Reproductive emergencies in the mare (Proceedings)

Occurrence

• Breeding

o Rectal tears

• Palpation

• Penetration by stallion

o Vaginal tears

• Penetration by stallion

• Peri-parturient

o Dystocia

o Hemorrhage

o Uterine

• Torsion

• Prolapse

• Rupture / tear

• Retained fetal membranes

• Metritis

o Vagina

• Rectovaginal tears

o Gastro-intestinal

• Damage to viscera

• Rectal prolapse

Breeding associated emergencies

• Rectal tears

o Associated with:

• Palpation

• Penile penetration of rectum by stallion

o Signs

• "Feeling" of release of rectal tissue around arm

• Blood on sleeve or penis

• Onset of shock

• Signs of peritonitis

• Usually colic

• Straining to defecate

o Types

• Grade 1

• Involves only rectal mucosa and submucosa

• Grade 2

• Through muscular layer

• Mucosa and submucosa intact

• No bleeding

• Forms diverticulum

• Grade 3a

• Only serosal layer is intact

• Grade 3b

• Occurs dorsally

• Mesorectum and retroperitoneal tissues are intact

• Grade 4

• All layers disrupted

• Fecal contamination of peritoneum

o Incidence

• Most occur dorsally

• 15 – 55 cm from the anus

• In one retrospective study of 85 horses with rectal tears (Eastman TG et al Equine Vet Edu 2000 12(5):263-266.)

• 4⅞ 5 associated with routine pregnancy exams

• Grade 1 - 93% survived to discharge

• Grade 2 – 66% (2/3) survived to discharge

• Grade 3a – 70%

• Grade 3b – 69%

• Grade 4 – 6%

• Few cases of penile penetration in literature

• 2 at MDS-EMC in last 5 years

• Both lateral wall

• Grade 3b

• Both survived

o First-aid for rectal tears

• Exam of tear

• Sedation

• Buscopan

• Careful palpation

• Remove feces

• Pack rectum

• 20 cm cranial to tear

• Close anus

• Epidural

• Transportation concerns

• Antibiotics

• Broad spectrum

• Penicillin (potassium or sodium penicillin 22,000 IU; IV)

• Gentamicin – 6.6 mg/kg IV

• Metronidazole – 15 mg/kg PO

• Flunixin meglumine – 1.1 mg/kg IV

• Tube with oil

• IV fluids

• If in shock

• Withhold food

• Refer for evaluation

• Vaginal tears

o Occur during intromission

o Uncommon

o Mild to severe trauma to vagina

o Vaginal rupture

• Usually adjacent to cervix

• Dorsolateral

• Can also affect lateral wall of vestibule

• Semen is not sterile

• Results in peritonitis

• Evisceration (Tulleners EP et al JAVMA 1985 186(4): 385-7)

o Partial thickness

• Peri-vaginal abscessation if not identified acutely

o Signs

• Vaginal bleeding

• Colic

• Minutes to hours post-breeding

• Straining

• Peritonitis (signs)

• Fever

• Depression

• Lethargy

o First aid for vaginal rupture

• Broad spectrum antibiotics

• Peritonitis

• Flunixin meglumine

• If evisceration:

• Reduce and pack with sterile soaked towels

• Large enough so they won't pass into the abdomen through the tear

• Close vulva

o Clamps or suture closed

• Treat shock

• Refer for medical and surgical treatment

Peri-parturient emergencies

• Dystocia

o Epidemiology

• 4% Thoroughbreds (McKinnon and Voss Equine Reproduction 1993 pp 578)

• 10% Draft breeds (McKinnon and Voss Equine Reproduction 1993 pp 578)

• 10% Miniature horses

o Signs

• Colic in term mare with other signs of imminent parturition

• No amnion visualized after 5 minutes in Stage 2 labor

• No foal after rupture of chorioallantois

• One hoof but no further progress despite abdominal contractions of mare

• Nose is presented first

• See the ventral portion of the foot

• Nothing palpable in vagina despite signs of active labor

o Types of malposition

• Anterior presentation

• Head and neck reflection

• Limb malposture

• Foot-nape posture

• Rotated

o Dorsal, lateral, ventral

• Posterior presentation

• Transverse presentation

o Treatment

• Assisted vaginal delivery

• Sedation

• Epidural

• Lubrication

• Controlled vaginal delivery

• Anesthesia

• Hindquarters elevated

• Lubrication

• Fetotomy

• Cesarean section

• Referred for surgery

• Time is of the essence for foal survival!

