1st March 2013, Volume 126 Number 1370

Sally F Belcher, Tom R Morton

Background

There are about 30 species of Coriariaceae found around the world including southern Europe, eastern Asia, south and central America, and New Zealand.1 The six species native to New Zealand and the Chatham islands (Coriaria angustissim, C. arborea, C. lurida, C. plumosa, C. pteridoides and C. sarmentosa) are all known by the name tutuand are mostly deciduous shrubs found in grassland. There is variety in appearance and distribution as seen with Coriaria arborea, or “tree tutu”, which may become an evergreen tree growing to 6 metres in height and being found in coastal and montaine forest.2

The primary toxin, tutinwas discovered in 18703 and is found in all varieties of tutu1,2. It is a picrotoxin-like toxin which acts as an antagonist at amino acid receptors within the CNS, especially the medullary, cortical, respiratory, vasomotor, and autonomic centers4. In cultured neurons tutin causes significant suppression of GABA type A receptors5, resulting clinically in anxiety and seizures.

Tutu has gained notoriety for its poisonous nature and is responsible for the greatest percentage of stock poisoning by plants in New Zealand.1 Indeed the first two sheep brought to New Zealand by Captain James Cook in 1773 both died after eating the plant, just a few days after their release in Queen Charlotte Sound.3,6

A number of settlers, particularly children who were fond of the palatable berries, also died2,7. Fatal poisoning has also been reported in elephants, including one from a travelling circus who ate roadside tutu shrubs in 1957.2,3,7,8

The whole plant is toxic except for the soft, black or purple fleshy petals (known as berries).2 Maori were certainly aware that the berries contained highly toxic seeds and that careful separation was needed to avoid poisoning.2 The strained juice though was valued and used for medicinal purposes, to flavour bland foods, and to brew a sweet wine.1,2

Alfred Saunders, the first settler to step ashore in Nelson from the Fifeshire in 1842, described his initial encounter with the local Maori:

“But we soon gave the Maoris another and more real cause for uneasiness by our eagerness to taste their nice-looking tutu berries. They knocked them out of our hands as we lifted them to our lips. They took a handful of the seeds, and turned up their eyes with an expression of horror. They squeezed out some juice through a suspicious looking cloth, and offered us a drink, which was really delicious, at the same time holding the seeds in one hand and fencing us off with the other, which we understood to mean that we must not eat or touch the seeds. We thought that their actions were most likely based on some superstitious reason. We little knew, as we left them, how much real anxiety we had given them, or that we owed our lives to their extreme vigilance.”9

Today, whilst livestock poisoning continues to occur, little is heard of direct tutu poisoning in people.2 Indirect poisoning though has occurred sporadically in recent times through the consumption of toxic honey.2 Bees that collect honeydew exudates from vine hopper insects (Scolypopa sp.) that have fed on the sap of Coriaria arborea10 can produce honey containing tutin and its toxic derivative hyenanchin (a hydroxytutin) (J. Fountain, personal communication, November 5, 2012).

In 1905 Dr Austin described his treatment of a family who, following ingestion of wild honey, suffered prolonged vomiting, then sustained convulsions over a five hour period followed by several days of delirium in the mother's case.11 Since 1889 there have been 141 reported cases of illness from ingesting toxic honey and four cases of death in New Zealand, with a further 30 cases of children becoming ill after honey was sent to a school in England.10

The last known cases occurred in 2008, when 22 people fell ill after eating honey from the Coromandel Peninsula which was found to have high levels of tutin.10,12 This resulted in the Food Safety Authority calling for tougher controls on the honey supply.10

Clinical manifestations

Symptoms of tutu poisoning described in case reports from the turn of the twentieth century include vomiting, giddiness, delirium, great excitement, convulsions and coma, ending in death.3 For those who survived, long-term ill health and severe memory impairment has been described.3

Our literature review found the last case report was published in 1972 and described an elderly Maori lady who, following taking a tea made from the leaves, suffered confusion and vomiting.13 The New Zealand Poisons Centre describes the onset of nausea and vomiting after a characteristic delay of 3–6 hours, followed by tremor then repeated tonic-clonic seizures and finally respiratory compromise (see Table 1).

