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Fiddlehead Fern Poisoning: A Case Report

  • S. Bryn Dhir
    Correspondence
    Corresponding author: S. Bryn Dhir, International American University College of Medicine, 1255 W 15th Street, Suite 100, Plano, Texas, 75075
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    International American University College of Medicine, Plano, TX
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Published:April 21, 2020DOI:https://doi.org/10.1016/j.wem.2019.12.011
      Outdoor enthusiasts are at a high risk of poisonous side effects after ingestion of wild and raw edible fiddlehead ferns, such as the ostrich fern (Matteuccia struthiopteris) and bracken (Pteridium genus) species, in the United States and Canada. The acute onset of nonlethal side effects manifests with gastrointestinal signs and symptoms and can last from 24 h up to 3 d. This case report is the first to outline the presentation of ingestion of a wild fiddlehead plant in the Carrabassett Valley in Maine, as well as the supportive management for this concerning and self-limiting illness.

      Keywords

      Introduction

      The Matteuccia struthiopteris plant, known as the ostrich fern or fiddlehead, and the bracken fern (Pteridium genus) are a springtime delicacy consumed in the northeastern United States and Canada.
      • Fuller D.
      Non-timber forest products: Goods from the Maine Woods. The University of Maine.
      Although the consumption of large quantities of fiddleheads is common in New England, there are limited reports and information about its poisonous effects. Despite investigations of the plant’s carcinogenic and toxic properties,
      • Newberne P.M.
      Biologic effects of plant toxins and aflatoxins in rats.
      there is no test to detect the toxin responsible for poisonous outbreaks.
      • Hesson C.
      • Drake-Wilke C.
      • Gazaway B.
      • Barrett T.
      Gastroenteritis associated with consumption of fiddlehead ferns. State of Alaska Epidemiology Bulletin No. 23.
      Although consumers are aware of the common practice of parboiling fiddleheads and government health officials
      • Newberne P.M.
      Biologic effects of plant toxins and aflatoxins in rats.
      have provided recommendations for preparation, very few consumers know why this is an important practice. This knowledge gap is in part due to the information provided by the Maine government, which lists the fiddlehead as an edible native perennial. Furthermore, online publications encourage the gathering of fiddleheads and indicate the ferns should be brushed clean, washed, soaked, and steamed or cooked in boiling water.
      Facts on edible wild greens in Maine. The University of Maine Cooperative Extension. Maine’s Department of Agriculture, Conservation and Forestry Bulletin #4060 Web site.
      However, pertinent information from health officials regarding the plant’s potential toxic effects is lacking. To many, the detailed instructions involved in the plant’s preparation is an aspect of a recipe, and few are aware that fiddleheads contain a toxin. Case reports such as this one serve to provide insight into why fiddleheads should be parboiled and should not be consumed raw. In addition to the general public, bushcraft hikers who may rely on foraging for nutrition, plant toxicologists, and physicians managing wilderness medicine cases should be aware of the toxic side effects of wild fiddlehead consumption and the alarming associated symptoms, despite the ultimately benign, self-limited nature of the toxicity.
      Written informed consent was obtained from the patient to report this case.

