Equis ISSN 2398-2977

Foal: shock

Contributor(s): Kristopher Hughes, Ruth Morgan, Mary Rose Paradis, Jarred Williams

Introduction

  • Shock is defined as a state in which tissues and organs receive an inadequate oxygen supply most commonly due to inadequate blood flow.
  • Cause: the most common reasons for shock in the neonatal foal include sepsis, hypoglycemia, hypovolemia and hypothermia, all of which compromise the blood flow to organs.
  • Signs: recumbency, signs of depression, cold limbs and ears, hypothermia, decreased peripheral pulse quality, seizures, injected mucous membranes, oral petechiae, enophthalmos, decreased jugular refill.
  • Diagnosis: clinical signs, history, decreased blood pressure, low blood glucose, failure of passive transfer, hypovolemia, neutropenia, Increased blood lactate, blood gas abnormalities acidosis, hypoxemia, high sepsis score.
  • Treatment: intranasal oxygen, intravenous fluid therapy, inopressor therapy, careful warming of body core, broad spectrum antibiotics, plasma transfusion, supportive nutrition (including but not limited to glucose supplementation).
  • Prognosis: guarded to poor.

Pathogenesis

Etiology

Predisposing factors

General

Pathophysiology

  • Shock results when tissues or organs have an insufficient supply of oxygen to meet the need of the cells.
  • It is usually a result of inadequate blood flow, eg due to hypovolemia.
  • When tissues have an inadequate supply of oxygen the cells start to die and organ failure can ensue.
  • Septicemia results in a systemic inflammatory response syndrome which can lead to hypotension and inadequate blood flow. Systemic inflammatory response decreases vascular tone resulting in hypovolemia and altered distribution leading to hypoperfusion.
  • Colostrum provides both immunologic support as well as blood glucose maintenance.
  • Foals may not transition to gluconeogensis resulting in hypoglycemia which further weakens foal.
  • Hypothermia may develop, especially if ambient temperature is low.
  • Lack of colostrum predisposes foal to bacterial infection.
  • Decrease oxygen delivery to organ systems.
  • Multi-organ failure or dysfunction.

Timecourse

  • Often seen in the first 48-72 h of life.
  • Rapid progression.

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.
  • Hurcombe S D A et al (2012) Serum protein concentrations as predictors of serum immunoglobulin G concentration in neonatal foals. J Vet Emerg Crit Care 22 (5), 573-579 PubMed.
  • Dickey E J et al (2011) Hypoxic ischemic encephalopathy - what can we learn from humans? J Vet Intern Med 25 (6), 1231-1240 PubMed.
  • Corley K T T & Hollis A R (2009) Antimicrobial therapy in neonatal foals. Equine Vet Educ 21 (8), 436-448 VetMedResource.
  • Hollis A R et al (2008) Blood glucose concentrations in critically ill neonatal foals. J Vet Intern Med 22 (5), 1223-1227 PubMed.
  • Hollis A R et al (2008) Effects of norepinephrine and combined norepinephrine and fenoldopam infusion on systemic hemodynamics and indices of renal function in normotensive neonatal foals. J Vet Intern Med 22 (5), 1210-1215 PubMed.
  • Corley K T T et al (2007) Bacteraemia in neonatal foals: clinicopathological differences between Gram-positive and Gram-negative infections, and single organism and mixed infections. Equine Vet J 39 (1), 84-89 PubMed.
  • Peek S F et al (2006) Prognostic value of clinicopathologic variables obtained at admission and effect of antiendotoxin plasma on survival in septic and critically ill foals. J Vet Intern Med 20 (3), 569-574 PubMed.
  • Nguyen H B, Rivers E P, Knoblich B P et al (2004) Early lactate clearance is associated with improved outcome in severe sepsis and septic shock. Crit Care Med 32 (8), 1637-1642 PubMed.
  • Palmer J E (2004) Fluid therapy in the neonate: Not your mothers fluid space. Vet Clin North Am Equine Pract 20 (1), 63 PubMed.
  • Delinger R P (2003) Cardiovascular management of septic shock. Crit Care Med 31(3), 946-955 PubMed.

Other sources of information

  • Palmer J E (2006) Foal in Hemodynamic Shock. In: Equine Neonatal Medicine: A Case Based Approach. Ed: Paradis M R. Elsevier, USA. pp 121-134.
  • Palmer J E (2002) When Fluids are not Enough: Inopressor Therapy. In: Proc 8th International Vet Emergency & Critical Care Symposium. San Antonio.


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