When death occurs (usually due to respiratory arrest) it is within 24 hours, and in non-fatal cases, duration of symptoms is dose-dependent and may last 24 hours to 5 days.

Table 1. Severity of Coriariaceae poisoning (acute effects by organ system)
Organ System
Mild Symptoms
Moderate Symptoms
Severe Symptoms
Neurological

Drowsiness, dizziness, tremor, anxiety, excitement, confusion
Generalised weakness, amnesia, incoordination, stupor, tonic-clonic seizures, coma
Gastrointestinal
Dry mouth, nausea
Vomiting, diarrhoea, frequent defecation

Musculoskeletal

Tremor
Muscle spasm, convulsions
Respiratory

Tachypnoea
Dyspnoea, pulmonary congestion, chest pain, rhonchi on auscultation, respiratory arrest
Cardiovascular

Tachycardia

Genitourinary

Urinary frequency

Ocular


Blurred vision
Dermatologic


Jaundice-like appearance
Source: Table compiled from information provided by TOXINZ.4

Treatment

The New Zealand Poisons Centre currently an eight-hour period of observation in a facility with advanced life support capability, a bedside ECG and serum electrolytes. There is no specific antidote, gastric decontamination and enhanced elimination are not recommended, and serum levels are not of clinical use. Treatment is then supportive and based on severity of symptoms (see Table 1). A benzodiazepine is considered the mainstay of treatment, especially in those with neurological symptoms4.

Case reports

In April 2012, three patients presented to Nelson Hospital Emergency Department (ED) on the advice of local garden centre staff who were concerned they had eaten tutu berries. The trio had been camping in the Kahurangi National Park for some weeks and were tramping beside the Cobb Reservoir near Takaka. They came across “wild berries” which they described as small and black/red in colour.

Cautious tasting revealed a sweet fruit “like a blueberry”, and assuming this meant they were edible, the trio went on to consume “hundreds” of berries each. At around two hours post ingestion (2-HPI) the trio developed nausea, but they attributed this to their travelling on an unsealed road in the back of a truck. However the nausea did not abate after the journey ended and so, worried the berries were to blame, they went to a garden centre.

Patient A had fortuitously taken a photograph of the berries (see below) which staff identified as tutu and advised urgent medical attention.

Photograph 1. Taken by patient A (confirmed to be Coriaria arborea by Dr John Steel of the Botany Department, University of Otago)

Belcher-1

Photograph 2. Coriaria arboreaberries

Photograph 3. Coriaria arborealeaves

Belcher-2
Belcher-3
Source: Reproduced with permission of photographer, Wayne Bennett.

The trio arrived at ED at 5-HPI and were seen by a triage nurse. Patient A was a 26 year old male, European tourist with no past medical history of note, taking no medications and no reported allergies; patient B was a healthy 21-year-old female, American tourist; patient C was a healthy 20-year-old female, New Zealand European, with a family history of epilepsy (father).

Patients A and B both complained of moderate nausea, whilst patient C said her nausea was mild. Patient A additionally complained of fatigue and a dry mouth and was noted to be febrile (37.8oC) and “excitable”. Shortly before being seen by medical staff, at 5:30-HPI, patient A had a tonic-clonic seizure which lasted two minutes and spontaneously resolved followed by a post-ictal period of 20 minutes.

There was no deterioration prior to the seizure which was sudden and unexpected. He remained tachycardic (110 bpm) but neurological exam was unremarkable with no tremor and normal reflexes. He was given diazepam 10 mg PO and the decision was made to admit for overnight observation.

