Chronic Diarrhea
\n\n Summary 17\n\n ● Chronic diarrhea (>4 weeks) can be osmotic, secretory, inflammatory or fatty diarrhea.\n● Fecal osmotic gap is helpful to point toward osmotic diarrhea\n● Iron, Ca & folate are absorbed in proximal bowel;\n○ while B12 is absorbed in ileum.
What our notes say
- \n\n Summary 17\n\n ● Chronic diarrhea (>4 weeks) can be osmotic, secretory, inflammatory or fatty diarrhea.\n● Fecal osmotic gap is helpful to point toward osmotic diarrhea\n● Iron, Ca & folate are absorbed in proximal bowel;\n○ while B12 is absorbed in ileum. (L23-Chronic Diarrhea)
- \nA 3-year-old child is brought to your office because of recurrent upper respiratory\ninfections and recurrent urinary tract infections, as well as chronic diarrhea. (Kaplan Pediatrics pdf-notes 201506051322 - flattened (2))
- Gastrointestinal symptoms: Ask about painful swallowing (odynophagia indicates esophageal candidiasis or CMV) and chronic diarrhea lasting over two weeks (suggests *Cryptosporidium*, *Microsporidia*, or *Isospora belli*). (HIV and opportunistic infections)
- *Stage 3:* Advanced symptoms; unexplained severe weight loss, chronic diarrhea over one month, persistent fever, oral candidiasis, pulmonary TB, severe bacterial infections. (HIV and opportunistic infections)
- Laboratory and diagnostic studies: chosen on the history, acute vs. chronic diarrhea. (ACUTE AND CHRONIC DIARRHOEA)
- Tx of chronic diarrhea depends on the specific etiology and may be: (ACUTE AND CHRONIC DIARRHOEA)
Study material on Chronic Diarrhea
- Chronic Diarrhea and Malabsorption
- L23-Chronic Diarrhea
- 7. Approach to a child with diarrhea & constipation
- BABY NELSON PEADS
- Kaplan Pediatrics pdf-notes 201506051322 - flattened (2)
- ACUTE AND CHRONIC DIARRHOEA
- L5-Diarrhea
- Oral stations
- Chemical Pathology MCQs: Clinical Chemistry, Endocrine & Renal — MCQ Bank
- Immuno Pathology MCQs
- Chemical Pathology MCQs
Practice questions on Chronic Diarrhea
A 45-year-old woman with chronic diarrhea presents with weakness. Labs: Na⁺ 138 mmol/L, K⁺ 3.0 mmol/L, Cl⁻ 105 mmol/L, HCO₃⁻ 15 mmol/L. What is the likely diagnosis?
- Normal anion gap metabolic acidosis
- Increased anion gap metabolic acidosis
- Metabolic alkalosis
- Respiratory acidosis Correct
Answer: A. Anion gap = 138 - (105 + 15) = 18 (normal range). Diarrhea causes bicarbonate loss leading to normal anion gap acidosis. ## Case-Based MCQs Section 2: Kidney Function & Renal Pathology
A patient with chronic diarrhea has a pH of 7.25, PaCO₂ 38 mmHg, and HCO₃⁻ 17 mmol/L. What is the acid-base disturbance?
- High anion gap metabolic acidosis Correct
- Respiratory alkalosis
- Metabolic alkalosis
- Normal anion gap metabolic acidosis
Answer: D. Diarrhea causes bicarbonate loss without organic acid accumulation, resulting in normal anion gap metabolic acidosis.
A 42-year-old man has weight loss, small joint arthritis, recurrent bacterial respiratory infections, chronic diarrhea with Giardia, hemolytic anemia, and low IgA 70, IgG 303, IgM 64. Normal T cells, slightly reduced B cells. Most likely condition?
- Bruton agammaglobulinemia
- HIV infection
- Diabetes mellitus
- Common variable immunodeficiency
Answer: D. Low but not absent immunoglobulins + normal T cells + slightly reduced B cells + bacterial and Giardia infections in an adult = common variable immunodeficiency (CVID). B cells cannot differentiate into plasma cells.
A 30-year-old man has weight loss, chronic diarrhea, then develops Pneumocystis pneumonia, CMV retinitis, and oral candidiasis. Most likely lab finding?
- CD4 lymphocyte count of 100/microliter
- cANCA titer of 1:256
- ANA titer of 1:1024
- Serum IgA of 10 mg/dL
Answer: A. Multiple opportunistic infections (Pneumocystis, CMV, Candida) = AIDS. CD4 count below 200/microliter is the threshold at which AIDS-defining opportunistic infections occur in HIV infection.
A 44-year-old man has lifelong mild chronic diarrhea and minor respiratory infections. During a blood transfusion after a car accident, he develops an anaphylactic transfusion reaction. Most likely underlying disease?
- Common variable immunodeficiency
- Graft versus host disease
- Systemic lupus erythematosus
- Selective IgA deficiency
Answer: D. Anaphylaxis during blood transfusion + lifelong mild GI and respiratory issues = selective IgA deficiency. These patients develop anti-IgA antibodies and react anaphylactically to IgA in transfused blood products.