Gastroenterology Consult

Reason for Consultation

Chronic diarrhea and iron deficiency anemia

History of Present Illness

Marcus Vance is a 42-year-old male referred by Dr. S. Patel.

Pt presents for evaluation of a 4-month history of non-bloody watery diarrhea and progressive fatigue.

Referred for investigation of altered bowel habits, mild postprandial abdominal cramping, and unexplained iron deficiency anemia.

Reports 4 to 5 loose, watery BMs daily (Bristol Type 6-7) for the past 4 months. Worse postprandially, particularly after heavy or carbohydrate-rich meals. Associated with moderate bloating, flatulence, and generalized fatigue. Endorses an unintentional weight loss of 4 kg over 3 months. Denies hematochezia, melena, nocturnal diarrhea, fevers, chills, nausea, or emesis. No recent travel or antibiotic exposure.

Previously trialed loperamide (Imodium®) 2 mg PO PRN with minimal temporary relief. Self-initiated lactose-free diet for 3 weeks with no improvement in symptom frequency or stool consistency. Started oral iron supplementation 1 month ago, which caused mild nausea without altering diarrhea.

Past Medical History

Autoimmune hypothyroidism, appendectomy (15/08/2010)

Medications

• levothyroxine (Synthroid®) 100 mcg PO daily
• ferrous fumarate (Palafer®) 300 mg PO daily
• loperamide (Imodium®) 2 mg PO PRN

Allergies

Penicillin (maculopapular rash)

Social History

Lives in Toronto with his wife and two children; independent in all ADLs.

Never-smoker. Alcohol: 2-3 standard drinks per week (wine). Denies recreational substance use.

Works full-time as a high school mathematics teacher.

Family History

Mother has rheumatoid arthritis. Maternal aunt has celiac disease. No family history of IBD, colorectal, or gastric malignancy.

Physical Exam

Vitals (14/05/2024 10:15): BP 118/74 mmHg, HR 78 bpm, Temp 36.8 °C, Weight 72 kg, BMI 22.8 kg/m². General: Alert, oriented, NAD. Mild conjunctival pallor. GI: Abdomen soft, mildly distended. Mild diffuse tenderness on deep palpation, no rebound or guarding. Normoactive bowel sounds. No hepatosplenomegaly or palpable masses. DRE: normal sphincter tone, brown guaiac-negative stool, no masses. Derm: Pruritic papulovesicular rash noted on bilateral extensor elbows, suspicious for dermatitis herpetiformis.

Investigations

• Labs (02/05/2024): Hb 108 g/L, MCV 74 fL, Ferritin 8 ug/L, WBC 6.2 x 10^9/L, Plt 310 x 10^9/L, Cr 78 umol/L, CRP 2.1 mg/L, TSH 2.4 mIU/L, Albumin 36 g/L. Tissue transglutaminase (tTG) IgA > 100 U/mL (normal < 15), Total IgA 2.1 g/L. Stool C. diff, O&P, and C&S negative. Fecal calprotectin 38 ug/g.
• Colonoscopy (10/05/2024): Normal colonic mucosa to cecum and terminal ileum. Random colonic biopsies negative for microscopic colitis.
• EGD (10/05/2024): Scalloping of duodenal folds and mosaic mucosal pattern in D2. Biopsies (reported 13/05/2024) confirm Marsh 3b villous atrophy with crypt hyperplasia and intraepithelial lymphocytosis; gastric biopsies negative for H. pylori.
• CT Abdomen/Pelvis (20/04/2024): Unremarkable solid organs; mild fluid-filled small bowel loops without wall thickening, stricture, or lymphadenopathy.

Assessment and Plan

1. Celiac Disease

Probable diagnosis of celiac disease confirmed by markedly elevated tTG-IgA, classic malabsorptive symptoms, iron deficiency anemia, dermatitis herpetiformis, and Marsh 3b duodenal histology.

Differential diagnosis includes Crohn's disease, microscopic colitis, small intestinal bacterial overgrowth (SIBO), and non-celiac gluten sensitivity.

• Check baseline micronutrient panel: Vitamin D (25-OH), Vitamin B12, folate, zinc, and copper. Order baseline DEXA scan to screen for metabolic bone disease.
• Discontinue loperamide. Continue ferrous fumarate 300 mg PO daily; switch to alternate-day dosing to optimize absorption and minimize GI upset. Add colecalciferol (Vitamin D3) 2,000 IU PO daily.
• Initiate strict, lifelong gluten-free diet (GFD). Eliminate all wheat, barley, and rye. Continue alcohol moderation and regular physical activity.
• Follow up in GI clinic in 3 months with repeat CBC, ferritin, and tTG-IgA to monitor serologic and clinical response.
• Refer to a registered dietitian specializing in celiac disease for comprehensive GFD education and label-reading guidance. Refer to dermatology for biopsy confirmation and management of probable dermatitis herpetiformis.

2. Iron Deficiency Anemia

• Secondary to proximal small bowel malabsorption from celiac disease. Expect gradual resolution of anemia and replenished iron stores following mucosal healing on a strict GFD and ongoing oral iron supplementation. Repeat CBC and ferritin in 3 months; will consider IV iron if oral intolerance develops or stores fail to improve.

Additional Notes:

• Discussed the autoimmune pathophysiology of celiac disease, the necessity of strict adherence to a GFD to prevent long-term complications (osteoporosis, nutritional deficiencies, enteropathy-associated T-cell lymphoma), and strategies to avoid cross-contamination.
• Advised patient to monitor stool frequency and weight. Instructed to seek urgent care for red-flag symptoms including melena, hematochezia, severe unrelenting abdominal pain, persistent vomiting, or syncope.
• Addressed patient's concern regarding the risk to his children; recommended screening first-degree relatives with tTG-IgA and total IgA via their primary care provider.