During this time patient B developed an elevated heart rate (100 bpm) and became highly anxious, then at 6:30-HPI had a 2-minute, self-resolving tonic-clonic seizure. Following a brief post-ictal period, she too was given diazepam 10 mg PO.

The decision was made to admit all three for observation and to treat patient C prophylactically with diazepam. Patient C at this point had vital signs within normal range and reported feeling entirely well. Following transfer to the intensive care unit (ICU), at 9-HPI, patient A had a second 2-minute tonic-clonic seizure and received a second dose of diazepam. Patients B and C were given a further prophylactic dose of diazepam 5 mg PO.

Overnight observation in ICU was hitherto unremarkable for all three patients. At 20-HPI patients A and B were reviewed and found to have poor recollection of the events (felt to be expected post-seizures), but otherwise had normal vital signs and examination. Patient C continued to be entirely stable. Bloods were taken in ED at 6-HPI, and repeated next day at 20-HPI. Patient A initially had a minimally elevated INR (1.3) which normalised the next day (normal LFTs both samples) and a slight drop in haemoglobin from 147 to 127. Patient B and C's bloods were unremarkable for both samples.

All three patients had normal serial ECGs. The trio were discharged at 22-HPI with no follow-up arranged. Attempts to contact all three patients after 1 week and 1 month were unsuccessful.

Discussion

The tutu plant has gained an infamous reputation due to its devastating effects on New Zealand stock and a number of deaths amongst early settlers. However, in recent decades there has been a paucity of published case reports detailing human poisoning.

Tutu poisoning as described by previous authors and the National Poisons Centre (NPC) begins with mild symptoms including nausea and dry mouth, progresses to moderate symptoms including tachycardia, vomiting and excitability, then severe symptoms, predominantly seizures, develop before death from respiratory arrest.

We present three cases, two of whom developed symptoms with a similar progressive pattern. Patient A, at 5-HPI had moderate symptoms (ongoing nausea, pyrexia and excitability) then at 5:30-HPI developed severe symptoms (first seizure) which continued until 9-HPI (second seizure). Patient B evolved likewise but her seizures occurred at 6:30-HPI, the onset of which, like patient A, was rapid and without warning.

The NPC recommends hospital monitoring for 8 hours post ingestion then, if asymptomatic, the patient can be discharged. However nausea may occur only after a delay of 6 hours, and, given the lack of recent literature, a physician may be falsely reassured their patient has escaped with mild symptoms only. Based on our experience, the development of severe symptoms was abrupt and unheralded and, with no reliable way of determining which patients will progress as such, disposition must be addressed cautiously.

We would recommend extending the observation period for asymptomatic patients to 12 hours, and for those with mild symptoms to 12 hours or longer. This may lead to admissions of patients who remain asymptomatic; however this must outweigh the consequences of developing potentially life-threatening symptoms post discharge.

In our series, patient C had only mild symptoms but given the progressive course of patients A and B was treated with diazepam. We are therefore unable to conclude whether her symptoms simply self-resolved, or were prevented from worsening. However, we suggest that strong consideration is given to prophylactically treating suspected cases of tutu poisoning with benzodiazepines, even if the patient is only mildly symptomatic.

Table 2. Suggested management of Coriariaceae poisoning based on presenting symptoms
All cases of ingestion
Monitored in facility with advanced life support capability
Monitoring to include ECG and routine bloods
Asymptomatic
Hospital monitoring for 12 hours
Discharge - if remains asymptomatic with normal ECG
Mild symptoms
Hospital monitoring for 12-24 hours
Consider prophylactic benzodiazepines
Moderate symptoms
Hospital monitoring for 12-24 hours
Consider admission to HDU/ICU
Consider prophylactic benzodiazepines
Severe symptoms
Emergency stabilisation (ABC)
Benzodiazepines for seizure management
Source: Information modified from TOXINZ current recommendations.4

Abstract

Aim

We describe three cases of tutu berry (Coriaria arborea) ingestion resulting in tonic-clonic seizures in two individuals and mild symptoms in the third. Tutu poisoning in humans appears to be a rare occurrence; the last reported case in the medical literature being over 40 years ago. We review the literature on tutu poisoning and recommend extending the period of observation for poisoned individuals from 8 hours to 12 hours or longer. We also recommend that prophylactic benzodiazepine use should be considered in those with mild to moderate symptoms of poisoning.

