Neonatology: fever

• Body temperature is an important parameter routinely measured as part of a clinical examination.  
• Pyrexia (fever) is defined as an elevation in core body temperature and in the neonatal calf can be taken as a temperature greater than 39.5°C.
•  Signs:
  • Clinical signs may vary widely depending on etiology.
  • If multiple cases of pyrexia are present, appropriate biosecurity protocols should be instigated due to the high likelihood of an infectious disease.
• Diagnosis:
  • Initial investigations should include:
    • A detailed history.
    • Clinical examination.
  • Full hematology may be beneficial at this stage:
    • A low white cell count with a left shift and presence of band neutrophils in indicative of a severe infection.
  • Microbial testing of blood samples - searching for antibody or antigen.
    • If there is any doubt as to the causal organism of a herd problem, then it will be necessary to identify the pathogen which may involve further blood testing or other sampling (swabs, BAL etc).
    • Blood testing may require paired serology and careful interpretation. However, positive results will justify the time and expense, so as to target management practices and treatment appropriately.
• Treatment:
  • The specific treatment plan will depend on the pathology identified and is beyond the scope of this article.
  • Whilst a diagnosis is being pursued in the critical patient, symptomatic treatment should be employed, including intravenous fluid therapy and nonsteroidal anti-inflammatories as indicated.
  • Attempts should be made to identify the cause of the pyrexia prior to administering antimicrobial therapy.  
• Prognosis: dependent upon etiological agent.

Public health considerations

• Some etiological agents, eg Salmonella spp are zoonotic.