# Clinical Cases: Gastrointestinal Disorders

## Case 1: Intussusception

### Patient Demographics
- **Age:** 9-month-old male
- **Sex:** Male

### Chief Complaint
"He's screaming in pain and has bloody stool."

### History of Present Illness
A 9-month-old previously healthy male presents with episodes of severe crying and drawing up of legs that started 8 hours ago. Parents describe the episodes as sudden onset, with the infant screaming inconsolably for 2-3 minutes, then becoming quiet and appearing tired. The episodes occur approximately every 15-20 minutes. He had one episode of non-bilious vomiting. Between episodes, he has been increasingly lethargic and less interested in feeding. Mother noticed a bowel movement 2 hours ago that looked like "red jelly" mixed with mucus. He had a viral illness with mild diarrhea one week ago that resolved. No fever. This is the first time he has had these symptoms.

### Growth Parameters
- **Weight:** 9.0 kg (55th percentile)
- **Length:** 71 cm (50th percentile)
- **Head circumference:** 45 cm (50th percentile)

### Physical Examination
- **General:** Pale, lethargic between episodes; during episode: inconsolable crying, legs drawn up
- **Vital signs:** T 37.2C, HR 145, RR 32, BP 90/55
- **HEENT:** Mucous membranes moist, no oral lesions
- **Cardiovascular:** Tachycardia, no murmur
- **Abdomen:**
  - Soft between episodes
  - Palpable sausage-shaped mass in right upper quadrant
  - Right lower quadrant feels "empty" (Dance sign)
  - Mild distension
  - No peritoneal signs
- **Rectal:** "Currant jelly" stool - bloody mucus on examiner's finger
- **Skin:** Pale, delayed capillary refill (3 seconds)
- **Neurologic:** Lethargic, but arousable

### Workup
- **Abdominal X-ray:** Paucity of gas in right lower quadrant, soft tissue mass in right upper quadrant, no free air
- **Abdominal ultrasound:** "Target sign" - concentric rings representing bowel-within-bowel in right abdomen; no free fluid
- **CBC:** WBC 14,000, Hgb 11.2, Platelets 320,000
- **CMP:** Na 138, K 4.5, BUN 18 (mild dehydration), Cr 0.3

### Diagnosis
**Ileocolic intussusception**

### Clinical Reasoning
The classic triad of colicky abdominal pain (paroxysmal crying with legs drawn up), "currant jelly" stool (blood and mucus), and palpable abdominal mass (sausage-shaped) in a child 6-36 months is pathognomonic for intussusception. The preceding viral illness is a common antecedent, thought to cause lymphoid hyperplasia serving as a lead point. The lethargy between episodes is a concerning sign of progression. Ultrasound confirmation with the "target sign" is diagnostic and preferred over barium enema for initial imaging.

### Management
1. **NPO and IV access:** Normal saline bolus 20 mL/kg for resuscitation
2. **Pediatric surgery consultation** (obtain early)
3. **Air enema reduction (therapeutic):**
   - Gold standard for uncomplicated intussusception
   - Performed under fluoroscopy by pediatric radiologist
   - Success rate 80-90% on first attempt
   - Contraindications: peritonitis, perforation, shock
4. **If air enema unsuccessful:**
   - Second attempt can be considered after 30-60 minutes
   - Maximum 3 attempts
5. **Surgical intervention** indicated for:
   - Failed enema reduction
   - Perforation or peritonitis
   - Hemodynamic instability
   - Pathologic lead point suspected (Meckel's, polyp, lymphoma)
6. **Post-reduction:**
   - Observe 12-24 hours for recurrence
   - Resume feeds when tolerating clear liquids
   - Recurrence rate 5-10% (higher with multiple reductions)
7. **Discharge instructions:**
   - Return for recurrent symptoms (recurrence most common within 72 hours)

### Clinical Image
![Intussusception ultrasound target sign](case_01_image.jpg)

**Image Description:** Ultrasound image demonstrating the "target sign" of intussusception - concentric rings representing the telescoped bowel-within-bowel.

