Pocket Oncology (Pocket Notebook Series), 1st Ed.

MALIGNANT BOWEL OBSTRUCTION & TPN

Reggie T. Saldivar and Roma Tickoo

Definition

• Any process, mechanical or functional, preventing the forward propulsion of bowel contents

• Can be partial or complete, single or multifocal & is a medical emergency

Risk Factors and Prevalence

• Common complication in pts w/abdominal or pelvic CAs

• Frequency as high as 42% of advanced ovarian CAs

• Small bowel > large bowel involvement

Clinical Manifestations

• Nausea, vomiting, abdominal pain, ± abdominal distention, hiccups

• Absent bowel sounds, hypoactive or high-pitched → impending obstruction

• Vomiting occurs early in proximal obstructions, late in distal

• Abdominal pain may be continuous (90%), colicky (75%)

Diagnosis

• Hx Æ prior abd surgery or malignancy must be sought

• PEx → fever, tachycardia, abd distention, paucity of bowel sounds, surgical abd scars. Rectal exam may reveal empty vault, mass or blood PR

• Imaging → dilated loops of bowel, air–fluid levels, transition point on CT

Management

Hydration

• Most pts w/bowel obstruction are dehydrated → ↑ secretion of water into bowel ↓ PO of fluids

• No correlation between intensity of thirst, dry mouth, & quantity of hydration administered (J Palliat Care 1998;9:298)

• Sx of dry mouth can be addressed w/sips of water, ice chips, & meticulous oral care(J Pain Symptom Manage 2000;19:23)

• Indications for hydration in terminally ill CA pts:

Prevent dehydration-induced agitation/confusion

Prev of prerenal failure w/resulting delirium, myoclonus, & seizures

• Limit PO to volume of UOP/24 h + 500 mL for insensible losses

Total Parental Nutrition

• Avoid routine use of TPN - controversial use in advanced incurable CA pts (Nutrition 1996;12:163)

• Selection of appropriate pts the most critical decision

• Will not correct CA-induced cachexia

• <50% of terminally ill CA pts experience sensation of hunger or thirst. Select pts at end of life – sips of water, soup, or ice chips may be offered for pleasure if tolerated.

• Nutritional benefits limited if delivered only for very short time

• Requires full discussion w/pt & family regarding risks, benefits, & triggers for discontinuation of TPN