Quiz 109, April 2nd, 2021

Welcome to the 109th FOAMed Quiz.

 

Source image: www.pixabay.com

Question 1

An 11 year old boy presents to the ED after he fell off his bike. He complains about abdominal pain. He is hemodynamically stable. You wonder what the chance is this boy has intra-abdominal injury (IAI) despite a negative Focused Assessment with Sonography for Trauma (FAST).

What is the posttest (post FAST) probability of IAI according to this recently published systematic review?

A: 1%, IAI is very unlikely

B: 3%, IAI is unlikely, but can be missed

C: 9%, IAI is still a possibility, clinical suspicion warrants further testing

D: 20%, FAST is not useful

The correct answer is C.

This systematic review included a total of 2135 patients, which found FAST had pooled sensitivity of 35%, specificity 96% for IAI.

The results from FAST examinations for IAI showed a pooled sensitivity of 35%, specificity of 96%, LR+ of 10.84, and LR- of 0.64. A positive FAST posttest probability for IAI (63%) and a negative FAST posttest probability for IAI (9%). A positive FAST warrants imaging. A negative FAST does not exclude IAI.

Case courtesy of Dr Matthew Lukies, Radiopaedia.org, rID: 51249

Question 2

Your 75 year old female patient presents after a fall on the right hip. The X-ray shows no signs of fractures, but your patient is not able to mobilise. You know a fracture of the femoral neck can be missed on conventional imaging, but what about other imaging modalities?

Which of the following imaging modalities does not have a sensitivity of 100% (or close to a 100%) according to this paper?

A: CT

B: MRI

C: Ultrasound

The correct answer is A

Both ultrasound and MRI have a sensitivity of 100% for hip fractures . Ultrasound findings include joint effusion, hematoma and fracture line. The sensitivity of CT is about 87 percent.

SplintER Series: A Case of Hip Pain

Source image: www.rebelem.com

Question 3

Ketamine is frequently used in the ED. The standard analgesic dose is 0.1 to 0.3 mg/kg (that is of ketamine, not esketamine). Of course, we occasionally witness neuropsychiatric side effects (like hallucination, agitation).

Which of the following can reduce the rate of these neuropsychiatric side effects?

A: Rapid administration (< 2 minutes)

B: Administration over a short infusion (15-30 minutes)

C: Increasing the dose to 0.6 mg/kg

D: Let the patient listen to heavy metal

The correct answer is B

The NuEM blog covered this paper about Ketamine this week.

A rapid administration (push dose) and higher subdissociative dose increase the chance of neuropsychiatric side effects. I guess listening to heavy metal will have the same effect.

To reduce the rate of neuropsychiatric side effects of analgesic dose ketamine you can slow down the administration. One way to do that is to put the ketamine in a bag of 100 cc NS and administer over 20 minutes.

Source image: www.emdocs.net

Question 4

Which of the following underlying conditions lead to a direct (conjugated) hyperbilirubinemia?

A: Crigler Najjar syndrome

B: Dubin Johnson syndrome

C: Gilbert syndrome

D: G6PD-deficiency

The correct answer is B

EMDocs covered adult jaundice this week.

In Crigler-Najjar syndrome, there is a defect in conjugation of bilirubin and glucuronic acid within hepatocytes, leading to indirect hyperbilirubinemia. Gilbert syndrome is caused by a mutation in the same gene, but unlike Crigler-Najjar syndrome, is benign. G6PD deficiency leads to hemolysis, thus leading to indirect hyperbilirubinemia as well.

Dubin-Johnson syndrome is caused by a defect in the ability to secrete conjugated bilirubin into the bile, leading to direct hyperbilirubinemia. It is usually asymptomatic.

Source image: www.orthobullets.com

Question 5

Your 76 year old patient is admitted after a fall and a fracture of the left femoral neck. About 24 hours after the fall he develops severe respiratory distress and a right hemiparesis. He did not have surgery yet. An X-ray of the chest and CT of the lungs, chest and brain show no obvious cause. The diagnosis fat embolism syndrome is made.

Which of the following treatment options is most widely accepted?

A: Corticosteroids

B: Correction of the fracture

C: Heparin

The correct answer is B

BrownEM covered fat embolism syndrome last week.

The mainstay of treatment of fat embolism syndrome is supportive care. However, early correction of the fracture is considered wise since it is likely to stop formation of new fat emboli.

Although inflammation is thought to have a roll in the development of fat embolism syndrome, there is not enough evidence to support its use. Heparin does not seem to be beneficial either, although it may increase intravascular lipid breakdown.

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This quiz was written by Sophie Nieuwendijk, Denise van Vossen, Gijs de Zeeuw, Nicole van Groningen and Joep Hermans

Reviewed and edited by Rick Thissen