**Source:** Radiopaedia
**URL:** https://radiopaedia.org/cases/intussusception-target-sign
**License:** CC BY-NC-SA 3.0

---

## Case 2: Pyloric Stenosis

### Patient Demographics
- **Age:** 5-week-old male
- **Sex:** Male

### Chief Complaint
"My baby vomits after every feed and isn't gaining weight."

### History of Present Illness
A 5-week-old first-born male presents with progressive non-bilious vomiting that started 1 week ago and has worsened over the past few days. Initially, he spit up small amounts after feeds, but now he vomits "everything he eats" - parents describe the vomiting as "shooting across the room" (projectile). The vomiting occurs 15-30 minutes after feeds. He is bottle-fed with standard formula and appears hungry immediately after vomiting, eagerly trying to feed again. Parents note decreased wet diapers (3 per day, down from 6-8). Last bowel movement was 2 days ago. Birth weight was 3.4 kg at term; he gained appropriately until 2 weeks ago. Family history notable for father who had "stomach surgery" as an infant.

### Growth Parameters
- **Birth weight:** 3.4 kg (50th percentile)
- **Current weight:** 3.6 kg (10th percentile - below expected)
- **Length:** 53 cm (35th percentile)
- **Expected weight at 5 weeks:** ~4.3 kg

### Physical Examination
- **General:** Alert, hungry-appearing infant, thin with visible rib outlines
- **Vital signs:** T 36.8C, HR 165, RR 40, BP 75/50
- **HEENT:** Sunken anterior fontanelle, dry mucous membranes, sunken eyes
- **Cardiovascular:** Tachycardia
- **Abdomen:**
  - Scaphoid
  - Visible gastric peristaltic waves moving left to right (seen during feeding)
  - Firm, mobile, olive-shaped mass palpable in right upper quadrant/epigastrium (palpable pylorus)
  - No distension
- **Skin:** Decreased skin turgor, dry
- **Neurologic:** Alert, good suck

### Workup
- **Abdominal ultrasound:**
  - Pyloric muscle thickness: 5 mm (abnormal >3 mm)
  - Pyloric channel length: 18 mm (abnormal >14 mm)
  - Target sign with elongated pyloric channel
- **Basic metabolic panel:**
  - Na 133 mEq/L (low)
  - K 3.0 mEq/L (low)
  - Cl 88 mEq/L (low)
  - HCO3 32 mEq/L (elevated)
  - BUN 28 mg/dL (elevated)
  - Cr 0.5 mg/dL
- **Blood gas:** pH 7.52, pCO2 48, HCO3 34 (hypochloremic, hypokalemic metabolic alkalosis with respiratory compensation)

### Diagnosis
**Hypertrophic pyloric stenosis with dehydration and hypochloremic, hypokalemic metabolic alkalosis**

### Clinical Reasoning
The classic presentation of pyloric stenosis includes: first-born male, age 3-6 weeks, progressive non-bilious projectile vomiting, hungry after vomiting, palpable "olive" mass, visible peristaltic waves, and failure to thrive. The metabolic abnormalities result from loss of gastric HCl in vomitus - the kidney retains H+ in exchange for K+, leading to the classic "paradoxical aciduria" and the characteristic hypochloremic, hypokalemic metabolic alkalosis. Ultrasound criteria (muscle >3 mm, length >14 mm) confirm the diagnosis.

### Management
1. **NPO and IV fluids:**
   - Initial: NS 20 mL/kg bolus
   - Maintenance: D5 + 0.45% NS with 20 mEq/L KCl at 1.5x maintenance
2. **Correct electrolyte abnormalities:**
   - Goal: Cl >100 mEq/L, K >3.5 mEq/L, HCO3 <26 mEq/L before surgery
   - May take 24-48 hours of fluid resuscitation
3. **Surgical consultation:**
   - Pyloromyotomy (Ramstedt procedure) - definitive treatment
   - Laparoscopic or open approach
   - Surgery is NOT emergent - stabilize patient first
4. **Preoperative management:**
   - NGT only if persistently vomiting
   - Serial electrolytes every 6-12 hours
5. **Postoperative:**
   - Resume feeds 4-6 hours after surgery
   - Advance as tolerated
   - Some postoperative emesis is common and self-limited
6. **Prognosis:** Excellent, cure rate essentially 100%

### Clinical Image
![Pyloric stenosis ultrasound](case_02_image.jpg)

**Image Description:** Ultrasound image demonstrating hypertrophic pyloric stenosis with elongated, thickened pyloric muscle and the characteristic "target sign."

