Correspondence

Distinguishing between aortic dissection and Dissecting aneurysm-precise use of new nomenclature

To the Editor,

We’ve read the case report from Linett [1] titled bDissecting Abdominal aortic aneurysm in a young man: an uncommon presentation of abdominal painQ published in the May issue of AJEM. The authors unfortunately used outdated and somewhat confusing nomenclature.

After Morgagni [2] described the Pathological findings, baortic dissectionQ and bdissecting aneurysmQ are phrases used interchangeably in the literature and medical commu- nity. But actually, the definition of dissection is bblood enters into the media or the potential space between intima and media and creates a false lumen which then spreads in an antegrade or retrograde manner within the vessel.Q It doesn’t necessarily imply aneurysmal dilatation in the affected vessel. On the other hand, true aneurysms involve dilatation of all 3 Arterial wall layers. Both the definitions and pathophysiologies of dissection and aneurysm are different. Therefore, the recent review articles [3,4] and the International Classification of Diseases, Ninth Revision, Clinical Modification, in 2001 [5] all suggest that dissecting aneurysm is a misnomer and should not be used anymore. In the selected figures of the article of Linett [1], no obvious aneurysmal dilatation can be found in the dissecting segment. And no dissection can be found in the displayed aneurysm. The low-density crescent lesion is considered to be mural thrombus using the calcified intima as landmark. This also supports the nomenclature change in the Interna- tional Classification of Diseases, Ninth Revision, Clinical Modification, in 2001 [5].

Precise nomenclature is critical to effective Scientific communication, and this case illustrates the need to stay highly current to avoid out-of-date nomenclature and confusion.

Tain Lee, MD

Department of Radiology Taichung Veterans General Hospital

Taiwan Faculty of Medicine

Medical College of Chung Shang

Medical University

Taiwan

I-Chen Tsai, MD

Department of Radiology Taichung Veterans General Hospital

Taiwan

Wan-Chun Liao, RT

Department of Radiological Technology Chung Tai Institute of Health Sciences and Technology

Taiwan

DOI of original article 10.1016/j.ajem.2005.02.007 doi:10.1016/j.ajem.2005.06.002

References

1. Linett LM. Dissecting abdominal aortic aneurysm in a young man: an uncommon presentation of abdominal pain. Am J Emerg Med 2005; 23:383 - 5.
2. Morgagni GB. De sedibus et causis morborum. Venetiis, 1761.
3. Henning RJ, Eikman E, Siddique Patel M. Acute and chronic aortic dissection. Heart Dis 2000;4:231 - 41.
4. Dmowski AT, Carey MJ. Aortic dissection. Am J Emerg Med 1999;17:372 - 5.
5. ICD-9-CM coordination and maintenance committee meeting. Avail- able at: http://www.cdc.gov/nchs/data/icd9/icdp1101.pdf.

Prevalence of Postdural puncture headache after ED performed lumbar puncture^B,BB

To the Editor,

lumbar puncture is a common diagnostic procedur- eperformed by emergency medicine (EM) physicians to evalu- ate patients with a concerning headache or altered mentation.

A common and often debilitating complication of LP is postdural puncture headache (PDPH) or bspinal headache.Q Bier was the first to hypothesize that this severe postural headache resulted from a persistent cerebrospinal fluid leak caused by a dural tear [1,2]. Postdural puncture headache management is difficult and often requires prolonged bed rest, hospital admission, various analgesics (caffeine, opioids), and/or an epidural blood patch [1,2].

^B Presented at the SAEM annual meeting in Boston, MA, May 2003.

^BB The authors thank Dr Brian Robinson for his participation in this trial.

0735-6757/$ - see front matter D 2005