Quiz 154, May 13

Welcome to the 154th FOAMed Quiz.


Question 1

Source image: first10EM.com

What is the maximum dose of lidocaine without adrenaline for peripheral nerve blocks?

A: 2 mg/kg

B: 3 mg/kg

C: 4.5 mg/kg

D: 6.5 mg/kg

The correct answer is C.

BrownEM Local Anesthetic Systemic Toxicity (LAST) last week.

The maximum dose of lidocaine is 4.5 mg/kg.

LAST the most feared complication of ‘’amide’’ local anesthetics like lidocaine. To minimize the risk of LAST, the smallest effective dose of local anesthetic should be used.

Question 2

Source image: dontforgetthebubbles.com/toddler-fracture/

On this X-ray, a spiral fracture of the tibia can be found.

How is his fracture often called?

A: Toddler’s fracture

B: Neonate fracture

C: Infant fracture

D: Preschool fracture

The correct answer is A.

Pediatric EM Morsels covered tibial shaft fractures last week.

Tibial shaft fractures are the 3rd most common long bone injuries in children.

A toddler fracture is a minimally or undisplaced spiral fracture of the tibia, typically encountered in toddlers. It is the result of low impact trauma and these fractures can be really hard to detect on an X-ray.

Tibial Shaft Fractures in Children

Question 3

Source image: pixabay.com

Your patient presents with progressive weakness and difficulty breathing. He has myasthenia gravis and you suspect a myasthenic crisis with so far an unknown cause.

Which of the following statements is true about the treatment of myasthenic crisis?

A: In rapid sequence intubation, succinylcholine should be used instead of nondepolarizing agents

B: Patients with difficulty breathing should be in supine position as long as possible

C: Plasma exchange is the first-line agent for severe exacerbations

The correct answer is is C.

SinaiEM covered myasthenic crisis last week.

The effect of succinylcholine is unreliable due to reduced acetylcholine receptor density in patients with myasthenia gravis.

Patients with myasthenic crisis have weak diaphragm and will have a higher forced vital capacity when sitting upright, compared to lying down.

Plasma exchange is the first-line agent for severe exacerbation, as it causes improvement in a few days. Intravenous Immunoglobulin (IVIG) needs a couple of weeks to be effective.

Myasthenic Crisis

Question 4

Source image: pixabay.com

Your 2 year old patient presents with a painful elbow after her father lifted her by her arms. You suspect a radial head subluxation (nursemaid’s elbow).

Which of the following reduction techniques is considered to be the most effective?

A: Hyperpronation

B: Supination and flexion

C: Traction

The correct answer is A.

EM Pills blog (in Italian) covered the nursemaid’s elbow last week.

Hyperpronation is considered to have greater effectiveness compared to the supination-flexion maneuver. Furthermore, this maneuver would seem to be less painful for the child.


Question 5


Source image: semanticscholar.org

Point of care ultrasound (POCUS) can be helpful whenever the diagnosis of a radial head subluxation is not clear. Which of the following POCUS signs are found in a nursemaid’s elbow?

A: Twinkle sign

B: Hook sign

C: Donut Sign

The correct answer is B.

The twinkle sign (or twinkling artifact) consists of rapid alternation of color immediately behind an echogenic object, causing false appearance of movement.

The donut sign is seen in intussusception.

The hook sign is caused by ‘’pulling’’ the annular ligament between the radial head and the capitellum. It is seen in longitudinal view


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

Reviewed and edited by Rick Thissen