Here’s the final section of a 2-part series on some PoCUS pearls learned along my 1 year fellowship.
5. Trust the gut.
This year, I’ve seen multiple presentations of cholecystitis. Let’s take a look at a slam dunk diagnosis. The following is a patient who presented with RUQ pain, vomiting, fever:
The sonographic Murphy’s sign was positive. Here are the findings consistent with cholecystitis: we can see a non-mobile stone from the supine position to the left lateral decubitus position, and a thickened gallbladder wall. A reminder that wall thickness should be assessed at the most anterior portion of the GB to avoid enhancement artifact. Additionally, there is evidence of pericholecystic fluid.
What about some more subtle cases? I’ve come across 2 patients with RUQ pain, vomiting and no other systemic symptoms. Neither had evidence of leukocytosis and all LFTs were normal.
Here is the first patient’s scan:
The sonographic Murphy’s sign was positive but there were no other findings consistent with cholecystitis. Which didn’t stop the team from consulting general surgery as presence of gallstones and a positive sonographic Murphy’s sign has a 92% positive predictive value for cholecystitis. A radiology US was requested but the final read was negative for cholecystitis. What happened next? The patient was nonetheless taken to the OR and found to have an acutely inflamed gallbladder as per surgical and pathological reports.
What about this 2nd patient?
This patient presented with epigastric pain, nausea and emesis. Her bedside US revealed a positive sonographic Murphy’s sign and a non-mobile stone. The working diagnosis was again cholecystitis. A radiology US was performed but was negative for cholecystitis. The surgical team was nevertheless consulted. Operative and pathological findings were again consistent with acute cholecystitis.
Why were these 2 cases not consistent between PoCUS and radiology US? There have been theories that managing the patient’s pain may negate the sonographic Murphy’s sign. There is however, a paucity of good evidence that this is the case. In the above 2 cases, both patients had received analgesia and had a significant decrease in their pain once the radiology US was performed. The take home point here: be aware that PoCUS for cholecystitis may not be congruent with radiology US… and trust the gut findings!
6. Beware of uncanny mimics… and use PoCUS to rule in pathology.
PoCUS may help you expose some masqueraders! It’s the case for this previously healthy 34 year old man who presented with worsening low back pain radiating to the left groin and thigh. There was no history of trauma, nor any systemic symptoms. He reported decreased pain in the prone position. What else could this positional type of low back pain with radiculopathy possibly be? On examination of his dermatomes, it was noted that the left thigh appeared somewhat edematous… What would you consider at this time?
Of course, PoCUS of the left lower extremity deep venous system was performed:
A radiology US confirmed the presence of a DVT extending from the common iliac vein into the superficial femoral vein. Which leads to another important PoCUS point: most applications of PoCUS should be used to rule in pathology, as is the case for DVTs.
7. You will find pathology… that may warrant further investigations.
The more you scan, the more you may stumble upon unexpected findings. How best to tackle these findings? It’s difficult to apply a catchall rule of obtaining same day radiology US or CT scans or immediate referral. Some of the most common findings which may warrant outpatient, elective scans include renal cysts. But what to do about this 56 year old woman presenting with sudden onset left flank pain, scant hematuria, some nausea, no fever, vomiting or other symtptoms?
Here’s her unaffected side:
And here’s her affected side…
What to make of this kidney? I was on a mission to find left-sided hydronephrosis, and was puzzled when I couldn’t find any signs of such and instead found this complex, irregularly-shaped kidney… The safe thing to do in such a case is to obtain formal imaging. A CT scan was thus obtained:
The patient had renal cell carcinoma. In this case, PoCUS helped broaden my differential but was also a reminder that certain findings warrant further imaging.
Here’s another example. An 83 year old woman with a history of dementia and breast cancer collapsed on her way to an outpatient mammogram. It’s unclear whether a pulse check was performed but she received 1 round of CPR and seemed to regain consciousness. In our resuscitation bay she remained altered and no history was extractable from her. However, she did seem to be clutching at her lower abdomen. She was tachycardic, hypotensive, cyanotic. Did she have a ruptured AAA? Views of the abdomen were obstructed by gas… Did she have a PE? Cardiac views did not reveal any secondary signs of this…
But what about these scans of her LUQ?
When something can’t immediately be explained, it can be easy to simply ‘file away’ this information. Or, we may even try to interpret findings in favour of something else (example, “this is probably stomach content!”); otherwise known as confirmation bias. Be weary of this! And be weary of bizarre PoCUS findings such as that seen in the LUQ. Once stabilized, the patient was sent for a CT of the abdomen and pelvis. Diagnosis? Ruptured splenic artery aneurysm!
8. Have screen awareness.
Do you remember those med school days when you were taught to systematically go through CXR interpretations? I think there is merit in applying this approach to certain PoCUS scans. Sometimes it pays to take a look beyond the area of interest. Here’s an example of this concept: a previously healthy 37 year old male presented (for the 2nd time) with a few weeks of pleuritic chest pain, fever and cough. He had a normal CXR 2 weeks prior but had persistent symptoms. A repeat CXR on his 2nd visit again failed to show evidence of pneumonia. A cardiac PoCUS was performed:
In a young, healthy patient without any previous medical conditions, cough, fever, and pleuritic chest pain would either be due to pneumonia or pericarditis until proven otherwise. However, there was clearly no evidence of a pericardial effusion on this scan. Was there something else that caught your eye when looking beyond the pericardium? Take another look if you didn’t spot it…
This patient had a hepatic abscess. It’s more clearly delineated in this view of the RUQ:
This may have been missed if we hadn’t looked beyond our area of interest, the pericardium. An interventional radiology US was obtained which confirmed the presence of a hepatic abscess and targeted aspiration was performed. Sometimes it pays to take in the bigger picture!