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=introduction==

 

 

Meconium impaction or retention is the most common cause of colic in the first 24 hours of life and the most common cause of rectal obstruction in foals.<ref>White, N.A, Lessard, P (1986) Risk factors and clinical signs associated with cases of equine colic.  ''Proc Am Ass Equine Practnrs'', 32:637-644.  In: Pusterla, N, Magdesian, K.G, Maleski, K, Spier, S.J, Madigan, J.E (2004) ''Special Article'': Retrospective evaluation of the use of acetylcysteine enemas in the treatment of meconium retention in foals: 44 cases (1987–2002).  ''Equine Vet Educ'', 16(3):133-136.</ref>Meconium is mucilaginous material in the intestine of the term fetus containing a mixture of cellular debris, secretions of the intestinal glands, bile and swallowed amniotic fluid.<ref name="Pusterla">Pusterla, N, Magdesian, K.G, Maleski, K, Spier, S.J, Madigan, J.E (2004) ''Special Article'': Retrospective evaluation of the use of acetylcysteine enemas in the treatment of meconium retention in foals: 44 cases (1987–2002).  ''Equine Vet Educ'', 16(3):133-136.</ref>  It is dark brown to black and cement- or pellet-like in texture.  Most foals defaecate shortly after their first meal, with meconium being evacuated from 3 hours after birth.<ref name="Pusterla">Pusterla, N, Magdesian, K.G, Maleski, K, Spier, S.J, Madigan, J.E (2004) ''Special Article'': Retrospective evaluation of the use of acetylcysteine enemas in the treatment of meconium retention in foals: 44 cases (1987–2002).  ''Equine Vet Educ'', 16(3):133-136.</ref>  Once meconium has been passed, the faeces become a dark yellow, reflecting milk digestion.  Retention is suspected if the foal makes frequent attempts but fails to produce meconium by 12 hours.<ref name="Pusterla">Pusterla, N, Magdesian, K.G, Maleski, K, Spier, S.J, Madigan, J.E (2004) ''Special Article'': Retrospective evaluation of the use of acetylcysteine enemas in the treatment of meconium retention in foals: 44 cases (1987–2002).  ''Equine Vet Educ'', 16(3):133-136.</ref>

Meconium impaction or retention is the most common cause of colic in the first 24 hours of life and the most common cause of rectal obstruction in foals.<ref>White, N.A, Lessard, P (1986) Risk factors and clinical signs associated with cases of equine colic.  ''Proc Am Ass Equine Practnrs'', 32:637-644.  In: Pusterla, N, Magdesian, K.G, Maleski, K, Spier, S.J, Madigan, J.E (2004) ''Special Article'': Retrospective evaluation of the use of acetylcysteine enemas in the treatment of meconium retention in foals: 44 cases (1987–2002).  ''Equine Vet Educ'', 16(3):133-136.</ref>Meconium is mucilaginous material in the intestine of the term fetus containing a mixture of cellular debris, secretions of the intestinal glands, bile and swallowed amniotic fluid.<ref name="Pusterla">Pusterla, N, Magdesian, K.G, Maleski, K, Spier, S.J, Madigan, J.E (2004) ''Special Article'': Retrospective evaluation of the use of acetylcysteine enemas in the treatment of meconium retention in foals: 44 cases (1987–2002).  ''Equine Vet Educ'', 16(3):133-136.</ref>  It is dark brown to black and cement- or pellet-like in texture.  Most foals defaecate shortly after their first meal, with meconium being evacuated from 3 hours after birth.<ref name="Pusterla">Pusterla, N, Magdesian, K.G, Maleski, K, Spier, S.J, Madigan, J.E (2004) ''Special Article'': Retrospective evaluation of the use of acetylcysteine enemas in the treatment of meconium retention in foals: 44 cases (1987–2002).  ''Equine Vet Educ'', 16(3):133-136.</ref>  Once meconium has been passed, the faeces become a dark yellow, reflecting milk digestion.  Retention is suspected if the foal makes frequent attempts but fails to produce meconium by 12 hours.<ref name="Pusterla">Pusterla, N, Magdesian, K.G, Maleski, K, Spier, S.J, Madigan, J.E (2004) ''Special Article'': Retrospective evaluation of the use of acetylcysteine enemas in the treatment of meconium retention in foals: 44 cases (1987–2002).  ''Equine Vet Educ'', 16(3):133-136.</ref>

