Quiz 106, March 12th, 2021

Welcome to the 106th FOAMed Quiz.

 

Case courtesy of Dr Piotr Gołofit, Radiopaedia.org, rID: 46128

Question 1

A 74-year-old man presents to the ED with a painful left arm after a fall. The X-ray shows a comminuted humeral shaft fracture.

What is the most frequently damaged nerve in this injury and which clinical finding corresponds?

Nerve:

A: Radial Nerve

B: Ulnar Nerve

C: Median Nerve

Finding:

1: Claw hand

2: Ape hand

3: Wrist drop

The correct answer is A – 3.

This week ALiEM discussed the humeral shaft fracture.

The most commonly injured nerve, in about 12% of humeral shaft fractures, is the radial nerve. Most of these nerve injuries will recover spontaneously.

The radial nerve runs along the spiral groove of the humerus. It provides motor innervation to the extrinsic extensors of the wrists and hands; therefore radial nerve palsy can lead to a wrist drop.

SplintER Series: A Case of Arm Pain

Source image: www.pixabay.com

Question 2

West Nile Virus (WNV) is a mosquito-borne flavivirus and neuropathogen.

Which of the following statements is true about this virus?

A: 80% of cases are asymptomatic

B: The virus is indigenous to Africa only

C: Most human infections with WNV are due to human to human transmission

D: Available evidence supports aciclovir as an effective therapeutic agent

The correct answer is A

80% of cases are asymptomatic while 20% develop symptoms. The virus is indigenous to Africa, Asia, Europe, and Australia. Most human infections with WNV are due to mosquito bites and not due to interhuman transmission. Therapeutic agents that have been considered include IVIG, monoclonal antibodies, corticosteroids, and aciclovir. Data to support the use of these agents is lacking.

West Nile Virus

Source image: www.pixabay.com

Question 3

Previous trials such as the TRISS-trial, TRICC and TRICS-III-trial  demonstrated that a restrictive blood transfusion strategy was non-inferior to a liberal transfusion strategy in patients with septic shock, patients admitted to the ICU and patients undergoing cardiac surgery respectively.

The presence of anaemia in patients with acute coronary syndromes is associated with worse outcomes. For that reason, blood transfusions in patients with anemia and acute coronary syndromes are often performed.

The recently published randomized controlled REALITY-trial is about patients with acute myocardial infarction and a haemoglobin (Hb) between 7 and 10 g/dL during admission. The authors compared liberal (transfusion if Hb <10g/dL with target Hb >11g/dL) vs restrictive transfusion (transfusion if Hb <8 g/dL with target Hb >11g/dL) strategies in patients with acute myocardial infarction and anaemia.

Their primary outcome was 30 day MACE (composite of all-cause death, stroke, recurrent myocardial infarction, or emergency revascularization prompted by ischemia).

What did the authors find?

A: MACE at day 30 occurred significantly less often in the liberal transfusion group compared to the restrictive transfusion group

B: MACE at day 30 was not significantly different between the liberal transfusion group compared and the restrictive transfusion group

C: MACE at day 30 occurred significantly more often in the liberal transfusion group compared to the restrictive transfusion group

The correct answer is B

The REALITY trial was covered by Celia Bradford on The Bottom Line this week.

A total of 668 patients were randomised (mean age 77 years, 57.8% male, 70% NSTEMI, 30% STEMI).

MACE at day 30 was not significantly different in the liberal transfusion group compared to the restrictive transfusion group.

REALITY

Source image: https://hqmeded-ecg.blogspot.com

Question 4

Your 65-year-old patient presents with ongoing chest pain for 2 hours. Nitroglycerin did not bring any relief. His ECG is shown above.

Which of the following coronary arteries is likely to be occluded?

A: Right coronary artery (RCA)

B: Left circumflex artery (Cx)

C: Left anterior descending (LAD)

D: Left main coronary

The correct answer is C

De Winter’s T-waves were covered on dr. Smith’s ECG blog last week.

De Winter’s T-waves typically present as ST depression and peaked T waves in the precordial leads.

This pattern is seen in about 2% of acute LAD occlusions.

Source image: www.cdc.gov

Question 5

Most people know anthrax as a biological weapon (powdered letters).

Which of the following statements about anthrax is correct?

A: Overall mortality of anthrax is about 80%

B: Human-to-human transmission of anthrax is responsible for about 5% of inhalational anthrax cases

C: Gastrointestinal anthrax is a result from eating undercooked meat from an infected animal

D: Cutaneous anthrax presents as a disproportionately painful ulcerating vesicle

The correct answer is statement C.

This week’s EMdocs’ toxcard was about Bacillus anthracis.

Animals (usually cattle) are infected through spores which are found in soil and which are very resistant to environmental changes. Humans can be infected by four different routes of exposure. Human-to-human transmission is non-existent.

Cutaneous exposure is the most common (95%) by entering of spores through a superficial laceration. Other routes of exposure are injectional (associated with intravenous drug use), inhalational and gastrointestinal.

Inhalational and gastrointestinal anthrax have the highest mortality rates of up to 50-80%, cutaneous and injectional anthrax have lower mortality rates (5-30%).

Cutaneous anthrax presents as papules that become ulcerating vesicles. These lesions are usually painless.

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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