June 2018 Imaging Case of the Month

Michael B. Gotway, MD

Department of Radiology

Mayo Clinic Arizona

Scottsdale, AZ USA

Imaging Case of the Month CME Information  

Completion of an evaluation form is required to receive credit and a link is provided on the last panel of the activity.

0.25 AMA PRA Category 1 Credit(s)™

Estimated time to complete this activity: 0.75 hours

Lead Author(s): Michael B. Gotway, MD. All Faculty, CME Planning Committee Members, and the CME Office Reviewers have disclosed that they do not have any relevant financial relationships with commercial interests that would constitute a conflict of interest concerning this CME activity. 

Learning Objectives: As a result of completing this activity, participants will be better able to:

1. Interpret and identify clinical practices supported by the highest quality available evidence.
2. Establish the optimal evaluation leading to a correct diagnosis for patients with pulmonary, critical care and sleep disorders.
3. Translate the most current clinical information into the delivery of high quality care for patients.
4. Integrate new treatment options for patients with pulmonary, critical care and sleep related disorders.

Learning Format: Case-based, interactive online course, including mandatory assessment questions (number of questions varies by case). Please also read the Technical Requirements.

CME Sponsor: University of Arizona College of Medicine at the Arizona Health Sciences Center.

Current Approval Period: January 1, 2017-December 31, 2018

Clinical History: A 63-year-old non-smoking woman presented with complaints of nausea, vomiting and abdominal pain, which prompted CT of the abdomen and pelvis (images not shown). The CT of the abdomen and pelvis disclosed several small basilar nodules, for which dedicated thoracic CT (Figure 1) was performed. 

 

Figure 1. Panels A-H: Representative images from unenhanced axial thoracic CT displayed in lung windows. Lower panel: video of thoracic CT in lung windows.

Which of the following represents the most accurate assessment of the thoracic CT findings? (click on the correct answer to be directed to the second of nine pages)

1. Thoracic CT shows bibasilar fibrotic-appearing opacities
2. Thoracic CT shows cavitary pulmonary lesions
3. Thoracic CT shows multifocal bronchiectasis
4. Thoracic CT shows multifocal ground-glass opacity
5. Thoracic CT shows small pulmonary nodules

Cite as: Gotway MB. June 2018 imaging case of the month. Southwest J Pulm Crit Care. 2018;16(6):311-23. doi: https://doi.org/10.13175/swjpcc069-18 PDF 

Medical Image of the Week: Elemental Mercury Poisoning

Figure 1. Panel A: Abdominal x-ray showing radiopaque matter. Panel B: Repeat x-ray after colonoscopy.

A 34-year-old woman presented to the Emergency department with abdominal pain after ingestion of an unknown liquid that family felt might be poisonous. The patient had a past history of prior suicide attempts, as well as a history of polysubstance and alcohol abuse. The patient was confused, tangential and a difficult historian. The patient had a heart rate of 72, was normotensive, and had an oxygen saturation of 100% on room air.  She was confused and answered questions intermittently. The remainder of her physical examination including her neurological exam was normal. The initial serum chemistry, anion gap, lactate, liver function tests were normal. Urine drug screen was positive for benzodiazepines, for which the patient was prescribed. An abdominal x-ray was performed showing a radiopaque substance in the abdomen (Figure 1A). It was eventually determined she ingested elemental mercury. Blood levels were elevated, and she did eventually have hematochezia. Colonoscopy was performed which removed some of the metallic liquid mercury (Figure 1B).

Mercury in any form is poisonous, with mercury toxicity most commonly affecting the neurologic, gastrointestinal (GI) and renal organ systems (1). Poisoning can result from mercury vapor inhalation, mercury ingestion, mercury injection, and absorption of mercury through the skin.

Elemental mercury is poorly absorbed after ingestion but easily vaporizes at room temperature and is well absorbed (80%) through inhalation. Once absorbed elemental mercury is mostly converted to an inorganic divalent or mercuric form by catalase in the erythrocytes. This inorganic form has similar properties to inorganic mercury (e.g., poor lipid solubility, limited permeability to the blood-brain barrier, and excretion in feces).

Treatment of mercury toxicity consists of removal of the patient from the source of exposure, supportive care, and chelation therapy. Our patient had limited symptoms, and for this reason, chelation therapy was not performed. She made an uneventful recovery after discharge to psychiatry. Her blood levels eventually returned to normal in a few months.

Michel A. Boivin, MD

Pulmonary/Critical Care/Sleep Medicine

Department of Internal Medicine

University of New Mexico

Albuquerque, NM USA

Reference

1. Olson DA. Mercury poisoning. Medscape. August 14, 2017. Available at: https://emedicine.medscape.com/article/1175560-overview (accessed 5/22/18).

Cite as: Boivin M. Medical image of the week: Elemental mercury poisoning. Southwest J Pulm Crit Care. 2018;16(5):287-8. doi: https://doi.org/10.13175/swjpcc067-18 PDF