Breath with ammonia odor [Uremic fetor]
The odor of ammonia on the breath—described as urinous or “fishy” breath—typically occurs in end-stage chronic renal failure. This sign improves slightly after hemodialysis and persists throughout the course of the disorder, but it isn’t of great concern.
Ammonia breath odor reflects the long-term metabolic disturbances and biochemical abnormalities associated with uremia and end-stage chronic renal failure. It’s produced by metabolic end products blown off by the lungs and the breakdown of urea (to ammonia) in the saliva. However, a specific uremic toxin hasn’t been identified. In animals, breath odor analysis has revealed toxic metabolites, such as dimethylamine and trimethylamine, that contribute to the “fishy” odor. The source of these amines, although still unclear, may be intestinal bacteria acting on dietary chlorine.
History and physical examination
When you detect ammonia breath odor, the diagnosis of chronic renal failure will probably be well established. Look for associated GI symptoms so that palliative care and support can be individualized.
Inspect the patient’s oral cavity for bleeding, swollen gums or tongue, and ulceration with drainage. Ask the patient if he has experienced a metallic taste, loss of smell, increased thirst, heartburn, difficulty swallowing, loss of appetite at the sight of food, or early morning vomiting. Because GI bleeding is common in patients with chronic renal failure, ask about bowel habits, noting especially melena or constipation.
Take the patient’s vital signs. Watch for any indications of hypertension (the patient with end-stage chronic renal failure is usually somewhat hypertensive) or hypotension. Be alert for other signs of shock (such as tachycardia, tachypnea, and cool, clammy skin) and altered mental status. Any significant changes can indicate complications, such as massive GI bleeding or pericarditis with tamponade.
Medical causes
End-stage chronic renal failure
Ammonia breath odor is a late finding in end-stage chronic renal failure. Accompanying signs and symptoms include anuria, skin pigmentation changes and excoriation, brown arcs under the nail margins, tissue wasting, Kussmaul’s respirations, neuropathy, lethargy, somnolence, confusion, disorientation, behavior changes, irritability, and emotional lability. Later neurologic signs that signal impending uremic coma include muscle twitching and fasciculations, asterixis, paresthesia, and footdrop. Cardiovascular findings include hypertension, myocardial infarction, signs of heart failure, pericarditis, and even sudden death and stroke. GI findings include anorexia, weight loss, nausea, heartburn, vomiting, constipation, hiccups, and a metallic taste. Oral signs and symptoms may include stomatitis, gum ulceration and bleeding, and a coated tongue. The patient has an increased risk of peptic ulceration and acute pancreatitis. Uremic frost, pruritus, and signs of hormonal changes, such as impotence or amenorrhea, may also appear.
Special considerations
Ammonia breath odor is offensive to others, but the patient may become accustomed to it. As a result, remind him to perform frequent mouth care, particularly before meals because reducing the foul taste and odor may stimulate his appetite. A half-strength hydrogen peroxide mixture or lemon juice gargle helps neutralize the ammonia; the patient may also want to use commercial lozenges or breath sprays or to suck on hard candy. Advise him to use a soft-bristled toothbrush or sponge to prevent trauma. If he can’t perform mouth care, do it for him and teach his family members how to assist him.
Maximize dietary intake by offering the patient frequent small meals of his favorite foods, within dietary limitations.
Pediatric pointers
Ammonia breath odor also occurs in children with end-stage chronic renal failure. Provide hard candy to relieve bad taste and odor. If the child can gargle, try mixing hydrogen peroxide with flavored mouthwashes.
Patient counseling
Involve the patient at an early stage in the various aspects of treatment to help prepare him for any complicated training that may be needed later—for example, if he needs dialysis or transplantation. Explain dietary and drug therapies.
Book Source Details
- Book Title: Professional Guide to Signs & Symptoms (Fifth Edition)
- Author(s): Springhouse
- Year of Publication: 2006
- Copyright Details: Professional Guide to Signs & Symptoms (Fifth Edition), Copyright © 2006 Lippincott Williams & Wilkins.
Other Book Chapters Related to Breath odor
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Copyright Details: Professional Guide to Signs & Symptoms (Fifth Edition), Copyright © 2008 Williams & Wilkins.
More About Causes of Breath odor
» Next page: Halitosis (Professional Guide to Signs & Symptoms (Fifth Edition))
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