• In a large retrospective study of 247 horses (Byron et al EVJ 2002 35(1):82-85)

• Time from chorioallantoic rupture to delivery

o Foals survived to discharge = 71.7 min ± 34.3 min

o Non-survivors = 85.3 ± 37.4 min

o 42% of foals delivered alive

o 29% survived to discharge

o 91% of mares discharged

o Treatment

• Except for fetotomy there is no effect of method of delivery on** +

o Mare survival

o Mare fertility

• Peri-parturient hemorrhage

• Older, multiparous mares

• Most common cause of death in older foaling mares

• When?

o At parturition

o Post-partum (24-48 hours)

o Pre-partum

• Where?

o Middle uterine artery

o Utero-ovarian artery

o External iliac artery

• Why?

o Degenerate process in arterial wall (Rooney JR. Cornell Vet 1964)

o Low serum copper levels (Stowe HD J Nutr 1968)

o Predisposing factors (McCarthy PF Equine Pract 1994)

• Large foal

• Assisted delivery

• Retrospective studies (Rooney. Cornell Vet 1964)

o 10 mares

• 2/10 died at 7 months of gestation

• 8/10 died at foaling

• 3/10 ruptured left utero-ovarian artery

• 7/10 ruptured right utero-ovarian/middle uterine/ external iliac artery

• Histology

• Degeneration of the internal elastic lamina

• Intimal fibrosis

• Thickening and accumulation of metachromatic, mucoid material in the intima and media at aneurysm site

• —> Lesions are related to the aging process!

• 13 mares (Pascoe RR. Vet Rec 1979)

• Group 1 - 8 mares

o 6/8 mares - death within 30 min to 20 hours postpartum

o 2/8 mares - death 3 days/25 days postpartum (ruptured the hematoma)

o ⅞ rupture of right ovarian or utero-ovarian artery

• Group 2 – 5 mares

o No clinical signs

o 5/5 hematoma in right broad ligament

o 1 died at parturition due to acute hemorrhage

o ¼ re-bred after hematoma resolved (died postpartum)

o ¾ palpable masses in broad ligament- not re-bred

• Signs

o Colic

o Sweating

o Pale mucous membranes

o Rapid pulse

o Anemia

o Intra-peritoneal

• Rapid deterioration

• Acute shock signs

o More subtle signs if hemorrhage is contained in broad ligament

• Diagnosis

o History

o Clinical signs

o Physical examination

o Hematology

o Transabdominal ultrasound

o Abdominocentesis

o Transrectal palpation/ultrasound

• Treatment

o Prevent activity/excitement

o Quiet, dark environment

o Warmth

o Sedation (acepromazine)

o Keep foal close by-if possible/safe

• If not-foal requires support

o Plasma expansion therapy

• Crystalloids (hypertonic saline, LRS)

• Colloids (Hetastarch, plasma)

• Whole blood transfusion

• Blood substitutes (Oxyglobin)

o Oxygen supplementation via nasal insufflation

o Antifibrinolytic drugs (aminocaproic acid, tranexamic acid)

o Anti-inflammatory drugs

o Glucocorticoids (prednisolone sodium succinate)

o Analgesic drugs

• Opioids (butorphanol)

• Anesthetics (lidocaine)

o Broad-spectrum antibiotics

o Anti-oxidant drugs (DMSO, Vitamin E/selenium)

o Oxytocin – low dose therapy for uterine involution

• Prognosis for survival

o Depends on severity and location of hemorrhage

o Worse if intra-abdominal hemorrhage present

• Prognosis for future fertility

o Rebreeding unsuccessful unless hematoma in broad ligament resolves

• Recurrence

o High risk with future breeding/foaling

• Uterine Torsion

o Incidence 5-10% of all serious equine obstetric problems

• Less frequent than in cows but greater difficulty in resolving the torsion and lower survival rate in horses

o Underlying cause unknown

o Contributing factors:

• Vigorous fetal movement

• Sudden falls

• Large fetus in small fluid volume

• Lack of tone in the pregnant uterus

o Signs

• Colic

• Restlessness

• Sweating

• Anorexia

• Frequent urination, sawhorse stance

• Looking at flank, kicking at abdomen

• TPR – normal to slightly elevated

o Complications

• Restriction of blood flow through uterine and utero-ovarian arteries

• Arterial rupture and fatal hemorrhage

• Thrombosis of large uterine arteries and veins (common)

• Rupture of the vessel

o Diagnosis:

