Serum copper elevation from estrogen effect, masquerading as fungicide toxicity

Area of Science:

• Toxicology
• Endocrinology
• Clinical Chemistry

Background:

• Copper toxicity is a known risk associated with copper naphthenate wood preservative.
• Estrogen therapy is recognized to increase serum copper levels.

Observation:

• A 44-year-old female presented with persistently elevated serum copper levels after home exposure to copper naphthenate.
• Despite no further exposure and normal red blood cell (RBC) copper, serum copper remained elevated for 9 months.
• The patient was using oral contraceptives (estrogen).

Findings:

• Serum copper levels were elevated by 30% above normal, peaking at 2301 microg/L.
• Literature review confirmed oral contraceptives routinely elevate serum copper.
• Discontinuation of oral contraceptives for 2 months normalized serum copper levels.

Implications:

• Elevated serum copper in this case was likely due to estrogen, not copper naphthenate exposure.
• Estrogen-induced hypercupremia can confound diagnosis of actual copper toxicity.
• Accurate diagnosis requires considering concurrent medication use affecting copper levels.