Celiac Disease and Tropical Sprue Quiz

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Questions and Answers

What is the next step after a positive antibody test for celiac disease?

Begin dapsone therapy for skin manifestations.

Undergo an esophagogastroduodenoscopy (EGD) with small bowel biopsy. (correct)

Initiate a gluten-free diet and monitor symptoms.

Start yearly anti-tTG antibodies monitoring.

Which of the following histologic findings are characteristic of celiac disease?

Increased villous height and decreased intraepithelial lymphocytes.

Flattening or loss of crypts and intraepithelial lymphocyte infiltration. (correct)

Normal mucosal architecture with no signs of inflammation.

Crypt hyperplasia with a decrease in mucosal fold scalloping.

What is the primary treatment for celiac disease?

Regular endoscopic surveillance.

Adopting a gluten-free diet for life. (correct)

Supplementation with iron and vitamin B12.

Short-term dapsone therapy.

A patient with dermatitis herpetiformis is most likely to show which finding on small bowel biopsy?

Small bowel gluten enteropathy. (C) Signup and view all the answers

Which of the following ingredients should be avoided on a gluten-free diet?

All of the above. (D) Signup and view all the answers

What is the primary characteristic that distinguishes Non-celiac Gluten Sensitivity from Celiac Disease?

The absence of elevated immune markers or pathological changes. (C) Signup and view all the answers

An oral inhibitor of transglutaminase 2 is being investigated for Celiac Disease, what is its primary purpose?

To attenuate mucosal injury during gluten consumption. (A) Signup and view all the answers

Which of the following is considered the primary cause of Tropical Sprue?

Proximal small bowel bacterial overgrowth. (B) Signup and view all the answers

What is a common nutritional deficiency associated with Tropical Sprue, particularly in the early stages?

Folic acid deficiency (B) Signup and view all the answers

What is an important differential diagnosis to consider with Tropical Sprue, due to similar symptoms of diarrhea and weight loss?

Intestinal Lymphoma (C) Signup and view all the answers

What is the definition of a 'FODMAP'?

Fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (C) Signup and view all the answers

Which of the following is a drug type used in the treatment of IBS-D?

Serotonin antagonists (C) Signup and view all the answers

What is the definition of 'dysentery'?

Diarrhea with visible blood or mucus and fever (D) Signup and view all the answers

What is the time frame that defines acute diarrhea?

Less than 2 weeks (C) Signup and view all the answers

Which of the following is NOT a typical symptom of dehydration assessed during a physical exam?

Increased heart rate (D) Signup and view all the answers

Which organism is most likely associated with recent antibiotic use or hospital stay?

Clostridium difficile (D) Signup and view all the answers

Which of the following organisms is primarily associated with the consumption of raw or unpasteurized dairy or meats?

Listeria (C) Signup and view all the answers

What is the most common cause of acute diarrhea worldwide?

Bacterial, viral and parasitic infections (C) Signup and view all the answers

Which of the following is NOT considered a significant risk factor for constipation?

Male sex (D) Signup and view all the answers

What is the primary characteristic of disordered stool movement in the context of constipation?

Disrupted movement through the colon and rectum (B) Signup and view all the answers

Which of these is a cause of slow transit constipation?

Enteric nerve hypofunction (D) Signup and view all the answers

Which condition is NOT classified as a neurologic cause of constipation?

Diabetes Mellitus (B) Signup and view all the answers

Which of the following bacterial pathogens is most commonly associated with consumption of fried rice?

Bacillus cereus (D) Signup and view all the answers

Which class of medications is LEAST likely to directly contribute to constipation?

NSAIDs (B) Signup and view all the answers

Which of the following symptoms should prompt further evaluation for constipation?

Blood in stool (C) Signup and view all the answers

A patient presents with severe bloody diarrhea accompanied by renal failure. Which of the following pathogens would be the most likely cause?

Shiga-toxin producing E.coli (STEC) (C) Signup and view all the answers

Which of the following does not typically require a microbiology workup for acute diarrhea?

Patient with diarrhea lasting 4 days (B) Signup and view all the answers

What is the recommended daily intake of dietary fiber for managing constipation?

25 g/day (B) Signup and view all the answers

Which laxative type works by increasing the fecal mass and stool water absorption?

Bulk-forming (D) Signup and view all the answers

What is the primary focus in the treatment of acute diarrhea?

Preventing or treating dehydration (A) Signup and view all the answers

Why are antibiotics generally not indicated in the treatment of most cases of acute diarrhea?

