Equine Epistaxis Lecture Review

Predict Potential Sources of Epistaxis: Develop in-depth understanding of the clinical characteristics and anatomical considerations of epistaxis to accurately determine its potential origins.
Formulate Diagnostic Plans: Create comprehensive and tailored diagnostic strategies for evaluating equine cases of epistaxis, incorporating advanced diagnostic tools and methodologies.
Evaluate Blood Component Therapy: Critically analyze the indications for, and timing of, blood component therapy in managing equine patients experiencing epistaxis, taking into account the underlying causes and severity of blood loss.

Definition: Epistaxis, commonly known as a nosebleed, refers to the presence of blood at the external nares (nostrils) and is a common clinical finding in equine medicine. It can vary significantly in severity and underlying causes.
Haemoptysis: While epistaxis is localized to the nasal area, haemoptysis involves coughing up blood from the lower respiratory tract. It is essential to differentiate these conditions during diagnosis as they may stem from different pathologies.
Severity: The volume of blood loss may range from small flecks at the nostrils to significant hemorrhage that requires immediate veterinary intervention. Understanding the volume and appearance of blood is crucial for assessing the urgency of treatment.

Nasal Cavity: A primary location for potential bleeding sources including vascular lesions or traumatic injury.
Paranasal Sinuses: These spaces can harbor conditions such as sinusitis or tumors that may lead to bleeding into the nasal cavity.
Guttural Pouches: Positioned lateral to the pharynx, guttural pouches are major sites for various conditions (infections, tumors) that can result in epistaxis.
Oral Cavity, Pharynx, Larynx, Trachea, Lungs: Other anatomical structures that may contribute to epistaxis, necessitating a thorough examination to exclude these areas as sources of bleeding.

Characteristics:
Rostral to caudal: The location from which the bleeding arises within the nasal cavity can provide insights into the source, as different areas are associated with specific conditions.
Unilateral: Epistaxis is often unilateral and may assist in narrowing down the source; bleeding generally occurs from one nostril rather than bilaterally.
Spontaneous appearance: Blood may appear suddenly, sometimes without any preceding signs or symptoms, indicating the need for immediate assessment.
Types of Bleeding:
Scant Sources:
- Foreign bodies: Items lodged in the nasal passages can lead to localized irritation and bleeding.
- Fungal granulomas: These can result from fungal infections that cause inflammation and damage to the nasal mucosa.
- Neoplasms: Tumors of the nasal cavity can present as localized bleeding and often require imaging for diagnosis.
Profuse Sources:
- Iatrogenic causes: Injuries resulting from procedures or treatments such as nasogastric tube placement.
- Ethmoid haematoma: A localized, often hemorrhagic mass that can cause significant nasal bleeding, typically requiring surgical intervention.
- Variable trauma: Trauma to the head or face may lead to extensive nasal bleeding and needs careful assessment.

Potential Causes:
Trauma: Damage to the sinus areas can lead to hemorrhage.
Neoplasia: Tumors can invade the vascular structures of the sinuses, leading to bleeding.
Ethmoid haematoma: Similar to nasal cavity considerations but emphasizes the peculiarities and commonality of these lesions in equines.
Coagulation disorders: Conditions affecting blood coagulation can manifest as epistaxis from the sinuses as well.

Common Pathologies:
Mycosis: Fungal infections that erode the vascular walls, leading to hemorrhage.
Foreign body obstruction: Obstruction can lead to inflammation and subsequent bleeding.
Neoplasia: Tumors affecting the pouches can lead to significant bleeding challenges.
Purpura hemorrhagica: An immunological condition that can involve multiple systems and lead to epistaxis.
Disseminated Intravascular Coagulation (DIC): A serious condition leading to widespread clotting and bleeding abnormalities, necessitating urgent care.
Other clotting defects: These can lead to complications such as rectus capitis muscle rupture due to bleeding in the neck region.

Initial Steps:
History Gathering: A thorough history is critical, including assessment of the duration, frequency, volume and color of blood; inquire about exercise-related bleeding, concurrent signs of respiratory disease, trauma history, and any medications administration.
Physical Examination: Conducting a comprehensive physical examination focusing on the oral cavity and nostrils, as well as assessing the head and respiratory system is vital.
Examination Components:
- Observing mucous membranes, presence of haematomas, and signs of prolonged bleeding.
- A neuro exam to identify any signs of trauma to the head, neck, and thorax.
- Assess nasal airflow and symmetry; check also for signs of stridor indicating respiratory distress.
Laboratory Tests:
Complete CBC (Complete Blood Count) and clotting profile should be run if indicated, assessing for anemia or other hematological issues.
Check the biochemistry profile for liver function and enzyme levels which can inform on coagulation potential.
Consider advanced diagnostics such as endoscopy for visual assessment, radiographic and ultrasonographic examinations for structural assessment, and may require tracheal washes (TTW) and bronchoalveolar lavage (BAL) for further evaluation and diagnosis.

Acute Blood Loss Effects:
Immediate shedding of red blood cells (RBC), white blood cells (WBC), protein, and significant overall volume loss can complicate assessment.
Note that PCV (Packed Cell Volume) and TP (Total Protein) may not demonstrate changes for the first four hours post-bleeding because of compensatory mechanisms.
In response to hypoxia, splenic contraction may occur, resulting in increased PCV after blood loss which can obscure the actual volume lost.
Rapid fluid shifts can lead to altered Total Protein (TP) and PCV levels within hours due to equilibration between intravascular and interstitial compartments.

Criteria for Urgency:
Rapid blood loss necessitates quicker interventions—understanding the importance of timely transfusion and intervention may save lives.
No single criteria exist for transfusion eligibility; rather, a combination of clinical signs, laboratory findings, historical context, and clinician experience should guide the decision.
Clinical Signs (CS) to Watch For:
Signs of Shock: Identifying tachycardia, tachypnoea, cool extremities, and altered mental state (anxiety, depression) are essential markers indicating severe blood loss.
Laboratory Indicators: Elevated blood lactate levels, and significant drops in PCV (greater than 10% or PCV below 13%) serve as red flags for impending shock.