      Case Report

      This case report describes the toxic ingestion of raw wild fiddlehead crosiers in the Carrabassett Valley, Maine, United States.
      In early spring, a 57 kg, 35-y-old South Asian female hiker from Canada was mountaineering in the high peaks of south Crocker Mountain (total elevation of 1234 m (4050 ft), with a prominence of vertical separation from the main Crocker mountain of 110 m (361 ft); approximate coordinates: 45°02'10” north, 70°22'33” west). Upon successful descent, she picked and ingested 2 raw fiddlehead ferns from the side of the mountain (Figure 1). The fibers surrounding the fiddleheads were manually brushed off, and the crosiers (the upper curled portions of the fern) were ingested. The patient’s hiking partner, a white male native of Maine, approximately 88 kg, also consumed 4 fiddleheads.
      Figure 1
      Figure 1The fiddlehead fern that was consumed by the patient upon descent of the South Crocker Mountain, Carrabassett Valley, Maine. Image used with permission.
      Approximately 3 h after ingestion of the fiddleheads, the patient reported a sudden onset of nausea, exacerbated by heat, external sounds such as talking and music, and the smell of food. The patient did not have chest pain, shortness of breath, or fever. Her hiking partner, who remained with the patient throughout the episode, denied seizure, syncope, altered mental status, hallucinations, or delusions. He did not report any changes to his own health.
      Four hours after ingestion, the patient reported vomiting and diarrhea. She experienced 5 episodes per hour of forceful, painful vomitus consisting of clear yellow-green bile, associated with hematemesis and painful dysphagia secondary to retching. She described periodic sharp, painful abdominal cramps and 5 episodes per hour of secretory diarrhea, without flatus, hematochezia, or pain with defecation. She indicated that the level of pain was a 9 on a pain scale of 1 to 10, with 10 as a relative measure of the worst pain previously experienced. Upon reading on the Internet about an unknown potential toxin in the fiddlehead plant, the northern New England poison center
      Northern New England Poison Center.
      serving the state of Maine was telephoned, and a representative confirmed known reports of acute-onset poisoning after ingestion of fiddlehead ferns. Investigation to rule out other potential confounding variables included a review of allergies, medications, sexual history, events, and foods consumed before onset, which may have included a bacterial or parasitic infection; other variables were found to be noncontributory. Therefore, the patient had a working diagnosis of acute poisoning due to the toxic ingestion of unprepared raw fiddleheads. Supportive care was recommended with fluid resuscitation, and antidiarrheal medication was discouraged. If dehydration was extreme, or if the condition persisted beyond 2 d, the patient was encouraged to seek care at an emergency department.
      Treatment consisted of supportive care, bed rest, and fluids such as sports drinks. Approximately 30 h after symptom onset, the patient gradually increased consumption of liquids in addition to applesauce, canned fruits, and soup, as tolerated. Vomiting and diarrhea resolved by 36 h; however, the patient remained lethargic and reported muscle pain in her back, arms, and abdomen attributed to the forceful muscle contractions while vomiting and overall dehydration. At 48 h after onset, symptoms had resolved, and the patient gradually resumed regular activities and diet.