==Signalment==

==Signalment==

 

Newborn foals. More common in '''colts''' than fillies, particularly if they are overdue. This may be related to a narrower pelvic inlet in colts.<ref>Martens, R.J (1982) Pediatrics. In: Mannsman, R.L, McAllister, E.S '''Equine Medicine and Surgery''' (Third Edition), American Veterinary Publications, Santa Barbara. pp 333-334.  In: Pusterla, N, Magdesian, K.G, Maleski, K, Spier, S.J, Madigan, J.E (2004) ''Special Article'': Retrospective evaluation of the use of acetylcysteine enemas in the treatment of meconium retention in foals: 44 cases (1987–2002).  ''Equine Vet Educ'', 16(3):133-136.</ref>

Newborn foals. More common in '''colts''' than fillies, particularly if they are overdue. This may be related to a narrower pelvic inlet in colts.<ref>Martens, R.J (1982) Pediatrics. In: Mannsman, R.L, McAllister, E.S '''Equine Medicine and Surgery''' (Third Edition), American Veterinary Publications, Santa Barbara. pp 333-334.  In: Pusterla, N, Magdesian, K.G, Maleski, K, Spier, S.J, Madigan, J.E (2004) ''Special Article'': Retrospective evaluation of the use of acetylcysteine enemas in the treatment of meconium retention in foals: 44 cases (1987–2002).  ''Equine Vet Educ'', 16(3):133-136.</ref>

==Aetiology==

==Aetiology==

 

Meconium retention may result from a lack of colostrum ingestion, since colostrum is a natural laxative. Thus foals with meconium retention should also be checked for [[Failure of Passive Transfer|'''failure of passive transfer (FPT)''']]. Intestinal dysmotility may also be an indication of '''perinatal asphyxia'''. Other factors predisposing to meconium retention include maternal malnutrition and other conditions that compromise the foal such as dystocia, prematurity, low birth weight, and dehydration.<ref>Semrad, S.D, Shaftoe, S (1992) Gastrointestinal diseases of the neonatal foal. In: Mills, L '''Current Therapy in Equine Medicine''' (Third Edition), W.B. Saunders, Philadelphia. pp 446-447.  In: Pusterla, N, Magdesian, K.G, Maleski, K, Spier, S.J, Madigan, J.E (2004) ''Special Article'': Retrospective evaluation of the use of acetylcysteine enemas in the treatment of meconium retention in foals: 44 cases (1987–2002).  ''Equine Vet Educ'', 16(3):133-136.</ref>  Most impactions are in the small colon at the pelvic inlet, but retention may also occur in the dorsal or transverse colon.<ref name="Pusterla">Pusterla, N, Magdesian, K.G, Maleski, K, Spier, S.J, Madigan, J.E (2004) ''Special Article'': Retrospective evaluation of the use of acetylcysteine enemas in the treatment of meconium retention in foals: 44 cases (1987–2002).  ''Equine Vet Educ'', 16(3):133-136.</ref>

