Lapis ISSN 2398-2969

Hyperthermia

Synonym(s): High/elevated body temperature

Contributor(s): Anna Meredith, Livia Benato

Introduction

  • Cause: hyperthermia occurs when the body over produces or over absorbs heat in high environmental temperatures and hot climate.
  • Signs: weakness, anorexia, dehydration and increased respiratory rate; seizure and death in severe cases.
  • Diagnosis: history, rectal temperature and general evaluation of the rabbit.
  • Treatment: hyperthermia requires immediate treatment, including cooling the animal down and supportive treatment such as oxygen supplementation and intravenous fluid therapy.
  • Prognosis: poor.
  • Normal rabbit body temperature is 38.5-40°C.
  • Hyperthermia occurs when body temperature is >40.5°C.
  • Hyperthermia is different from fever:
    • Feveris an increase in body temperature that results from an increase in the hypothalamic thermoregulatory center due to bacterial infection.
    • Hyperthermiais an increase in body temperature due to an increase of heat production or absorption without changes of the hypothalamic thermoregulatory center.
  • The ideal environmental temperature for a rabbit is 15-21°C.
  • Because rabbits are unable to sweat or pant, and cannot dissipate heat efficiently, higher environmental temperatures can lead to hyperthermia that, if not treated promptly, can be life-threatening.

Print off the Owner factsheet onHyperthermia - overheating  Hyperthermia - overheating  to give to your clients.

Presenting signs

  • Weakness.
  • Lethargy.
  • Lateral recumbency.
  • Increased respiratory rate.
  • Dyspnea.
  • Hypersalivation.
  • Reduced food intake and anorexia.
  • Dehydration.
  • Increased rectal temperature >40.5°C.
  • Muscle tremors.
  • Diarrhea.
  • Hyperemia.

Acute presentation

  • Cyanosis.
  • Blood tinged fluids from mouth and nose.
  • Collapse.
  • Ataxia.
  • Seizures.
  • Death.

Geographic incidence

  • Hyperthermia is a condition that can occur worldwide.
  • However, it is more common in countries with a hot climate and significant temperature variations during the day.

Age predisposition

  • Older rabbits.

Sex predisposition

  • Pregnant does.
  • Heat stress can also lead to infertility in male rabbits.

Cost considerations

  • Costs depend on the severity of the condition and the duration of therapy.
  • In rabbit farms, infertility in male rabbits can lead to major economic loss.

Special risks, eg anesthetic

Pathogenesis

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Diagnosis

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Treatment

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Prevention

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Sequelae

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Amici A, Canganella F & Bevilacqua L (1998) Effects of high ambient temperature in rabbits; metabolic changes, caecal fermentation and bacterial flora. World Rabbit Science (3-4), 319-324 ResearchGate
  • Lin M T, Kao T Y, Su C F et al (1994) Interleukin-1 beta production during the onset of heat stroke in rabbits. Neurosci Lett 174 (1), 17-20 PubMed.
  • Tharwat E E, Khadr A F, Amin S O et al (1994) Effect of hot environment on the reproductive performance of New Zealand White rabbit. Cahiers Options Méditerranéennes 8, 613-618 ResearchGate
  • Glowicki K & Ryba M (1984) Changes of minute ventilation in rabbits in experimental hyperthermia. Acta Physiol Pol 35 (2), 171-176 PubMed.
  • Shih C J, Lin M T & Tsai S H (1984) Experimental study on the pathogenesis of heat stroke. J Neurosurg 60 (6), 1246-1252 PubMed.

Other sources of information

  • Kennen K M & Mitchell M A (2009) Rabbits.In: Manual of Exotic Pet Practice. Eds: Mitchell M A & Tully T N. Saunders Elsevier. pp 375-405. 
  • Deeb B J & Carpenter J W (2004) Neurologic and Musculoskeletal diseases. In: Ferrets, Rabbits and Rodents Clinical Medicine and Surgery. 2nd edn. Eds: Quesenberry K E & Carpenter J W. pp 203-210.
  • Harcourt-Brown F (2002) Cardiorespiratory Disease. In: Textbook of Rabbit Medicine. ButterworthHeinemann. pp 324-334.
  • Boydell P (2000) Nervous System and Disorders. In: BSAVA Manual of Rabbit Medicine and Surgery. Ed: Flecknell P. pp 57-61.
  • Shaw D H & Ihle S L (1997) Fever and Hyperthermia. In: Small Animal Internal Medicine. Lippincott William & Wilkins. pp 59-63. 
  • Stefanini M (1975) Heat Stroke. In: Injuries of the Brain and Skull, Part I. Handbook of Clinical Neurology. Eds: Vinken P J & Bruyn G W. pp 669-681.


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