Lactose Intolerance

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Introduction

Lactose intolerance is a common causes of diarrhea, resulting from a deficiency in the enzyme lactase.

 

 

 

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Causes and Risk Factors

Primary lactose intolerance is seen in older children and adults, primarily of East Asian or African descent. LI has a prevalence of 80-90% in Chinese

 

Secondary lactose intolerance is transient and follows persisent diarrhea, ie post-infection, with celiac disease, or IBD.

 

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Pathophysiology

 

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Signs and Symptoms

  • history
  • physical exam

History

A history of increased symptoms with lactose containing-foods - milk, cheese, etc is common. However, milk products may be found in unexpected sources.

A trial of lactose-free diet can be helpful.

Physical Exam

Children show no failure to thrive.

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Investigations

  • lab investigations
  • diagnostic imaging

Lab Investigations

Positive hydrogen breath test in children >6

stool shows acid pH and is positive for reducing sugars

Diagnostic Imaging

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Differential Diagnosis

Other causes of chronic diarrhea should be considered.

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Treatments

A lactose-free diet is recommended. Soy forumlas can be given to infants.

Lactase-containing pills or milk is available.

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Consequences and Course

 

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Additional Resources

 

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Topic Development

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