13.3 Lifespan Gastrointestinal Care

The FNP-BC secondary classifications include eight age groups from infant to frail elderly. Gastrointestinal items will not always announce the age in the first clause, but the developmental and obstetric frame changes the diagnosis. This section is lifespan application of the syndromes in 13.1 and the drugs in 13.2.

Infants: GER versus GERD, and the surgical vomiting emergencies

Gastroesophageal reflux (GER) is effortless spitting in an otherwise thriving infant — the “happy spitter.” Growth is normal, the child is not in pain, and the exam is benign. Teaching is upright holding after feeds, smaller more frequent feeds if overfeeding is the story, and reassurance. You do not start a PPI on every bib.

GERD is reflux with complications: poor weight gain, marked feeding refusal, back-arching that looks like Sandifer, hematemesis, or recurrent respiratory disease. Those infants need a growth chart, a feeding assessment (including oversupply, latch, and cow-milk protein), and a lower threshold for pediatric GI. Acid suppression is not the first move in an uncomplicated happy spitter and is used more carefully in infants than in adults because benefit is modest and risk is real.

Hypertrophic pyloric stenosis presents at 2–8 weeks (classically a first-born boy, but do not require that stereotype) with progressive nonbilious projectile vomiting, persistent hunger, and weight loss or dehydration. A palpable olive in the right upper quadrant is classic when present; ultrasound is the diagnostic test. Labs may show hypochloremic, hypokalemic metabolic alkalosis. This is surgical (pyloromyotomy after fluid and electrolyte repair), not a formula rotation in clinic.

Intussusception is the other infant/toddler surgical emergency you must not miss. Peak is often 6–36 months. The child has intermittent colicky pain, draws up the legs, may look well between waves, then becomes lethargic. Currant-jelly stool is late. A sausage-shaped mass may be felt. Destination is the ED for ultrasound and air or contrast enema (diagnostic and often therapeutic), with surgery if reduction fails or peritonitis is present. Do not send that child home on an H2RA.

Cow’s-milk protein allergy (or food-protein-induced proctocolitis) classically shows blood-streaked stools in a well-appearing, often breastfed or formula-fed young infant, sometimes with eczema or marked fussiness. First FNP move in a well infant is a time-limited maternal dairy (and often soy) elimination if breastfeeding, or a switch to an extensively hydrolyzed formula — not an adult elimination diet of 20 foods, and not a colonoscopy. Blood that comes with sick appearance, bilious vomiting, or abdominal distention is not CMPA until surgical and infectious causes are gone.

Constipation commonly starts with formula changes or complementary solids. Hard, pellet stools, straining, and blood from an anal fissure are typical. Treat with juice that contains sorbitol in older infants when appropriate, extra water if solids have started, and PEG when diet fails — after you have excluded Hirschsprung red flags (failure to pass meconium in the first 48 hours, ribbon stools, explosive stools on rectal exam, failure to thrive).

Biliary atresia is a time-critical infant liver emergency. Persistent jaundice after 2 weeks of age, pale (acholic) stools, dark urine, and a conjugated hyperbilirubinemia need same-week pediatric GI, not “watch the breast-milk jaundice another month.” Kasai portoenterostomy success falls as weeks pass. Any infant with pale stools is a same-day call, not a next-well-visit item.

School-age: functional pain, celiac, constipation, encopresis

Most recurrent abdominal pain in a well-grown school-age child with a normal exam is functional abdominal pain or constipation. Rome-style pediatric criteria still want positive features (pain related to stool, school stress, peri-umbilical location) and a limited workup, not a CT on every Friday afternoon. Red flags that break the functional label: involuntary weight loss, linear-growth failure, nocturnal diarrhea or pain that wakes the child, blood, fever, oral ulcers, arthritis, delayed puberty, perianal disease, or a strong IBD family history.

Celiac disease often presents in this age group as iron-deficiency anemia, bloating, poor growth, constipation or diarrhea, or dermatitis herpetiformis. Test with tTG-IgA plus total IgA while the child still eats gluten (Section 13.1). Do not start a gluten-free diet “for two weeks to see” before serology — you will scramble the diagnosis for a year.

Constipation is the most common “organic-adjacent” cause of school-age pain, stool withholding, and urinary accidents. Encopresis is overflow soiling around a rectal mass; families hear “diarrhea” and feel blamed. Examine the abdomen and, when appropriate, the rectal vault; explain the physiology without shame; disimpact if needed; then use daily PEG long enough for the stretched rectum to recover (often months, not three days), scheduled toilet sits after meals, and a reward plan. Stimulant rescue is for the packed week, not the only plan.

