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578 Lead Toxicosis

• Direct visualization of the larynx for intuba- increased respiratory rate/effort or increase/ SUGGESTED READING
tion can reduce risk of iatrogenic trauma. change in respiratory sounds may indicate Basdani EE, et al: Upper airway injury in dogs
VetBooks.ir ventilation can be maintained by temporary are better monitored when not in an oxygen AUTHOR: Lori S. Waddell, DVM, DACVECC
impending crisis. If possible, these patients
• Long-term intubation for positive-pressure
secondary to trauma: 10 dogs (2000-2011). J Am
Anim Hosp Assoc 52:291-296, 2016.
tracheostomy to prevent laryngeal damage.
cage, allowing any airway noises caused by acute
Technician Tips obstruction to be heard. EDITOR: Megan Grobman, DVM, MS, DACVIM
Careful monitoring is necessary because patients
can develop acute airway obstruction. Any

Lead Toxicosis Client Education
Sheet

Clinical Presentation
BASIC INFORMATION • Lead can also interfere with vitamin D
DISEASE FORMS/SUBTYPES metabolism, resulting in derangements of
Definition Can occur after a single acute exposure or after calcium absorption and metabolism.
Lead toxicosis occurs most commonly when lead chronic exposure if lead accumulates in the body
is ingested, resulting in neurologic, hematologic, DIAGNOSIS
and/or gastrointestinal (GI) effects. HISTORY, CHIEF COMPLAINT
• Observed or suspected exposure to lead- Diagnostic Overview
Synonyms containing agents Physical exam findings are nonspecific. Suspect
Plumbism, lead poisoning • Recent remodeling in older homes or agri- lead intoxication if there are GI and neurologic
cultural buildings should increase suspicion signs or the history suggests lead in the animal’s
Epidemiology of lead exposure. environment, with the characteristic RBC
SPECIES, AGE, SEX • Acute toxicosis: vomiting, anorexia, ataxia, abnormalities or metallic foreign bodies in the
Any dog or cat, although cats may be at higher tremors, and seizures GI tract on radiographs. Whole blood lead level
risk due to grooming behaviors if there are • Chronic toxicosis: slow onset of vomiting, is the confirmatory test of choice.
lead particles available (e.g., flakes of lead-based diarrhea, anorexia, abdominal pain, regurgita-
paint). Younger dogs may be at higher risk tion (uncommon due to megaesophagus in Differential Diagnosis
due to an increased tendency to lick or chew cats, not dogs), lethargy, weight loss, weak- • Viral encephalitides (rabies, distemper)
objects. Immature animals absorb more lead ness, behavior changes, ataxia, blindness, • Sterile encephalitides (granulomatous)
from the GI tract than adults; immature animals tremors and seizures • Toxoplasma
are also at higher risk because lead can cross • Hepatic encephalopathy
the blood-brain barrier more readily than in PHYSICAL EXAM FINDINGS • Idiopathic epilepsy
adults. • Acute: vomiting, lethargy, ataxia, tremors, • Neoplasia
aberrant behavior, seizures • Causes of vomiting (p. 1294)
RISK FACTORS • Chronic: weight loss, vomiting, diarrhea,
• Living in a home that was built before 1977 abdominal pain, lethargy, pale mucous Initial Database
may increase risk because this is when lead membranes, aberrant behavior, tremors, • CBC (more common to see changes with
paint was banned. If a home painted with ataxia, seizures chronic toxicosis)
lead paint is remodeled or the paint is sanded • Neurologic exam: mental dullness or lethargy ○ Nucleated RBCs (nRBCs) found in 54%
or otherwise damaged, there is an increased is frequently seen. Ataxia, muscle tremors, of dogs with lead intoxication
risk of exposure to lead. and intermittent seizures may also be noted. ○ Between 5 and 40 nRBCs/100 white blood
• Lead absorption can be increased in animals Asymmetrical deficits are not consistent with cells (WBCs) without severe anemia is
deficient in calcium, zinc, iron, or vitamin lead poisoning. highly suggestive of lead poisoning.
D. ○ If > 40 nRBCs/100 WBCs, rule out
• Availability of other lead sources: lead curtain Etiology and Pathophysiology myeloproliferative disease
or fishing weights, older painted toys, older • Inhibition of enzymes associated with heme ○ Microcytic, hypochromic, regenerative
gasoline or batteries, linoleum, lead solder, production results in microcytic, hypochro- anemia in approximately 8% of dogs
some foreign miniblinds, radiators, and mic, regenerative anemia with nucleated red with lead poisoning
hobbies such as stained-glass or pottery blood cells (RBCs) and basophilic stippling. ○ Basophilic stippling can be seen in approxi-
making. • Competition with calcium ions results in mately 25% of dogs with lead toxicosis.
• Feeding animals meat/scraps from hunting storage of lead in bones, alteration of nerve ○ ± Anisocytosis, poikilocytosis, polychro-
may also be a source of lead if shot is present and muscle transmission, and displacement masia, echinocytosis, target cells
in the carcass. of calcium from calcium-binding proteins. ○ ± Mature leukocytosis
• Inhibition of membrane-associated enzymes • Serum chemistries and urinalysis are typically
CONTAGION AND ZOONOSIS can result in increased RBC fragility and normal for lead intoxication; can help rule out
Lead sources can be common to humans and renal tubular epithelial injury. other differentials (e.g., hepatic encephalopathy)
animals living in the same environment. If an • Lead may interfere with gamma-aminobutyric • Radiography
animal is diagnosed with lead intoxication, acid (GABA) production or activity in the ○ May show metal-density material in GI
owners should be made aware of risks to central nervous system (CNS), leading to tract or joint spaces
themselves and to any infants and children loss of inhibitory impulses and resulting in ○ Absence of metallic material does not rule
living in the household. seizures. out lead poisoning because source may be
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