Difference between revisions of "Hyperammonemia"

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==Background==
 
==Background==
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===Pathophysiology===
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*Acquired: liver failure results in shunting of blood from the liver to the inferior vena cava, decreased filtration of blood and removal of nitrogen-containing toxins by the liver, and then hyperammonemia.
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*Congenital: Defect in one of the enzymes of the urea cycle, which leads to lower production of urea from ammonia.
  
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===Types===
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*Primary
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**Caused by several [[inborn errors of metabolism]]
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**Characterized by reduced activity of urea cycle enzymes
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*Secondary
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**Caused by inborn errors of intermediary metabolism (i.e. reduced activity of enzymes that are not part of the urea cycle)
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***Normally from acute or chronic [[liver failure]]
  
 
==Clinical Features==
 
==Clinical Features==
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==Evaluation==
 
==Evaluation==
 
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===Acquired vs. Congenital===
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*Acquired
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**Diseases that result in [[liver failure]]
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**Medications (e.g. [[valproic acid]] overdose)
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**Severe dehydration (from small intestinal bacterial overgrowth)
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**Glycine toxicity (CNS symptoms and nausea)
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*Congenital
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**Genetic
  
 
==Management==
 
==Management==
 
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*Treat underlying disorder
  
 
==Disposition==
 
==Disposition==
 
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*Depends on cause
  
 
==See Also==
 
==See Also==

Latest revision as of 10:45, 18 July 2020

Background

Pathophysiology

  • Acquired: liver failure results in shunting of blood from the liver to the inferior vena cava, decreased filtration of blood and removal of nitrogen-containing toxins by the liver, and then hyperammonemia.
  • Congenital: Defect in one of the enzymes of the urea cycle, which leads to lower production of urea from ammonia.

Types

  • Primary
  • Secondary
    • Caused by inborn errors of intermediary metabolism (i.e. reduced activity of enzymes that are not part of the urea cycle)

Clinical Features

Differential Diagnosis

Evaluation

Acquired vs. Congenital

  • Acquired
    • Diseases that result in liver failure
    • Medications (e.g. valproic acid overdose)
    • Severe dehydration (from small intestinal bacterial overgrowth)
    • Glycine toxicity (CNS symptoms and nausea)
  • Congenital
    • Genetic

Management

  • Treat underlying disorder

Disposition

  • Depends on cause

See Also

External Links

References