Most cases are viral, and antibiotics promote resistance (C) Signup and view all the answers

In which of the following conditions is the use of anti-motility agents like loperamide contraindicated?

Diarrhea with mucoid stools (C) Signup and view all the answers

Which of the following is not a recognized cause of bloody stools?

Norovirus (D) Signup and view all the answers

A patient has traveled to a developing country and now has diarrhea. Which of the following is least likely to be the culprit?

Bacillus cereus (D) Signup and view all the answers

Which of the following best describes the mechanism of action for stimulant laxatives?

They increase intestinal motor activity. (A) Signup and view all the answers

A patient with chronic constipation is considering natural alternatives. Which of the following options performed similarly to or better than daily psyllium in studies?

Prunes and kiwi fruit (A) Signup and view all the answers

What is the primary mechanism by which stool softeners such as docusate facilitate bowel movements?

Lowering the surface tension of stool. (D) Signup and view all the answers

Which of the following is a potential risk with chronic use of stimulant laxatives?

Hypokalemia (D) Signup and view all the answers

For a patient experiencing severe constipation with a suspected distal obstruction, which form of medication should be used?

Bisacodyl suppository (C) Signup and view all the answers

When are peripherally acting mu-opioid receptor antagonists (PAMORAs) most appropriately used for opioid-induced constipation?

When preventive measures with osmotic and/or stimulant laxatives fail. (B) Signup and view all the answers

What is the mechanism of action of guanylate cyclase-c receptor agonists in the management of constipation?

They stimulate intestinal secretion and motility. (B) Signup and view all the answers

Which of the following enemas should be avoided in elderly individuals due to the risk of severe hypotension and electrolyte disturbances?

Sodium phosphate enema (C) Signup and view all the answers

Study Notes

Clinical Intestines - Part 2

Objectives include understanding nutrient absorption, common malabsorption causes (pancreatic insufficiency, celiac sprue, etc.), major IBS risk factors, clinical manifestations, and potential treatments for acute and chronic diarrhea and constipation.

Outline

Malabsorption:
- Fat, carbohydrate, and protein malabsorption
- Exocrine pancreatic insufficiency
- Celiac disease
- Tropical sprue
- Small intestinal bacterial overgrowth (SIBO)
- Whipple's disease
Irritable Bowel Syndrome (IBS)
Acute Diarrhea
Chronic Diarrhea
Constipation

Malabsorption

Definition: Impaired nutrient transport across the apical membrane of intestinal cells.
Global malabsorption: Widespread mucosal diseases (celiac sprue, Crohn's disease), or loss of absorptive surface (surgical resection or intestinal bypass).
Selective malabsorption: Inability to absorb a single nutrient (e.g., pernicious anemia) or a limited number (fat-soluble vitamins).

Malabsorption - Pathogenesis

Steps for normal nutrient absorption:
- 1. Luminal processing
- 1. Absorption into enterocyte
- 1. Transport into the circulation
Malabsorption results from impairment of one or more steps.

Fat Absorption

Most dietary fat absorbed in the proximal two-thirds of the jejunum.
Normally >94% of dietary fat is absorbed.
Fat absorption is essential for intake of fat-soluble vitamins (A, D, E, and K).
Steps to fat absorption:
- 1. Emulsification by mastication and gastric mixing
- 1. Hydrolysis by lipases from tongue, stomach, and pancreas
- 1. Stabilization of emulsion by bile salts forming micelles
- 1. Repackaging into chylomicrons within enterocytes
- 1. Reabsorption of bile salts in the terminal ileum and return to the gallbladder for reuse (enterohepatic circulation).

Fat Malabsorption

Causes:
- Biliary system: Bile duct obstruction, autoimmune pancreatitis, infections, malignancy, choledocholithiasis
- Intestinal wall: Infiltration (lymphoma, Crohn's Disease, celiac disease, immunodeficiency), protein amyloidosis.
- Other: use of medications like azathioprine, phenytoin.
Symptoms: History of oil droplets in toilet bowl is highly suggestive of steatorrhea. Stool tests (fecal fat or Sudan III stain).

Carbohydrate Absorption

Starch, sucrose, and lactose are common digestible carbohydrates (CHO).
CHO are broken down by amylases (pancreas and salivary) and intestinal disaccharidases into monosaccharides for absorption.
Cellulose, a plant disaccharide, cannot be digested in the small intestine but fermented by bacteria in the colon, releasing gas.

Carbohydrate Malabsorption

Causes:
- Pancreatic amylase deficiency
- Reduced disaccharidases
- Decreased absorptive surface (celiac, Crohn's, small bowel resection)
- Unabsorbable carbohydrates (sorbitol)
Symptoms: Watery diarrhea, excessive gas, and bloating. Breath tests (hydrogen, methane, or CO2) are helpful in diagnosis.