Author Information

Sally F Belcher, Emergency Medicine Registrar; Tom R Morton, Clinical Director and Emergency Medicine Specialist; Emergency Department, Nelson Hospital, Nelson & Marlborough District Health Board, Nelson

Acknowledgements

We thank Dr John Steele, Teaching Fellow at the University of Otago Botany School and Dr John Fountain, Medical Toxicologist at the National Poisons Centre in Dunedin for assisting with our case, particularly in reviewing photograph and confirming its being tutu (Coriaria arborea). In addition we thank Wayne Bennett of Forest Flora and the New Zealand Plant Conservation Network for permission to reproduce photographs.

Correspondence

Dr Sally F Belcher, Emergency Department, Nelson Hospital, Tipahi Street, Nelson 7010, New Zealand.

Correspondence Email

sally.belcher@hotmail.co.uk

References

  1. Poole AL. Tutu. In: An Encyclopaedia of New Zealand; 1966. Retrieved from http://www.teara.govt.nz/en/1966/tutu/1
  2. Connor H, Fountain J. Plants that Poison – a New Zealand Guide. Lincoln, NZ: Manaaki Whenua Press, Landcare Research; 2009.
  3. Fitchett, F. Article XXXIII – A Contribution to our knowledge of the Physiological Action of Tutin. Transactions of the New Zealand Institute 1908;41:286–365.
  4. TOXINZ (National Poisons Centre, New Zealand) (2012). Poisons information – Tutu. Retrieved from http://www.toxinz.com(accessed 01/04/12).
  5. Dixon C, Huang L., Lees G. The plant convulsant tutin does not directly activate glutamate receptors (Proceedings of the 187th Scientific Meeting of the Otago Medical School Research Society, Thursday 17 May 2007). In: N Z Med J. 2007;120(1225). http://journal.nzma.org.nz/journal/120-1255/2574/content.pdf
  6. Cook J. The Journals of Captain James Cook on His Voyages of Discovery. JC. Beaglehole (Ed.). Cambridge and London: Cambridge University Press for the Hakluyt Society; 1974.
  7. Easterfield TH. Art. XLIII.—Studies on the Chemistry of the New Zealand Flora. Transactions of the New Zealand Institute 1900;33:345–55.
  8. Robb J. McGregor Museum: Mollie. 2009. Retrieved from http://mcgregor.sbs.auckland.ac.nz/category/treasures/mollie/
  9. Saunders E, Saunders A. Tales of a Pioneer – Episodes in the Life of Alfred Saunders. Selected and arranged by His Two Youngest Daughters. Christchurch, NZ: L M Isitt Ltd; 1927.
  10. NZFSA (New Zealand Food Safety Authority) (). “Tutin in Honey” Public discussion paper 09/08. 2008. Retrieved fromhttp://www.foodsafety.govt.nz/elibrary/industry/tutin-honey-cover-letter/tutin-in-honey-discussion-paper-final-for-web.pdf orhttp://www.nzsfa.govt.nz
  11. Aubin ED. Poisoning by wild honey (100 years ago). N Z Med J. 2004;117(1199). http://journal.nzma.org.nz/journal/117-1199/1003/content.pdf
  12. NZ Herald. Drought, tutu poisons honey; 2008. Retrieved from http://www.nzherald.co.nz/food/news/article.cfm?c_id=206&objectid=10506819
  13. Chilvers CD. Tutu poisoning in an elderly Maori lady. N Z Med J. 1972;75(477):85–6.