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Basics ⬇

Outline

BASICS

Definition!!navigator!!

Free hemorrhage within the peritoneal cavity.

Pathophysiology!!navigator!!

Acute Abdominal Hemorrhage

Acute massive blood loss of 30% (≈10–12 L) or more of TBV results in hypovolemic shock. Splenic contraction maintains initial PCV.

Chronic Abdominal Hemorrhage

More than 30% of TBV must be lost before clinical signs become evident. Redistribution of interstitial fluid intravascularly can take up to 24 h, and erythropoiesis is maximal within 1 week. Approximately two-thirds of the erythrocytes from the hemorrhage are autotransfused into the systemic circulation within 24–72 h.

Systems Affected!!navigator!!

Cardiovascular

Hypovolemic shock with massive blood loss.

Urinary

Urine output is decreased because of vasoconstriction.

GI

Colic possible.

Incidence/Prevalence!!navigator!!

Uncommon

Signalment!!navigator!!

Breed Predilections

Arabians and Thoroughbreds.

Mean Age and Range, Predominant Sex

  • Older horses (>13 years)
  • Multiparous broodmares >11 years of age due to reproductive tract bleeding

Signs!!navigator!!

General Comments

Frequently nonspecific. Abdominal discomfort.

Historical Findings

  • Dullness, weakness, depression, and lethargy
  • Anorexia
  • Colic
  • Shock

Physical Examination Findings

Tachycardia, tachypnea, weak peripheral pulses, pale mucous membranes, CRT >2 s, oliguria. Ileus and abdominal distention may be observed.

Causes!!navigator!!

  • Idiopathic
  • Trauma
  • DIC
  • Hemorrhage from the female reproductive tract
    • The ovaries, uterus, or utero-ovarian blood vessels inside or outside the broad ligament
    • Rupture of granulosa cell tumors and from ovarian follicular hematomas
    • Birth-related trauma to the uterine vessels or with uterine neoplasia (leiomyomas or leiomyosarcoma)
  • Hemorrhage from the GI tract
    • Ulcerations
    • NSAID toxicity
    • Rupture of the mesenteric arteries secondary to Strongylus vulgaris larval migration
    • Small strongyles
    • Granulomatous intestinal disease (histoplasmosis, tuberculosis, granulomatous enteritis)
    • Splenic rupture secondary to blunt trauma or neoplasia
    • Entrapment of the small intestine within the epiploic foramen
    • GI vascular leakage secondary to neoplasia or abscessation, coagulopathies, surgery, renal trauma, and hepatic disease
    • Diaphragmatic hernia
    • Phenylephrine administration

Risk Factors!!navigator!!

Age

  • Periparturient hemorrhage most frequently observed in older broodmares (age-related degeneration of the vasculature)
  • Rupture of the caudal vena cava in older horses with epiploic foramen entrapment

Pregnancy

Peripartum hemorrhage can occur before, during, or after foaling.

Blunt External Trauma

Splenic and renal rupture.

Parasitism

Infestation by S. vulgaris, small strongyles.

Diagnosis ⬆ ⬇

Outline

DIAGNOSIS

Differential Diagnosis!!navigator!!

  • All disorders resulting in colic (including other causes of peritonitis)
  • Uterine torsion, uterine rupture, and dystocia in broodmares
  • Disorders resulting in hypovolemic shock

CBC/Biochemistry/Urinalysis!!navigator!!

  • Hematologic abnormalities (decrease in PCV, total red blood cell count, and hemoglobin concentration and hypoproteinemia) will be seen after the initial 24 h due to the physiologic compensatory mechanisms and spleen contraction. Sequential measurement of PCV will be helpful in determining whether the blood loss and resulting anemia are progressive or controlled
  • Coagulation profile reveals thrombocytopenia due to blood loss

Other Laboratory Tests!!navigator!!