Protein Absorption

Initial digestion by gastric pepsins.
Pancreatic peptidases in duodenum break protein to amino acids (AAs) and dipeptides/tripeptides, which are absorbed in intestinal brush border.

Protein Malabsorption

Causes:
- Deficiency of pancreatic bicarbonate and proteases (chronic pancreatitis, cystic fibrosis)
- Loss of intestinal absorptive surface (celiac, Crohn's, small bowel resection)
Low protein states are typically due to malnutrition, liver disease, or proteinuria, and rarely from malabsorption. Measure stool alpha-1 antitrypsin.

Vitamin, Mineral, and Trace Element Absorption

Most vitamins and minerals (iron, calcium) absorbed in the proximal half of the small intestine.
Vit B-12 and Mg are absorbed in the terminal ileum.
Nutritional status determines the amount absorbed (e.g., calcium regulated by vitamin D, iron regulated by hepcidin).

Malabsorption Workup

Suspect in patients with weight loss and/or nutritional deficiencies.
History: Chronic intestinal diseases, prior bowel surgery or radiation, prior ETOH abuse, or pancreatitis.

Exocrine Pancreatic Insufficiency (EPI)

Exocrine pancreas produces enzymes for fat, protein, and starch digestion.
Chronic damage or pancreatic outlet issues result in diminished enzyme delivery to the duodenum and altered digestion.
Clinical Manifestations: Early symptoms include chronic abdominal pain and bloating. Late symptoms include maldigestion, weight loss, chronic diarrhea, and steatorrhea (high fecal fat). Steatorrhea typically only appears after >90% loss of pancreatic exocrine function. Also, related malabsorption of vitamins (A, D, E, K and B12).
Common causes: Chronic pancreatitis (alcohol), pancreatic cancer, and cystic fibrosis (children).

EPI - Diagnosis

Presumptive dx in patients with chronic pancreatitis, diabetes, abdominal pain, diarrhea, and weight loss with suggestive radiographic findings (pancreatic atrophy, scattered calcifications, ductal changes).
Key to rule out pancreatic or duct cancer with advanced imaging.
Indirect tests (fecal elastase-1) and direct tests (secretin test) are used.

EPI - Treatment

Dietary fat reduction, alcohol avoidance, and vitamin supplements.
Oral replacement of pancreatic enzymes with each meal and snack is expensive.

Lactose Intolerance

Characterized by abdominal pain, diarrhea, bloating, and flatulence after lactose ingestion.
Lactase, the enzyme that breaks down lactose, is present in high levels at birth but wanes with age.
High prevalence in some populations (Asians, Native Americans).
Lower prevalence in Northern Europeans.

Lactose Intolerance - Mechanism

Lactose is converted to glucose and galactose in the small intestine and then absorbed. In lactase-deficient individuals, a significant amount of lactose passes undigested to the colon.
Colonic bacteria ferment lactose, producing short-chain fatty acids and gas (hydrogen, CO2, and methane).

Lactose Intolerance - Diagnosis

Lactose-hydrogen breath test measures hydrogen gas levels after lactose ingestion.
Oral lactose load assessment can be helpful but is more subjective.

Celiac Disease (Gluten-sensitive Enteropathy or Sprue)

Inappropriate T-cell reactivity to ingested gluten causes inflammatory changes to the small intestinal mucosa in genetically susceptible individuals.
Affects 1.4% of individuals globally, highest rates in Europeans.
Gluten, a protein found in wheat, rye, barley, and some oat cultivars, is the trigger.
Multisystem disorder: Inflammation in small intestine, malabsorption, diarrhea, vitamin deficiencies, chronic abdominal pain, and weight loss. Increased risk of premature death and malignancy (lymphoma).

Celiac Disease - Genetics

99% of celiac patients have HLA-DQ2 and/or HLA-DQ8 compared to ~40% of the population. Haplotype testing only somewhat helpful to rule out Celiac.
Families— Siblings (8.9%), parents (3.0%), offspring (7.9%)—have increased risk.
Also, autoimmune conditions like type 1 diabetes and autoimmune thyroiditis have increased risk.

Celiac Disease - When to Test

No general population screening guidelines.
Consider genetic screening for first-degree relatives.
Serology testing if patients experience:
- Chronic or recurrent diarrhea or constipation
- Malabsorption (especially vitamin deficiencies)
- Unexplained weight loss
- Chronic abdominal pain.

