Sequelae and complications of <i>Streptococcus equi</i> subspecies <i>equi</i> infections in the horse
Authors: Whelchel D. D., Chaffin M. K.
Journal: Equine Veterinary Education
Summary
Strangles caused by *Streptococcus equi* subspecies *equi* typically presents with lymph node abscessation in the submandibular and retropharyngeal regions, yet this classical form carries a relatively favourable prognosis; however, complications and long-term sequelae can substantially alter clinical outcomes and mortality risk. Whelchel and Chaffin's 2009 review examined the full spectrum of post-strangles complications, encompassing guttural pouch empyema, bastard strangles (metastatic abscessation in distant sites), and immune-mediated conditions including purpura haemorrhagica, myopathies and myocarditis. Understanding these potential complications is critical for equine practitioners, as they fundamentally change how we counsel owners on prognosis and long-term management, particularly when horses present with systemic signs that extend beyond the acute phase of infection. The authors' comprehensive appraisal highlights that whilst uncomplicated strangles remains manageable, vigilance for secondary complications—especially immune-mediated sequelae—is essential to identify horses at higher risk of deterioration and to implement appropriate therapeutic interventions before irreversible tissue damage occurs.
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Practical Takeaways
- •While uncomplicated strangles has a good prognosis, vigilant monitoring for complications like guttural pouch empyema and bastard strangles is essential as these dramatically affect outcomes
- •Be aware of immune-mediated sequelae (purpura haemorrhagica, myocarditis) that can develop during or after strangles infection, as these require different management approaches
- •Complications significantly increase mortality risk, so early recognition and appropriate management of secondary manifestations are critical to patient survival
Key Findings
- •Strangles classically presents with abscessation of submandibular, submaxillary, or retropharyngeal lymph nodes and carries low mortality in uncomplicated cases
- •Complications and sequelae of S. equi infection can significantly worsen prognosis and increase mortality rates
- •Systemic sequelae include immune-mediated diseases such as purpura haemorrhagica, myopathies, and myocarditis