Meconium retention may result from a lack of colostrum ingestion, since colostrum is a natural laxative. Thus foals with meconium retention should also be checked for '''failure of passive transfer (FPT)'''. Intestinal dysmotility may also be an indication of '''perinatal asphyxia'''. Other factors predisposing to meconium retention include maternal malnutrition and other conditions that compromise the foal such as dystocia, prematurity, low birth weight, and dehydration.<ref>Semrad, S.D, Shaftoe, S (1992) Gastrointestinal diseases of the neonatal foal. In: Mills, L '''Current Therapy in Equine Medicine''' (Third Edition), W.B. Saunders, Philadelphia. pp 446-447.  In: Pusterla, N, Magdesian, K.G, Maleski, K, Spier, S.J, Madigan, J.E (2004) ''Special Article'': Retrospective evaluation of the use of acetylcysteine enemas in the treatment of meconium retention in foals: 44 cases (1987–2002).  ''Equine Vet Educ'', 16(3):133-136.</ref>  Most impactions are in the small colon at the pelvic inlet, but retention may also occur in the dorsal or transverse colon.<ref name="Pusterla">Pusterla, N, Magdesian, K.G, Maleski, K, Spier, S.J, Madigan, J.E (2004) ''Special Article'': Retrospective evaluation of the use of acetylcysteine enemas in the treatment of meconium retention in foals: 44 cases (1987–2002).  ''Equine Vet Educ'', 16(3):133-136.</ref>

==Clinical Signs==

==Clinical Signs==

==Differential Diagnoses==

==Differential Diagnoses==

*'''Uroperitoneum''': the foal may assume a more extended stance (NB: a ruptured bladder may occur simultaneously with meconium retention)

*'''Uroperitoneum''': the foal may assume a more extended stance (NB: a ruptured bladder may occur simultaneously with meconium retention)

*[[Gastric Ulceration - Horse|Gastrodudodenal ulceration]]

*[[Gastric Ulceration - Horse|Gastrodudodenal ulceration]]

*Impending enteritis

*Impending enteritis

*Obstructive gastrointestinal lesions  

*Obstructive gastrointestinal lesions  

**Small intestinal intussusception

**[[Small Intestine Intussusception - Horse|Small intestinal intussusception]]

**Torsion

**Torsion

**[[Atresia|''Atresia coli'']]

**[[Atresia|''Atresia coli'']]

*'''Enema:''' warm soapy water made with a mild soap that can be administered through soft rubber tubing by gravity.   

*'''Enema:''' warm soapy water made with a mild soap that can be administered through soft rubber tubing by gravity.   

*'''Liquid praffin:''' 300ml by nasogastric tube for foals that do not respond rapidly to an enema

*'''Liquid praffin:''' 300ml by nasogastric tube for foals that do not respond rapidly to an enema

*'''Muzzling and maintenance rate fluids IV:''' for persistent meconium retention resulting in significant abdominal distension. A constant rate infusion of 5-10% dextrose will provide some calories in addition to the free water needs. Dextrose should NOT be given as a bolus.

*'''Muzzling and maintenance rate fluids IV:''' for persistent meconium retention resulting in significant abdominal distension. A constant rate infusion of 5-10% dextrose will provide some calories in addition to the free water needs. Dextrose should NOT be given as a bolus.

*'''Retention enema:''' a more aggressive treatment may be required using acetylcysteine which is an irritant and increases secretion. 20g baking soda and 8g acetylcysteine are added to 200ml water to create a 4% acetylcysteine solution of pH7.6. A 30-french Foley catheter is inserted 2.5 to 5cm into the rectum and the bulb slowly inflated to occlude the rectum. 100-200ml of the solution is adminstered under gravity and retained for 30-45mins by occluding the catheter.<ref>Pusterla, N, Magdesian, K, Maleski, K, ''et al.'' (2004) Retrospective evaluation of the use of acetylcysteine enemas in the treatment of meconium retention in foals: 44 cases (1987-2002).  ''Equine Vet J'', (6):170-174.  In: Wilkins, P.A (2010) 'Diseases Of The Gastrointestinal Tract' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 21.</ref>

*'''Retention enema:''' a more aggressive treatment may be required using acetylcysteine which is an irritant and increases secretion. 20g baking soda and 8g acetylcysteine are added to 200ml water to create a 4% acetylcysteine solution of pH7.6. A 30-french Foley catheter is inserted 2.5 to 5cm into the rectum and the bulb slowly inflated to occlude the rectum. 100-200ml of the solution is administered under gravity and retained for 30-45mins by occluding the catheter.<ref>Pusterla, N, Magdesian, K, Maleski, K, ''et al.'' (2004) Retrospective evaluation of the use of acetylcysteine enemas in the treatment of meconium retention in foals: 44 cases (1987-2002).  ''Equine Vet J'', (6):170-174.  In: Wilkins, P.A (2010) 'Diseases Of The Gastrointestinal Tract' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 21.</ref>

