Intestinal Ascariasis

Author: Santip Srisuwan, M.D.

Axial CT image shows multiple tubular filling defects (arrows) within the opacified lumen of the small bowel. Note contrast filling within the filling defects.

Facts:

• Most common helminthic infection (worldwide prevalence 25%)
• Usually asymptomatic.
• Possible symptoms are colicky abdominal pain in adults and growth retardation/intussusception/volvulus in children

Imaging

• X-ray: usually normal but may present as bowel obstruction (partial or complete), or soft tissue masses
• US: hypo echoic curvilinear tubular structures with well-defined echogenic walls and curling movement of the worm during the exam
• CT: long, thin tubular structure coiled within the small bowel, outlined by oral contrast materials

References:

1. Hommeyer SC, Hamill GS, Johnson JA. CT diagnosis of intestinal ascariosis. Abdom Imaging 1995;20:315-316.

2. Rodrigues EJ, Gama MA, Ornstein SM, et al. Ascariasis causing small bowel volvulus. Radiographics 2003;23:1291-3.

3. Villamizar E, Mendez M, Bonilla E, et al. Ascaris lumbricoides infestation as a cause of intestinal obstruction in children: experience with 87 cases. J Pediatr Surg 1996;3:201-4.

4. Hendi JM, Horton KM, Fishman EK. Ascariasis infection of the colon: MDCT evaluation. Emerg Radiol 2006;12:180-1.

5. Bude RO, Bowerman RA. Case 20: Biliary ascariasis. Radiology 2000;214:844-7.

6. Hershkovitz D, Wasserberg N. Large bowel obstruction due to Ascaris lumbricoides. IMAJ 2004;6:115-116.

Triquetral Fracture

A lateral wrist radiograph shows a small bone fragment (arrow) dorsum to the wrist with overlying soft tissue swelling.

Facts:

• Second most common carpal bone fracture
• Two main types: dorsal chip fracture and body fracture
• Dorsal chip fracture (like in our case ) believed to be due to forceful impingement of the triquetrum during wrist hyperextension
• Body fracture frequently associated with perilunate dislocation (direct blow)
• Pain and swelling localized at the dorsum of the wrist where triquetrum is located
• Complication: motor branch of ulnar nerve injury

Imaging

• Chip fracture best seen on lateral radiograph with hand in flexion
• Body fracture best seen on AP and oblique radiographs
• Fractures are possibly underreported. CT can help in suspected cases.

Reference:

Simon RR, Koenigsknecht SJ. Emergency orthopedics: the extremities, 2001.

Pneumothorax on Ultrasound

M-mode ultrasound images of the lungs (right and left) show a normal "lung sliding" on the right side "Right" and absence of it on the left side "Left".

Facts:

• Ultrasound can be performed to diagnose pneumothorax with high accuracy
• Normal "lung sliding" is seen when pleura moves against the chest wall during respiration. The movement is easily seen on real-time imaging and can be captured on M-mode ultrasound
• M-mode US shows normal lung sliding as a "seashore sign", in which the motion of pleura/lung produces sand-like granular appearance on the image. The non-mobile chest wall shows several uninterrupted band or "sea"
• Some diseases may produce "loss of lung sliding", most notably pneumothorax

Pneumothorax on US

• Absence of lung sliding shown on real-time imaging
• On M-mode as "barcode sign" or "stratosphere sign" (see above image labeled "left")
• More specific sign is the "lung point sign"

Our case: left pneumothorax (confirmed with radiography)

Reference:

Lichtenstein DA, Menu Y. A bedside ultrasound sign ruling out pneumothorax in the critically ill. Chest 1995; 108:1345-48.