Abdominocentesis

  • Hemoperitoneum is definitively diagnosed by abdominocentesis. On cytologic examination, platelets are not typically present unless the hemorrhage is peracute (<45 min) and clotting is not observed
  • The PCV of hemoperitoneum is lower than that of venous blood. In an iatrogenic splenic sample, the PCV will be higher than that of the peripheral blood. On cytologic examination, hypersegmented pyknotic neutrophils and hemosiderophages are observed

Blood Lactate

Blood lactate levels are a more sensitive indicator of early blood loss than PCV. In 1 study, peak lactate concentration was 5.6 ± 7.1 mmol/L.

Blood Gas Analysis

Arterial blood gas analysis can provide useful information about cardiopulmonary function in hypovolemic shock states. It may reveal metabolic acidosis (decreased pH and [HCO3–]) with respiratory compensation (decreased PCO2).

Imaging!!navigator!!

Abdominal US

US evaluation of the abdomen, performed transabdominally or transrectally, reveals homogeneous echogenic “swirling” cellular fluid within the abdomen. The kidneys, liver, and spleen should be examined to identify the origin of the hemorrhage.

Other Diagnostic Procedures!!navigator!!

Rectal Palpation

Fluid accumulation within the abdomen or broad ligament, abnormal (neoplastic) masses, abnormalities within the reproductive tract, or other lesions associated with the site of hemorrhage, and gas-distended intestine may be noted on rectal palpation.

Surgery

May confirm the diagnosis of hemoabdomen and the source of bleeding.

Pathologic Findings!!navigator!!

Necropsy may confirm hemoabdomen.

Treatment ⬆ ⬇

Outline

TREATMENT

Aims!!navigator!!

The primary aims are maintenance of tissue perfusion and oxygenation by restoration of blood volume and hemoglobin and controlling bleeding. The cause and severity of the hypovolemic state are important factors in fluid (crystalloid, colloid, blood products) selection and volume.

Appropriate Health Care!!navigator!!

Rapid action must often be taken to save the life of horses with hemoperitoneum. Most cases will respond favorably to aggressive medical treatment. However, exploratory laparotomy or standing laparoscopy may be needed in patients when the source of bleeding cannot be determined or effectively controlled. Surgery should be performed only when patients are stabilized.

Nursing Care!!navigator!!

Fluid Therapy

  • When hypovolemic shock is present, the condition is addressed by prompt IV therapy with isotonic crystalloid solutions (lactated Ringer's solution, 20–40 mL/kg/h). Replacement fluid volume necessary to maintain perfusion in hemorrhagic shock is usually 2–7 times greater than the actual blood loss. Monitoring is important. Improvement in mentation, jugular distensibility, and CRT, increased pulse strength, and decreased heart rate and increased urine production are indications of improved cardiovascular status
  • Replacement of intravascular volume may also be accomplished with hypertonic saline (5–7.5%, 4 mL/kg) to expand vascular volume, to enhance vascular tone, and to restore intravascular pressure. Contraindicated when bleeding is not controlled
  • Colloids provide volume expansion and oncotic pressure. Use in addition to other types of fluid therapy. Hydroxyethyl starch (hetastarch 6% solution) is given at 10 mL/kg/day infusion. Higher doses can cause coagulation problems

Blood Transfusion

  • Administer when the PCV has rapidly decreased to 15% (0.15 L/L) or the hemoglobin concentration falls below 5 g/dL (50 g/L). Whole-blood transfusion is required to increase oncotic pressure and oxygen-carrying capacity. The volume of blood transfusion will depend on the rate and quantity of blood loss. Whole blood should be administered at 15–25 mL/kg of body weight and repeated if necessary. Balanced crystalloid solutions should be administered concurrently to maintain perfusion
  • Autotransfusion of blood from the abdomen can be life-saving in an exsanguinating horse if no other source of hemoglobin is available. However, it does provide platelets and clotting factors

Activity!!navigator!!

Horses should be strictly rested. Horses surviving a large blood loss should not be exercised for 90 days.

Diet!!navigator!!

N/A

Client Education!!navigator!!

Inform the client that their horse is in danger of cardiac collapse and death.