Celiac Disease - Antibody Tests

Anti-tissue transglutaminase (tTG-IgA) is the test of choice.
Other tests include endomysial (EMA-IgA), anti-gliadin antibodies, and anti-deaminated gliadin peptide.
Patients must be consuming gluten for at least 6 weeks for accurate testing.

Celiac Disease - Diagnosis

If antibody testing is positive, perform an EGD with small bowel biopsy to confirm.
Gross findings: scalloping of mucosal folds.
Histological findings: flattening/loss of crypts and intraepithelial lymphocyte infiltration.

Celiac Disease - Treatment

Gluten-free diet for life.
Monitor symptoms and anti-tTG antibodies yearly.
Repeat small bowel biopsy is not necessary if asymptomatic.
Monitor relevant laboratory findings like CBC, iron, vitamin D, and B12.

Tropical Sprue

Malabsorption syndrome believed to be caused by proximal small bowel bacterial overgrowth, especially in tropical countries or travelers staying in a region for >1 month.
Western hemisphere (Cuba, Haiti, Dominican Republic, and Puerto Rico)
Eastern hemisphere (India, Pakistan, and SE Asian nations).

Tropical Sprue – Etiology

Starts as an infectious enteritis that evolves into chronic diarrhea and weight loss.
Toxigenic coliform organisms in the duodenum.
Often associated with folic acid and B12 deficiencies and megaloblastic anemia.
Multiple differential diagnoses including parasites, HIV, celiac disease, intestinal lymphoma.

Tropical Sprue - Diagnosis and Treatment

Exclude other causes (parasites, HIV, celiac disease).
Duodenal biopsy reveals gross and histological similarities to celiac disease.
Oral tetracycline combined with folic acid/B12 for 3-6 months.

Small Intestine Bacterial Overgrowth (SIBO)

Small bowel becomes colonized with excessive colonic organisms, disrupting CHO, protein, and fat absorption.
Risk factors: Intestinal hypomotility, chronic pancreatitis, anatomic disorders, immune disorders, and gastric hypochlorhydria.

SIBO - Clinical Presentation and Diagnosis

Patients report excess bloating, flatulence, abdominal pain, and watery diarrhea.
Difficult to diagnose due to non-specific symptoms that often overlap with other conditions like IBS, celiac disease, EPI, or IBD.
Diagnosis in patients with persistent symptoms is often made using a timed carbohydrate breath test (lactose or lactulose) or jejunal aspirate, where presence of bacterial concentration ≥10^3 CFU/mL.

SIBO - Treatment

Antibiotics (rifaximin is the antibiotic of choice).
Recurrence is common, and additional antibiotic courses might be necessary.
Elemental diets (AA's, glucose, simple fats) have shown promise in SIBO treatment.

Whipple's Disease

A multisystem disease manifesting with joint symptoms, chronic diarrhea, malabsorption, and weight loss, caused by infection with Tropheryma whipplei, a common soil bacteria.
Relatively rare, estimated at 30 cases per year in the US.
Diagnosis with PAS stain and PCR.
Treatment: IV antibiotics followed by oral antibiotics for at least one year.

IBS (Irritable Bowel Syndrome)

Functional disorder marked by chronic abdominal pain and altered bowel habits (diarrhea, constipation, or both).
Very common, affecting about 9% of men and 14% of women in the US. Onset typically in the 2nd or 3rd decade and more common in younger age groups.
Associated with increased health care costs and absenteeism. 25–50% of referrals to gastroenterologists are for IBS.
Frequent associated conditions include fibromyalgia, chronic fatigue syndrome, GERD, and dyspepsia; psychiatric conditions like depression or anxiety; and somatization.

IBS - Clinical Features

Crampy abdominal pain, variable location and severity.
Pain often worsened by stress.
Altered bowel habits (diarrhea, constipation, or both), often with mucus or tenesmus, or diarrhea alternating with constipation.

IBS - Pathophysiology

Uncertain. No consistent pathophysiologic mechanism has been identified. However, infectious gastroenteritis in 10-20% of patients can lead to post-infectious IBS.

IBS - Proposed Mechanisms

Altered gastrointestinal microbiome
Brain-gut dysregulation
Transient infection
Altered endocrine metabolism (serotonin)
Neuronal plasticity
Altered motility
Increased mucosal permeability
Bile acid malabsorption
Altered mucosal immune function
Food hypersensitivity

IBS - Diagnosis

Diagnosis is made by using ROME IV criteria: Recurrent abdominal pain at least 1 day a week for at least 3 months with two or more criteria: pain brought on or relieved by defecation; associated with changes in stool frequency; associated with changes in stool form.