• Physical examination

• Transrectal palpation

• Broad ligaments are tense and spiraling in the direction of the torsion

• Clockwise vs. counterclockwise

• Small colon might be constricted by torsion and impede ability to perform complete rectal palpation

• Determine viability of fetus, integrity of uterus and direction of torsion

• Vaginal examination – often not helpful

o Treatment

• Nonsurgical

• Mare is term and cervix is dilated —> manual detorsion and assisted delivery

• Mare is preterm and cervix is closed/vagina or cervix are involved —> Rolling of anesthetized mare

• Risks:

o Uterine rupture

o Risk of placental detachment

o Abortion

o Fetal/maternal death

o Recurrence of uterine torsion during same pregnancy

• Surgical

• Flank laparotomy

• Ventral midline approach (at term gestation)

• Risks:

o Premature placental separation

o Uterine wall necrosis, uterine tearing

o Peritonitis

o Partial or complete dehiscence of incision

o Recurrence of torsion during same pregnancy

o Prognosis

• Mare survival rate 84% (Chaney KP et al. AAEP proceedings 2006)

• 97% <10 mo gestation

• 65% >10 mo gestation

• 67% successfully rebred

• Foal survival rate 54%

• 72% <10 mo gestation

• 32% >10mo gestation

• Surgical management 73% survival rate (Pascoe RR et al. JAVMA 1981)

• Nonsurgical management 85% survival rate (Wichtel JJ et al. JAVMA 1988)

• Uterine rupture

o Associated with:

• Fetotomy

• Excessive manipulation during dystocia

• Fetal malposition

• Uterine torsion

• Uterine lavage

• Normal delivery

o Complications:

• Visceral herniation

• Peritonitis

• Hemorrhage

• Shock

• Death

o Most common site:

• Dorsal aspect of uterus

o Clinical signs (Dolente BA. Critical peripartum disease in the mare. Vet Clin Equine 2004)

• Anorexia

• Fever, malaise

• Tachycardia, tachypnea

• Ileus, colic

• Dehydration

• Signs of diffuse, severe, septic peritonitis

• Hypovolemic shock

• Signs may not be evident until 24-48 hours after parturition

o Diagnosis

• Can be challenging

• Abdominocentesis

• Transrectal palpation

• Palpation of the uterine lumen

• Laparoscopy

• Exploratory celiotomy

o Treatment

• Conservative management

• Successful if tear is small, on dorsal aspect of uterus, minimal hemorrhage, no uterine therapy required

• Supportive therapy

• Treat shock and peritonitis

• Cross-tying to prevent abdominal herniation through tear

• Surgical management

• Ventral midline celiotomy

• Flank approach

• Supportive therapy

• Antibiotics

• NSAIDs

• IV fluids

• Abdominal lavage

• Adhesion prevention (heparin, etc)

• Oxytocin

• Laxatives

o Prognosis

• Variable

• Uterine prolapse

o Less likely than in cows due to cranial attachments of uterus

o Associated with:

• Normal delivery – uncommon

• Abortion (8-10 months gestation)

• Prolonged parturition/dystocia

• Retained placenta

• Old age

• May occur several hours after fetal delivery

o Complications:

• Retained fetal membranes

• Uterine rupture

• Bladder eversion/prolapse

• Intestinal herniation/rectal prolapse

o Clinical signs (Perkins NR, Frazer GS. Vet Clin North Am Equine Pract 1994)

• Mild to moderate tenesmus

• Restlessness, pain

• Anxiety, anorexia

• Tachycardia, tachypnea

• Hypovolemic/endotoxic shock esp. if excessive bleeding or incarceration of intestines present

• Rapid weak pulse, rapid shallow respiration

• Pale mucous membranes

• Depression, prostration, rapid death

o Diagnosis

• Presence of prolapsed organ hanging from vagina

o Treatment:

• Sedation and analgesia

• Lavage and examination of the uterus

• Gentle replacement of the uterus

• If uterus is edematous:

• Compression of the uterus with bandage before replacement

• Complete reduction must be performed!