Surgical Considerations!!navigator!!

Patients not responding to medical treatment and requiring surgical exploration of the abdominal cavity have a low survival rate.

Medications ⬆ ⬇

Outline

MEDICATIONS

Drug(s) of Choice!!navigator!!

Use of procoagulant and antifibrinolytic agents in horses with bleeding disorders is empirical and their efficacy is not proven.

  • Aminocaproic acid—loading dose of 70 mg/kg IV (diluted in 1 L of saline and given over 20 min) followed by a constant rate infusion at 15 mg/kg/h
  • Opioid antagonist (naloxone, 1 treatment of 8 mg IV)
  • 10–30 mL of 10% buffered neutral formalin added to 500 mL of 0.09% NaCl IV

Contraindications!!navigator!!

Phenothiazine tranquilizers (acepromazine) are contraindicated since they decrease blood pressure.

Precautions!!navigator!!

Use α2-agonists (xylazine and detomidine) with extreme caution because they decrease the cardiac output.

Alternative Drugs!!navigator!!

Broad-spectrum antimicrobials, conjugated estrogens, vitamin K, Chinese herb yunnan baiyao, and propranolol have been used anecdotally, but their efficacy has not been demonstrated.

Follow-up ⬆ ⬇

Outline

FOLLOW-UP

Patient Monitoring!!navigator!!

  • Cardiovascular status should be assessed by monitoring mentation, heart rate, pulse strength, CRT, and jugular vein distensibility. From every 5 min to a few times a day depending on whether the hemorrhage is controlled or not
  • Urine output to assess renal blood flow
  • Serial blood lactate measurement can be useful. Lactate concentration should decrease over time if the treatment is successful

Prevention/Avoidance!!navigator!!

Prevention strategies aimed at the different primary causes.

Possible Complications!!navigator!!

  • Cardiovascular collapse and death
  • Bacterial contamination can be a risk during abdominocentesis. US can be more useful to confirm the diagnosis since is a noninvasive method
  • NSAIDs have antiplatelet activity and may lead to renal failure when hypovolemia is present

Expected Course and Prognosis!!navigator!!

  • Overall survival rate is between 50% and 70%
  • Horses with high respiratory rate (>30 breaths/min), neoplasia, mesenteric injury, or DIC are less likely to survive
  • In postparturient broodmares with rupture of the utero-ovarian artery, 2 clinical outcomes are possible depending on whether the hemorrhage is confined in the uterine broad ligament. In the former, a large hematoma develops in the broad ligament and the mare survives. In the latter, death can occur within minutes to days after parturition
  • Horses that survive in the short term have a good prognosis for long-term survival with few complications
  • The prognosis is guarded for a postoperative hemoperitoneum after exploratory celiotomy because of the potential sequelae of septic peritonitis and adhesion formation

Miscellaneous ⬆ ⬇

Outline

MISCELLANEOUS

Age-Related Factors!!navigator!!

Older animals are at risk.

Pregnancy/Fertility/Breeding!!navigator!!

Reasonable prognosis for fertility (50%) for broodmares suffering peripartum hemorrhage.

Synonyms!!navigator!!

Hemoperitoneum

Abbreviations!!navigator!!

  • CRT = capillary refill time
  • DIC = disseminated intravascular coagulopathy
  • GI = gastrointestinal
  • NSAID = non-steroidal anti-inflammatory drug
  • PCO2 = partial pressure of carbon dioxide
  • PCV = packed cell volume
  • TBV = total blood volume
  • US = ultrasonography, ultrasound

Suggested Reading ⬆ ⬇

Conwell RC, Hillyer MH, Mair TS, et al. Haemoperitoneum in horses: a retrospective review of 54 cases. Vet Rec 2010;167:514–518.

Author(s) ⬆

Author: Albert Sole-Guitart

Consulting Editors: Henry Stämpfli and Olimpo Oliver-Espinosa

Acknowledgment: The author and editors acknowledge the prior contribution of Ludovic P. Bouré.