IBS - Subtypes

IBS-Constipation Predominant
IBS-Diarrhea Predominant
IBS-Mixed Bowel Habits
IBS-Unclassified

IBS - Evaluation (Diagnosis)

Rule out other conditions (red flags).
Age-appropriate screening for colon cancer.
CBC and CRP.

IBS - Treatment

Reassurance and education are critical.
Dietary approach (first-line treatment):
- Daily soluble fiber (psyllium)
- Low FODMAP diet (reduction in IBS symptoms, pain, and bloating)
- Consider lactose and gluten avoidance.
Physical activity, stress reduction, and CBT (cognitive behavioral therapy).

Diarrhea

Diarrhea is defined as 3+ watery bowel movements per day.
Types:
- Acute (<2 weeks)
- Persistent (2-4 weeks)
- Chronic (>4 weeks)
Dysentery is diarrhea with visible blood or mucus, often associated with fever and abdominal pain.

Acute Diarrhea

One of top 10 causes of death for all people and top 5 for infants <5 years worldwide.
Primarily due to infections (viruses, bacteria, and parasites). A "nuisance disease" in resource-rich countries that typically self-resolves.
Evaluation: History, PE (rule out inflammatory conditions or severe dehydration, dark or scant urine, low skin turgor, dry mucus membranes, orthostatic hypotension).
Stool studies if persistent fevers, bloody stools, severely ill or dehydrated, immunocompromise, or suspected outbreak.

Acute Diarrhea - Treatment

Primarily focus is on preventing/treating dehydration using oral rehydration solutions (water, salt, and sugar).
IV fluids for severe cases.
Early refeeding is usually beneficial but avoid fatty and dairy foods during early recovery.
Probiotics may also be helpful but not always definitively supported by evidence.

Acute Diarrhea - Antibiotics

Antibiotics may shorten the course of acute bacterial diarrhea.
Most viral diarrhea resolves without antibiotics.
Potential side effects: Promotion of antibacterial resistance, disruption of normal flora, potential for C. difficile superinfection, and cost.

Diarrhea - Anti-Motility Agents

Anti-motility agents (loperamide, diphenoxylate) are usually safe, reducing frequency and duration of symptoms. However, avoid use in patients with fevers or bloody/mucoid stools because they can prolong inflammatory diarrhea by causing retention of infectious organisms.
Bismuth might be an alternative.

Chronic Diarrhea

Defined as loose stools, increased frequency, or urgency lasting for >28 days. Affects about 3-5% of US adults. Distinguishing chronic IBS-related diarrhea from organic causes is critical for appropriate treatment.

Chronic Diarrhea - Evaluation

Careful history (diet, prior gut surgery/radiation, alcohol use), physical exam (PE)
History is critical to rule out alarm symptoms.
Labs (CBC, CMP, CRP, and anti-tTG IgA)
If Rome IV criteria, diagnose IBS.
If still unresolved, stool studies or testing for infectious, inflammatory, or fatty stools (also consider CT, EGD, or colonoscopy)

Constipation

<3 stools/week for >3 months.
Patients often describe difficulty defecating, straining, and feeling of incomplete evacuation.
Absence of loose stools in the absence of laxative use is a key distinguishing feature from IBS.
US prevalence: 14% (age >18); 33% (age >60) and 80% of older nursing home residents!

Constipation-Etiology

Slow transit (enteric nerve hypofunction)
Dyssynergistic defecation (dyscoordinated pelvic floor/rectal muscles)
IBS-C (most common)
Secondary causes- medications, neurologic conditions (MS, Parkinson's), endocrine disorders (diabetes, hypothyroidism), and structural disorders (colon cancer).

Constipation-Evaluation

Careful history (esp. medications), physical exam (PE) necessary.
Rule out alarm features.
If appropriate, perform labs (CBC, CMP).
Stool studies or imaging (CT, EGD, colonoscopy) if underlying concerns are present.
Stool for occult blood if warranted.

Constipation - Treatment

Minimize constipating medications.
Education (don't obsess about BM frequency).
Increase dietary fiber (25 g/day recommended).
Increase fluid intake.
Increase exercise.
Use laxatives if appropriate (bulk-forming, osmotic, stimulants, or stool softeners). Choose appropriate treatment type based on patient's type of constipation.

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Test your knowledge on celiac disease, its diagnosis, treatment, and associated conditions like Tropical Sprue. This quiz includes questions on antibody testing, histologic findings, nutritional deficiencies, and more. Perfect for medical students and healthcare professionals!