14. Hypertrophic Pyloric Stenosis. pptx

For study purpose

1. Hypertrophic Pyloric Stenosis Presenter- Zubeir Omar Resident Supervisor- Dr Helena Machibya Radiologist Date- 05/01/2024

2. Outline Introduction Imaging Modalities Differentials References

3. Introduction Idiopathic thickening of the gastric pyloric musculature resulting in gastric outlet obstruction. M: F = 4.7 : 1 ( Chalya , Manyama et. al) Prevalence of   2-5 per 1,000 births Mean age 6- 12 weeks, may occur from 3 weeks c/c- non bilous projectile vomiting - signs of dehydration - peristaltic wave on inspection - palpable olive sized mass in RUQ Risk factors- family history - 1 st born in the family - Bottle feeding - Cesarian delivery

4. Pyloric canal-<15mm Muscle thickness-<3mm

5. Imaging modalities Plain Xray Ultrasound Fluoroscopy

6. Abdominal x-ray findings are non-specific but may show a distended stomach with minimal distal intestinal bowel gas T he stomach appears distended, air-filled and with wave-like contours, resembling the appearance of a caterpillar  This sign is produced when the gastric hyperperistaltic waves come to an abrupt stop at the pylorus 

7. Plain Xray Catepillar sign

8. Ultrasound Diagnostic precision of approximately 100% Imaging modality of choice Easy ultrasound technique is to find gallbladder then turn the probe obliquely sagittal to the body in an attempt to find the pylorus longitudinally . Pyloric muscle thickness > 3 mm Pyloric transverse diameter > 14 mm Longitudinal measurement> 15 mm 3.1415

9. Described sonographic signs include : Antral nipple sign Cervix sign Target sign retrograde peristalsis  exaggerated peristaltic waves 

10. Sonographic Signs Antral nipple sign- redundant pyloric mucosa protruding into the gastric antrum 

11. Cervix sign- indentation of pylorus in fluid filled antrum

12. Target sign- hypertrophied hypoechoic muscle surrounding echogenic mucosa

13. FLOUROSCOPY An upper gastrointestinal series (barium meal) excludes other, more serious causes of pathology, but the findings of an upper gastrointestinal series infer, rather than directly visualize, the hypertrophied muscle

14. On upper gastrointestinal fluoroscopy: D elayed gastric emptying P eristaltic waves (caterpillar sign)   E longated  pylorus with a narrow lumen (string sign) which may appear duplicated due to puckering of the mucosa (double track sign) T he pylorus indents the contrast-filled antrum (shoulder sign) and (tit sign)  or base of the duodenal bulb (mushroom sign) T he entrance to the pylorus may be beak-shaped (beak sign)

15. Fluoroscopy String Sign

16. Double track sign Beak sign

17. Tit sign

18. Differentials There is usually little differential when imaging findings are appropriate. Clinically it is important to consider other causes of vomiting in infancy. A degree of  pylorospasm is common in infancy and is responsible for some delay in gastric emptying. The pylorus, however, appears sonographically normal. Gastro-esophageal reflux which represents the cause of vomiting in two-thirds of infants referred to radiology  Other causes of proximal gastrointestinal obstruction can be considered Midgut volvulus Gastric antral web Duodenal web/stenosis Annular pancreas Bezoar

19. References Radiopedia Fundamentals of diagnostic radiology Grainger & Allison’s Ultrasoundpedia.com Researchgate.net Slideshare.net Pubs.rsna.org