*'''Surgery:''' may be required for extreme cases

*'''Surgery:''' may be required for extreme cases

*'''Analgesia:''' may be needed for some foals. NSAIDs have deleterious effects on renal function and gastric mucosal blood flow, so they should be avoided if possible. '''Butorphanol''' given IM at 0.05 to 0.1mg/kg<ref>Arguedas, M.G, Hines, M.T, Papich, M.G ''et al.'' (2008) Pharmacokinetics of butorphanol and evaluation of physiologic and behavioural effects after intravenous and intramuscular administration to neonatal foals.  ''J Vet Intern Med'', 22(6):1417-1426.  In: Wilkins, P.A (2010) 'Diseases Of The Gastrointestinal Tract' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 21.</ref> may help to prevent straining. '''Hyoscine''' (Buscopan-Boehringer) may alleviate the colic.   

*'''Analgesia:''' may be needed for some foals. NSAIDs have deleterious effects on renal function and gastric mucosal blood flow, so they should be avoided if possible. '''Butorphanol''' given IM <ref>Arguedas, M.G, Hines, M.T, Papich, M.G ''et al.'' (2008) Pharmacokinetics of butorphanol and evaluation of physiologic and behavioural effects after intravenous and intramuscular administration to neonatal foals.  ''J Vet Intern Med'', 22(6):1417-1426.  In: Wilkins, P.A (2010) 'Diseases Of The Gastrointestinal Tract' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 21.</ref> may help to prevent straining. '''Hyoscine''' (Buscopan-Boehringer) may alleviate the colic.   

*'''Intranasal oxygen:''' is useful for foals with significant abdominal distension.<ref>Wilkins, P.A (2004) Respiratory distress in foals with uroperitoneum: possible mechanisms.  ''Equine Vet Educ'', 16(6):293-295.  In: Wilkins, P.A (2010) 'Diseases Of The Gastrointestinal Tract' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 21.</ref>

*'''Intranasal oxygen:''' is useful for foals with significant abdominal distension.<ref>Wilkins, P.A (2004) Respiratory distress in foals with uroperitoneum: possible mechanisms.  ''Equine Vet Educ'', 16(6):293-295.  In: Wilkins, P.A (2010) 'Diseases Of The Gastrointestinal Tract' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), Saunders, Chapter 21.</ref>

==Prognosis==

==Prognosis==

==Complications==

==Complications==

Foals with meconium retention may be at risk of '''sepsis''' because bacterial translocation may occur across the disrupted intestinal mucosa. Blood cultures are thus advisable and foals should be monitored closely for clinical signs of sepsis. Continuous straining may lead to '''patent urachus'''.

[http://www.cabdirect.org/search.html?rowId=1&options1=AND&q1=meconium&occuring1=title&rowId=2&options2=AND&q2=horses&occuring2=od&rowId=3&options3=AND&q3=&occuring3=freetext&x=55&y=15&publishedstart=yyyy&publishedend=yyyy&calendarInput=yyyy-mm-dd&la=any&it=any&show=all Meconium impaction in horses publications]

==References==

==References==

[[Category:Medical_Colic_in_the_Horse]]

[[Category:Medical_Colic_in_the_Horse]]

[[Category:To_Do_-_Nina]]

[[Category:Expert_Review]]

[[Category:To_Do_-_Review]]

[[Category:Colic - Small Colon Causes]]

[[Category:Colic - Small Colon Causes]]

[[Category:Intestine_-_Mechanical_Obstruction]]

[[Category:Intestine_-_Mechanical_Obstruction]]

[[Category:Impaction - Horse]]

[[Category:Impaction - Horse]]

[[Category:Colic - Large Colon Causes]][[Category:Colic - Small Colon Causes]]

[[Category:Colic - Large Colon Causes]][[Category:Colic - Small Colon Causes]]