Canis ISSN: 2398-2942

Hops toxicity

Synonym(s): Humulus lupulus

Contributor(s): Nicola Bates, Simon Tappin

Introduction

  • Cause: ingestion of fresh or spent hops.
  • Signs: hyperthermia.
  • Diagnosis: based on history of exposure and clinical signs.
  • Treatment: gastrointestinal decontamination and cooling measures.
  • Prognosis: good if pyrexia is controlled; more guarded in dogs with uncontrolled pyrexia or complications. 

Pathogenesis

Etiology

  • Poisoning usually occurs after ingestion of spent hops, typically from a bin or compost heap.
  • Poisoning also occur with fresh hops, or more rarely with ingestion of other plant material.

Predisposing factors

General

  • None.

Specific

  • Dogs with pyrexia Pyrexia: overview are potentially at greater risk of complications if in a hot environment. 

Pathophysiology

  • The cause of malignant hyperthermia in dogs after ingestion of hops is unknown.
  • Hops contain numerous chemicals including flavonoids, essential oils, resins and phenolic compounds (including the tannins coumaric acid, gallic acid and caffeic acid).
  • There may be a component of hops that uncouples oxidative phosphorylation. When this occurs in mitochondria the energy generated which is normally used to synthesize ATP is dissipated as heat, resulting in hyperthermia Hyperthermia.

Timecourse

  • Signs can occur within 2.5-8 hours; death can occur within 6 hours of ingestion.
  • Recovery may take 24-72 hours.

Epidemiology

  • Dogs in areas where brewing occurs are at risk of exposure, eg home brewing or in breweries.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Duncan K L, Hare W R, Buck W B (1997) Malignant hyperthermia-like reaction secondary to ingestion of hops in five dogs. JAVMA 220 (1), 31-33 PubMed.
  • Stevens R (1967) The chemistry of hop constituents. Chem Revs 67, 19-71 ACS Publications.

Other sources of information

  • Flint C (2016) Hops. In: Blackwell’s Five Minute Veterinary Consult Clinical Companion. Small Animal Toxicology, 2nd edn. Hovda L R, Brutlag A G, Poppenga R H, Peterson K L (eds). Ames, Iowa: Wiley Blackwell, pp 491-496.

Organisation(s)


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