Pyloric Stenosis Flashcards
1
Q
Pathology
A
- obstruction in first part of duodenum
- fibrotic scarring–> compensated by dilation and hypertrophy of stomach muscle–> failure of compensation
2
Q
Clinical feature
A
- characteristic profuse vomiting (free from bile)
- vomitus may contain food eaten 1-2 days previously and smells faeculent
- loss of weight
- constipation
- weakness (electrolyte disturbance)
3
Q
Physical examination
A
- dehydrated and wasted
- gastric splash (succussion splash): shaking patient’s abdomen several hours after meal
- visible peristalsis
- grossly dilated, hypertrophied stomach, full of stale food and fluid (palpated)
- gastric aspiration: morning resting juice of over 100 ml
4
Q
Special investigation
A
- gastroscopy: following decompression of stomach with nasogastric tube
- CT scan
- ABG and electrolyte estimation: hypochloraemic alkalosis with hypokalaemia and uraemia
5
Q
Biochemical disturbance
A
- copious vomiting–> dehydration from fluid loss and alkalosis due to loss of hydrogen ions from stomach–> compensated by renal excretion of sodium bicarbonate
- dehydration–> diminished volume and increased concentration of urine–> chloride content disappears (pH alkaline)
- vomiting continues–> large sodium deficit–> hydrogen ion and potassium ion are substituted for sodium–> paradox–> excrete acid urine
- blood urea rise (partly due to dehydration, partly due to renal impairment secondary to electrolyte disturbance)–> tetany (shift of ionized, weakly alkaline calcium phosphate to its unionized state)–> concentration of plasma calcium ions fall (total calcium concentration is not affected)
6
Q
Treatment
A
- intravenous replacement of saline together with potassium
- daily gastric lavage: remove debris from stomach, restore function of stomach, allow fluid reabsorption to take place by mouth
- vitamin C: patient with chronic duodenal ulcer often deficient in ascorbic acid
- antrectomy with Roux-en-Y gastroenterostomy