**Source:** Radiopaedia
**URL:** https://radiopaedia.org/cases/pyloric-stenosis-ultrasound
**License:** CC BY-NC-SA 3.0

---

## Case 3: Celiac Disease

### Patient Demographics
- **Age:** 4-year-old female
- **Sex:** Female

### Chief Complaint
"She has chronic diarrhea and isn't growing well."

### History of Present Illness
A 4-year-old female is brought in by her parents due to concerns about poor weight gain and chronic loose stools over the past 18 months. She has 3-5 loose, pale, foul-smelling, bulky stools daily. She was doing well until around age 2.5 when parents noticed her belly became more "bloated" and stools changed. She has poor appetite and is described as "picky" but eats bread, pasta, and crackers. She often complains of "tummy aches." Growth records show she has fallen from the 50th percentile for weight at age 2 to the 10th percentile now. She is irritable and fatigues easily. No blood in stools, no vomiting, no fever. Family history includes a maternal aunt with "gluten intolerance" and grandmother with thyroid disease.

### Growth Parameters
- **Weight:** 13.5 kg (10th percentile, previously 50th)
- **Height:** 97 cm (15th percentile, previously 40th)
- **BMI:** 14.3 kg/m2 (8th percentile)
- **Previous weight at age 2:** 12 kg (50th percentile)

### Physical Examination
- **General:** Thin girl with prominent abdomen, appears pale and tired
- **Vital signs:** Normal
- **HEENT:** Pale conjunctivae, angular cheilitis, dental enamel defects
- **Cardiovascular:** Normal
- **Respiratory:** Normal
- **Abdomen:** Distended, tympanic, non-tender, no organomegaly
- **Musculoskeletal:** Decreased muscle mass, especially gluteal wasting
- **Skin:** Dry, no rash
- **Neurologic:** Mildly irritable, appropriate for age

### Workup
- **CBC:** Hgb 9.8 g/dL, MCV 72 fL (microcytic anemia), WBC and platelets normal
- **Iron studies:** Ferritin 8 ng/mL (low), TIBC elevated (iron deficiency)
- **CMP:** Albumin 3.2 g/dL (low), otherwise normal
- **Tissue transglutaminase IgA (tTG-IgA):** 185 U/mL (normal <20, strongly positive)
- **Total IgA:** 95 mg/dL (normal - rules out IgA deficiency)
- **Endomysial antibody (EMA):** Positive
- **Stool studies:** Fat malabsorption (increased fecal fat)
- **Upper endoscopy with duodenal biopsy:**
  - Villous atrophy
  - Crypt hyperplasia
  - Increased intraepithelial lymphocytes
  - Marsh classification: Stage 3b

### Diagnosis
**Celiac disease with malabsorption, iron deficiency anemia, and failure to thrive**

### Clinical Reasoning
This child presents with classic celiac disease: chronic diarrhea with steatorrhea (pale, foul-smelling, bulky stools), abdominal distension, failure to thrive, irritability, and iron deficiency anemia. The onset after gluten introduction (typically after age 2 when dietary gluten increases) and positive family history support the diagnosis. The strongly positive tTG-IgA with positive EMA and characteristic duodenal biopsy (villous atrophy, crypt hyperplasia, increased IELs) confirm the diagnosis. The normal total IgA rules out IgA deficiency, which would cause false-negative serologies.

### Management
1. **Strict lifelong gluten-free diet:**
   - Eliminate wheat, barley, rye
   - Oats are controversial (may be contaminated; pure oats tolerated by most)
   - Read all food labels
   - Avoid cross-contamination
2. **Nutritional supplementation:**
   - Iron supplementation until anemia resolves
   - Vitamin D and calcium (assess bone density if deficient)
   - Multivitamin with B vitamins
3. **Referral to registered dietitian** experienced in celiac disease
4. **Family education:**
   - Celiac support groups
   - Gluten-free living resources
5. **Screen first-degree relatives:** tTG-IgA (10% risk)
6. **Associated condition screening:**
   - Thyroid function (TSH)
   - Type 1 diabetes screening if symptoms
7. **Monitoring:**
   - Repeat tTG-IgA in 6-12 months (should decrease with compliance)
   - Monitor growth, symptoms, nutritional status
   - Repeat endoscopy generally not needed if clinical/serologic response
8. **Pneumococcal vaccine** (functional hyposplenism in celiac)

### Clinical Image
![Duodenal biopsy celiac disease](case_03_image.jpg)

**Image Description:** Duodenal biopsy histopathology demonstrating villous atrophy, crypt hyperplasia, and increased intraepithelial lymphocytes characteristic of celiac disease.

**Source:** Wikimedia Commons
**URL:** https://commons.wikimedia.org/wiki/File:Celiac_Disease.jpg
**License:** CC BY-SA 3.0