      Discussion

      The leafy green crosiers of fiddlehead ferns are commonly harvested between mid-May and mid-June and have a cultural significance among Maine’s Native Americans, including the Penobscot, Mi’kmaqs, and Maliseets.
      United States Department of Agriculture
      Culturally and economically important nontimber forest products of northern Maine.
      Vegetation and wild plants are also a source of nutrition for outdoor enthusiasts and bushcraft hikers, and harvesting is enjoyed as a family activity because the ferns are consumed by local residents.
      Centers for Disease Control and Prevention
      Ostrich fern poisoning--New York and Western Canada, 1994.
      Despite the popularity of wild plant foraging in Maine, water hemlock poisoning is the most commonly reported.
      Centers for Disease Control and Prevention
      Water hemlock poisoning--Maine, 1992.
      The specific cause of the poisonous effects of fiddlehead ferns remains unknown, and investigation of the toxin has been limited. Although local Mainers have taken to social media and online blogs to share personal experiences of fiddlehead poisoning, to date there is no available published case incident reported in Maine.
      Many wild plants are edible after proper preparation, and harvesting is typically seasonal. A common example in the United States is pokeweed or pokeberry (Phytolacca americana), the leaves and berries of which must be parboiled before consumption in salads or jellies and jams, respectively. Similarly, the preparation of fiddleheads begins with removing the stems and the brown outer coating of the curled crosier skin, washing, and soaking. It is recommended that fiddleheads then be strained through a colander and washed a second time with cold water to remove residue containing the potential toxin. The final step in the preparation includes boiling or blanching for 10 to 15 min, before cooking and consuming the plant. However, despite the nontrivial meticulous cleaning and preparation process, poisonous effects of the consumption of fiddleheads have previously been reported in the United States and Canada.
      Centers for Disease Control and Prevention
      Ostrich fern poisoning--New York and Western Canada, 1994.
      Cooking preparations of the fern are accepted by consumers as a part of a recipe, rather than as an essential mechanism to remove a toxin.
      Although published case reports of fiddlehead toxicity are limited, a previous study
      Centers for Disease Control and Prevention
      Ostrich fern poisoning--New York and Western Canada, 1994.
      ,
      Centers for Disease Control and Prevention
      Ostrich fern poisoning--New York and Western Canada, 1994.
      investigated an outbreak of food poisoning from consumption of raw or lightly cooked fiddlehead ferns in New York and western Canada. Previously, it was thought that fiddleheads harvested in the coastal provinces of Canada and northeastern United States may have been poisonous or carcinogenic; however, fiddleheads were not considered to be toxic until incidents were reported and known.
      Centers for Disease Control and Prevention
      Ostrich fern poisoning--New York and Western Canada, 1994.
      ,
      Centers for Disease Control and Prevention
      Ostrich fern poisoning--New York and Western Canada, 1994.
      Furthermore, after a flood of the St. John River Valley in northern Maine, the Maine Center for Disease Control and Prevention highlighted extra care in handling and preparing fiddleheads harvested in these regions; however, the reason for this was attributed to potential contamination of floodwaters by bacteria and chemicals, and there was no mention of the existing natural toxin in the ferns.
      Maine Center for Disease Control and Prevention
      Maine CDC emphasizes safe prep and cooking of fiddleheads, especially in flooded northern Maine.
      Similar to the symptoms of toxicity described in the case reports investigated by the Centers for Disease Control and discussed earlier, the patient in this report experienced diarrhea, nausea, vomiting, and abdominal cramps that began within hours of fiddlehead consumption and was self-limited to 36 h. Although the patient was affected, her hiking partner did not report any medical issues; some individuals who consume raw fiddlehead fern crosiers without proper preparation may have an increased predisposition to gastrointestinal toxicity than others owing to genetic polymorphisms that limit hepatic detoxification of plant toxins. The importance of understanding potential genetic polymorphisms is important for patient case considerations because socioeconomic factors, increasing immigration from out of state, and increasing international migration to Maine may predispose patients to toxic side effects. This is of further concern for patients with traditional and cultural practices that include foraging and for those who are unfamiliar with the fern.
      Clinical investigations provide insight into toxicity through the kinetics of hydrogen cyanide in plants and crystalline cyanogenic glucosides found in the fiddlehead plant; these investigations suggest that the amount of crozier eaten and the seasonal variations in consumption are also characteristics to consider in understanding toxicity.
      • Alonso-Amelot M.E.
      • Oliveros-Bastidas A.
      Kinetics of the natural evolution of hydrogen cyanide in plants in neotropical Pteridium arachnoideum and its ecological significance.
      Furthermore, differences in the pathway involved in biochemical processing of these plants have been noted, with decreased international normalized ratios occurring via phylloquinone, also known as vitamin K1, with increased fiddlehead consumption.
      • Bartle W.R.
      • Ferland G.
      Fiddleheads and the international normalized ratio.
      Although studies have yet to determine the specific source of the toxin, thousands of people are poisoned by consuming plants that have not been stored, prepared, or cooked properly.,
      The University of Maine. Facts on Fiddleheads.
      Nonetheless, despite the toxic potential, fiddleheads are a popular delicacy and have made media headlines, with foragers illegally picking them to sell for a profit.
      The Telegraph
      Fiddlehead rustlers threatened with jail as US state tries to curb mass foraging.

      Conclusions

      Although there are reported health benefits of consuming fiddlehead ferns,
      • Bushway A.A.
      • Wilson A.M.
      • McGann D.F.
      • Bushway R.J.
      The nutrient composition of fresh fiddlehead greens.
      their potential to cause poisoning remains a little-known fact in the local community. For those who are aware, the responsible toxin and metabolic biomarkers involved remain unknown. Further investigations are needed to determine the cause of toxicity in the fiddlehead fern and the profile of patients affected. The aim of this case report is to highlight the self-limited manifestation of poisoning symptoms after ingestion of wild, raw fiddlehead ferns and to bring to attention the importance of preparing fiddleheads, which goes beyond instructions for a recipe and should rather be understood as a method to remove tannins and toxins from the fiddlehead fern.
      Acknowledgment: The author would like to thank the operator at the New England Poison Center for providing knowledgeable and empathetic information.
      Financial/Material Support: None.
      Disclosures: None.

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