• Placement of vulvar retention sutures/Caslick's

• Supportive therapy (incl. intrauterine therapy, laxatives)

o Prognosis

• Good

• Future fertility

• Depends on degree of endometrial damage during the prolapse

• Recurrence rate

• Unknown

• Considered to be low

• Retained fetal membranes

o Failure of passage of part, or all, of the chorioallantoic membrane within a specific time period of fetal delivery (3 hours)

o Most common post partum complication

o Incidence of RFM 2-10%

o Most common site - tip of the non-gravid horn

• Microcotyledons more deeply interdigitated

• Edematous tip of gravid horn more squashed and stunted

o Predisposing factors

• Mechanical interference with normal expulsion

• Hormonal imbalances

o Complications

• Severe metritis

• Septicemia/Endotoxemia

• Laminitis

o Clinical signs

• Portion of fetal membranes protruding through vulvar lips

• Retention may occur without any membrane appearance

• Vaginal discharge

• Fever

• Anorexia

• Depression

• Laminitis

o Treatment

• Tetanus prophylaxis

• Oxytocin (10-40 IU)

• Stimulate separation of microcotyledons from endometrium

• Distention of chorioallantoic sac with 5-15L saline and ligation to contain fluid in it

• Tying of protruding placental remnants in knot above the mare's hocks

• Tying a weight to protruding fetal membranes

• Manual removal of RFM

• Correct calcium imbalance

• Controlled exercise

• Systemic treatment

• Antibiotics

• NSAIDs

• Uterine lavage

• Uterine infusion with antibiotics (oxytetracycline)

• Septic metritis

o Sequelae of retained fetal membranes

o Following dystocia:

• Greater risk of toxic metritis and laminitis

o Delayed uterine involution

o Increased autolysis of the placenta

o Severe bacterial infection

o Diagnosis

• Rectal examination

• Large, thin walled uterus

• Flaccid tone

• Moderate to large amount of intraluminal fluid

• Transrectal ultrasound

o Complications (Blanchard T et al. Comp Cont Educ Pract Vet 1990

• Septicemia

• Endotoxemia

• Laminitis

o Treatment

• Antibiotics

• NSAIDs

• IV fluid therapy

• Large volume uterine lavage

• Uterine infusion with antibiotics

• Oxytocin

• Controlled exercise

• Laminitis prevention

• Recto-vaginal tears

o Three grades

o Although they can look severe acutely immediate surgery is rarely necessary

o Treat symptomatically

• NSAIDS

• Antibiotics

o Metritis

• Chronic

o Incontinence

• Occasionally

• Gastro-intestinal related emergencies

o Bowel rupture

• Cecal/colonic rupture

• Most common gastrointestinal catastrophe associated with parturition (Rossdale 1994)

o After normal parturition or dystocia

o Occasionally before parturition

o Why?

• Trauma during delivery

• Focal necrosis of intestinal wall

• Thromboembolism

• Tapeworms

• NSAID administration

o Clinical signs

• Acute abdominal pain

• Septic shock

o Results in

• Peritoneal contamination

• Severe peritonitis

• Profound endotoxemia

• Death within 24 hours

o Diagnosis

• Physical examination

• Abdominocentesis

• Transrectal palpation

• Roughened peritoneal surface

• Pneumoperitoneum

o Treatment

• Euthanasia

o Trauma to small colon/small intestine

• Injury to

• Bowel wall

• Mesocolon/mesojejunum

• Ischemic necrosis of colon/jejunum

• Associated with

• Normal parturition

• Dystocia

• +/- type III or IV rectal prolapse

• Clinical signs

• Depression

• Moderate to severe colic

• Absence of fecal passage

• Febrile

• Decreased gastrointestinal motility, gastric reflux

• Diagnosis

• Physical examination

• Rectal examination

o May be non-specific

• Abdominocentesis

o Septic/non-septic peritonitis

• Laparoscopy

• Exploratory celiotomy

• Treatment

• Resection and anastomosis

• Colostomy

• Prognosis

• Variable (36% small colon)

• Rectal prolapse1

o Due to prolonged or forceful tenesmus

o Parturition/dystocia

o Rectal mucosa is apparent

o Variable degree of inflammation, cyanosis, trauma, necrosis

o 4 types

• Type I – only rectal mucosa involved

• Type II – complete prolapse of rectal ampulla

• Type I and II – usually no signs of colic

• Type III – prolapse of rectum with evagination of descending colon

• Type IV – prolapse of descending colon or rectal intussusception (associated with dystocia in mares)

• Type III and IV may be associated with tearing of the mesocolon, avascular necrosis of descending colon – may result in abdominal pain

o Diagnosis

• Examination and palpation of prolapsed tissue

• Abdominocentesis

o Treatment

• Epidural anesthesia

• Manual reduction

• Reduce edema

• Application of glycerin, dextrose

• Placement of purse string suture

• Administration of laxatives

• Laparoscopy

• Ventral midline celiotomy

o Prognosis

• Depends on viability of small colon and rectum