Lactose Intolerance
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Introduction
Lactose intolerance is a common causes of diarrhea, resulting from a deficiency in the enzyme lactase.
The Case of...
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.
Pathophysiology
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.
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
Differential Diagnosis
Other causes of chronic diarrhea should be considered.
Treatments
A lactose-free diet is recommended. Soy forumlas can be given to infants.
Lactase-containing pills or milk is available.
Consequences and Course
Resources and References
Topic Development
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