point-of-care ultrasound was performed to assess for signs of cholecystitis and the following image was obtained. This prompted the operator to ask, “What the heck?”

GB1 500x376 What The Heck 1
What structures are visible here? How could you differentiate them? More after the break!

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XRS- Rib pain

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32 year old female with no past medical history presents with cough for two weeks, no fever, no sputum. Multiple sick contacts with same symptoms at work. She acutely presents with left rib pain for several days.  She reports no trauma, and noted the sharp, positional pain during a fit of coughing. Her vital signs are all within normal limits. She is breathing comfortably, with good air movement, no wheezes, rales, or ronchi. She displays point tenderness over her anterior left 8th rib at the anterior axillary line.  A chest x-ray was ordered; images are below.

 

Sonopalpation of the tender area revealed the following:

Untitled from Sinai EM Ultrasound on Vimeo.

 

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