Gastrointestinal · Year 2 · from Gastrointestinal

Case 1: Celiac Disease with Malabsorption

Patient Presentation

Demographics: 32-year-old female

Chief Complaint: Chronic diarrhea, bloating, and fatigue for 18 months

History of Present Illness: The patient has experienced progressive symptoms over 18 months including 4-6 loose, foul-smelling, greasy stools daily that are pale and float in the toilet bowl. She has significant bloating and abdominal discomfort, particularly after eating bread and pasta. She has lost 18 pounds unintentionally despite maintaining her usual diet. She reports profound fatigue, difficulty concentrating, and an intensely itchy rash on her elbows and knees that comes and goes.

Past Medical History: Iron deficiency anemia (treated with oral iron with minimal response), hypothyroidism (on levothyroxine), first-degree relative (mother) with celiac disease

Social History: Non-smoker, rare alcohol use

Physical Examination

  • Vital Signs: Normal
  • General: Thin female appearing fatigued
  • Skin: Grouped vesicular lesions with excoriations on extensor surfaces of elbows and knees bilaterally (dermatitis herpetiformis)
  • Mouth: Angular cheilosis, glossitis with smooth tongue
  • Abdomen: Soft, mild diffuse tenderness, hyperactive bowel sounds, no organomegaly
  • Extremities: Mild pitting ankle edema

Workup and Results

  • CBC: Hemoglobin 9.8 g/dL, MCV 76 fL (microcytic), Platelets 420,000
  • Iron Studies: Ferritin 8 ng/mL (low), Serum iron 25 mcg/dL (low), TIBC 450 mcg/dL (elevated), Transferrin saturation 6% (low)
  • Vitamin Levels: Vitamin D 8 ng/mL (severely deficient), Folate low-normal, B12 normal
  • CMP: Albumin 3.0 g/dL (low), Calcium 8.0 mg/dL (low)
  • Celiac Serology:
  • Total IgA: Normal (rules out IgA deficiency that would cause false-negative)
  • Tissue Transglutaminase IgA (tTG-IgA): 145 U/mL (normal < 4; markedly elevated)
  • Anti-endomysial antibody (EMA): Positive
  • DEXA Scan: T-score -2.8 at lumbar spine (osteoporosis)
  • Upper Endoscopy with Duodenal Biopsies: Scalloped, fissured duodenal folds with loss of normal villi; histology shows villous atrophy, crypt hyperplasia, and increased intraepithelial lymphocytes (> 40 per 100 enterocytes) - Marsh IIIb

Endoscopic image of the duodenum in celiac disease showing characteristic findings: scalloped duodenal folds with fissures and loss of normal villous pattern (mosaic pattern). These endoscopic changes correlate with villous atrophy seen on histology.

Image Source: Wikimedia Commons. Samir, CC BY-SA 3.0

Diagnosis

Celiac Disease (Gluten-Sensitive Enteropathy) with:

  • Malabsorption (steatorrhea, weight loss)
  • Iron-refractory iron deficiency anemia
  • Vitamin D deficiency with osteoporosis
  • Dermatitis herpetiformis

Clinical Correlation

Celiac disease is an autoimmune enteropathy triggered by gluten (from wheat, barley, rye) in genetically susceptible individuals (HLA-DQ2 or HLA-DQ8 positive). Key teaching points:

Pathophysiology:

  • Gluten peptides (specifically gliadin) cross the intestinal epithelium
  • Tissue transglutaminase (tTG) deamidates gliadin, creating neoantigens
  • These are presented to T cells by HLA-DQ2/DQ8, triggering an immune response
  • Results in mucosal inflammation, villous atrophy, and malabsorption

Why This Patient Has Specific Deficiencies:

  • Iron deficiency (refractory to oral iron): Iron is absorbed in the duodenum - the most affected region in celiac disease
  • Vitamin D deficiency: Fat-soluble vitamin malabsorption due to impaired fat absorption
  • Osteoporosis at young age: Calcium and vitamin D malabsorption
  • Steatorrhea: Mucosal damage impairs fat absorption (fat malabsorption occurs early)

Dermatitis Herpetiformis:

  • Cutaneous manifestation of celiac disease (present in ~15-25% of celiac patients)
  • IgA deposits in dermal papillae cause intensely pruritic vesicular lesions
  • Classic distribution: extensor surfaces (elbows, knees), buttocks, scalp
  • Responds to gluten-free diet and dapsone

Diagnostic Approach:

  1. Serologic testing while patient is consuming gluten (tTG-IgA is 95% sensitive and specific)
  2. Check total IgA to exclude IgA deficiency (causes false negatives)
  3. Confirm with duodenal biopsy showing Marsh classification changes
  4. Clinical and histologic response to gluten-free diet confirms diagnosis

Treatment

  • Strict lifelong gluten-free diet - eliminate all wheat, barley, rye; oats are usually tolerated but must be certified gluten-free (cross-contamination risk)
  • Nutritional supplementation:
  • Iron supplementation (may need IV iron initially given malabsorption)
  • Vitamin D3 50,000 IU weekly until replete, then maintenance
  • Calcium supplementation (1000-1200 mg daily)
  • Consider vitamin A, E, K if deficient
  • Dermatitis herpetiformis: Dapsone for symptom control; rash resolves with strict gluten-free diet over months to years
  • Referral to registered dietitian experienced in celiac disease
  • Screen first-degree relatives (10% prevalence in first-degree relatives)
  • Monitor for complications: Repeat tTG-IgA at 6-12 months to assess dietary adherence; repeat DEXA after 1-2 years; rare lymphoma risk requires vigilance for persistent symptoms despite adherence

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