Correspondence

A Medical Mystery: Dilated Bowel — The Answer

N Engl J Med 2007; 356:1381-1382March 29, 2007

Article

The medical mystery in the February 1 issue1 involved a 70-year-old man who presented with a history of increasing abdominal distention. The patient was evaluated by means of computed tomography (CT) after an abdominal radiograph raised concern about a sigmoid volvulus. The diagnosis of a colonic pseudo-obstruction was made after the CT scan and a follow-up contrast enema study showed dilated loops of colon extending to the rectum, without evidence of blockage or perforation. An underlying parasitic infection was ruled out by means of additional laboratory testing.

The CT scout image, however, provided a clue to the patient's disease. With the patient lying still on a CT-scanner table, the scout image was acquired on a 64-detector–row CT scanner. The scout image was used to preview the area of interest for subsequent CT imaging. It revealed an unusual sinusoidal artifact involving the patient's right forearm (Figure 1AFigure 1Parkinson's Disease in a 70-Year-Old Man.). The patient's concurrent electrocardiogram (Figure 1B) showed an analogous artifact, mimicking an atrioventricular block. This rhythm is in fact a normal sinus rhythm with superimposed, sharp pseudoflutter waves (Figure 1B) that are not associated with the QRS complex.

This case shows several features of a Parkinsonian tremor, while highlighting the association between Parkinson's disease and a colonic pseudo-obstruction. The tremor is present at rest and is often confined to one limb. Besides the classic “pill-rolling” tremor, pronation–supination of the hand and forearm, as seen in this patient, is a common presentation. The frequency of the tremor is typically between 3 and 5 cycles per second. In this case, on the basis of a CT scout table velocity of 79 mm per second and an electrocardiographic sweep speed of 25 mm per second, the tremor frequency was estimated to be 3 and 4 Hz by means of CT and electrocardiography, respectively — findings ultimately confirmed by direct visual observation.

Jason Handwerker, M.D.
Vassilios D. Raptopoulos, M.D.
Beth Israel Deaconess Medical Center, Boston, MA 02215
jhandwer@bidmc.harvard.edu

1 References