Pregnancy: nausea, reflux, and intrahepatic cholestasis

Nausea and vomiting of pregnancy (NVP) is common in the first trimester, peaks around weeks 9–11, and should not cause marked weight loss or ketonuria. First-line pharmacologic therapy after diet and ginger is doxylamine–pyridoxine. Hyperemesis gravidarum is the severe end: weight loss, dehydration, ketonuria, and inability to keep fluids down. That is obstetric/ED care for IV fluids, thiamine, and antiemetics — not another peppermint-tea handout.

GER worsens in pregnancy because progesterone relaxes the lower esophageal sphincter and the gravid uterus raises pressure. Start with meals, head-of-bed elevation, and antacids; add an H2RA; use a PPI when symptoms stay significant. Avoid sodium bicarbonate antacids that deliver a large sodium load.

Intrahepatic cholestasis of pregnancy (ICP) is an obstetric emergency of timing, not a dermatology curiosity. The clue is intense pruritus, especially on the palms and soles, often without a primary rash, in the second or third trimester. Order serum bile acids (and LFTs). Elevated bile acids plus that itch picture means urgent obstetric referral the same day you have the result — ICP raises the risk of stillbirth and changes delivery timing. Do not treat it as stretch-mark itch or as “just GERD at night.” Ursodeoxycholic acid and delivery planning belong to obstetrics; the FNP’s job is recognition and same-day handoff.

Older and frail adults: cancer screening, ischemia, impaction, C. difficile

Colorectal cancer screening is a Domain I/III item that lives in the GI lifespan chapter because the age cutoffs are tested. For average-risk adults, USPSTF rates screening Grade A from ages 50–75, Grade B from 45–49, and Grade C from 76–85 (individualize by prior screening and comorbidity). Offer a stool-based test or a structural exam; a positive stool test is a colonoscopy, not a repeat FIT next year. High-risk people (first-degree relative with CRC or advanced adenoma, IBD colitis, hereditary syndromes) leave the average-risk schedule and need GI-directed intervals. Do not tell a healthy 46-year-old that screening “starts at 50.” Do not force a frail 84-year-old with a recent normal colonoscopy into another prep without a goals-of-care talk (Grade C).

Mesenteric ischemia is the older-adult abdominal catastrophe. Pain out of proportion to the exam, often in a patient with atrial fibrillation, heart failure, or atherosclerotic disease, is ED/vascular, not an office dicyclomine trial. Lactate can rise late; a soft abdomen does not exclude dead bowel. Post-prandial “abdominal angina” with sitophobia and weight loss is the chronic form and still needs urgent vascular/GI evaluation, not another PPI.

Fecal impaction presents as overflow liquid stool, urinary retention, delirium, or anorexia in a frail or opioid-treated adult. Digital exam makes the diagnosis. Disimpact (manual, then enemas, then a PEG cleanout) and rebuild a bowel regimen. Loperamide for “diarrhea” in a nursing-home resident is a classic harm.

Clostridioides difficile follows antibiotics (and sometimes chemotherapy or hospitalization). Watery diarrhea, cramping, leukocytosis, and recent beta-lactams, clindamycin, or fluoroquinolones should trigger stool testing. Stop the inciting antibiotic if you can. Current adult first-line therapy is oral vancomycin or fidaxomicin, not metronidazole as the default. Do not give loperamide. Infection-control counseling (hand washing with soap — spores laugh at alcohol foam) is part of the prescription. Recurrent C. diff needs GI/ID pathways (tapered vancomycin, fidaxomicin, bezlotoxumab, or fecal microbiota therapy), not a third azithromycin for “another stomach bug.”

Other older-adult GI traps: ischemic colitis after a hypotensive episode (left-sided pain and bloody stool — ED), diverticulitis (Section 13.1), medication-induced constipation (opioids, anticholinergics, iron, calcium), and upper GI bleeding from NSAID ulcers. The frail elderly have less reserve; the same Benson “wait and see” interval you use in a 25-year-old is too long when vital signs are borderline.

FNP vignette trap: a 6-week-old with projectile nonbilious vomiting is pyloric stenosis, not GER. A 10-month-old with intermittent screaming and currant-jelly stool is intussusception, not viral gastroenteritis. A 34-week pregnant patient with palmar itch and a bile-acid of 42 µmol/L is ICP, not eczema. An 81-year-old with AF and pain out of proportion is mesenteric ischemia, not constipation from the nursing-home diet.