Current fatality rate of suspected cyclopeptide mushroom poisoning in the United States

This study was designed to determine the fatality rate of suspected cyclopeptide-containing mushroom ingestions reported to the National Poison Data System (NPDS).

Although silibinin reportedly improves survival in suspected cyclopeptide-containing mushroom ingestions, the greater than 20% untreated fatality rate that is often cited is based on decades-old data. An ongoing open-label silibinin trial will likely use historical cases as comparators. A recent single poison control center (PCC) study showed a fatality rate of 8.3%. This study was designed to validate those findings in the NPDS.

This study was an 11-year (1/1/2008-12/31/2018) retrospective review of suspected cyclopeptide-containing mushroom ingestions reported to NPDS. Inclusion and exclusion criteria were the same as the ongoing silibinin trial: Age >2-years-old; history of eating foraged mushrooms; gastrointestinal symptoms within 48 h of mushroom ingestion; and aminotransferases above the upper limit of normal within 48 h after ingestion. Each original participating PCC confirmed eligibility, diagnosis, treatment, and outcome on included cases.

During the study period, 8,953 mushroom exposures were reported to NPDS, of which 296 met inclusion criteria. The PCC survey response rate was 60% (28/47 PCCs), and the individual case response rate was 59% (174/296). Twenty-six cases were subsequently excluded leaving 148 included cases. The overall mortality rate was 8.8% (13/148). Mortality in silibinin/silymarin-treated vs untreated cases was 9.5% (4/42), vs 8.5% (9/106), respectively. A mycologist identified mushrooms in 16.9% of cases (25/148), of which 80% (20/25) were cyclopeptide-containing. Among these confirmed cases, the mortality rate was 10% (1/10) in both silibinin/silymarin-treated and untreated cases.

The contemporary mortality rate of patients with presumed cyclopeptide-mushroom poisoning is only 8.8%. This likely represents improved supportive care for patients with acute liver injury and should be considered the current standard for historical controls in the United States.