epistaxis in horses

Question 1

what are the potential causes of epistaxis in horses?

Answer 1

• nasal cavity
• paranasal sinuses
• guttural pouch
• oral cavity
• pharynx
• larynx
• trachea
• lungs

Question 2

what is the apperance and causes of nasal cavity origin epistaxis in horses?

Answer 2

• Unilateral (usually)

Scant bleeding:
* Foreign bodies
* Fungal granulomas
* Neoplasms

Profuse bleeding:
* Iatrogenic (eg during endoscopy)
* Ethmoid haematoma - relatively common, growth form the ethmoid into nasal cavity or paranasal sinus
* Trauma (variable)

Question 3

what is the apperance and causes of paranasal sinuses origin epistaxis in horses?

Answer 3

usually unilateral
* Trauma
* Neoplasia
* Ethmoid haematoma
* Coagulation disorders

Question 4

what are the causes of guttural pouch origin epistaxis in horses?

Answer 4

• Mycosis - fungal plaques erode the walls of the arteries
• Foreign body
• Neoplasia
• Purpura hemorrhagica
  ◦ secondary to a streptococcal or viral respiratory tract infection. It’s an immune-mediated vasculitis that can cause petechial hemorrhages (small spots of bleeding)
• DIC
• Other clotting defects
• Rectus capitis muscle rupture

Question 5

what are the causes of epistaxis from the pharynx, larynx and oral cavity?

Answer 5

• Foreign body
• Neoplasia
• Purpura
• DIC
• Other clotting defects
• Trauma
• Iatrogenic

Question 6

what are the tracheal and lung causes of epistaxis in horses?

Answer 6

• Pulmonary haemorrhage
  ◦ exercise-induced pulmonary haemorrhage - EIPH
• Trauma
• Pneumonia
• Neoplasia
• Foreign body
• Iatrogenic
  ◦ Lung biopsy
  ◦ NG tube

Question 7

describe the full diagnostic plan for epistaxis in horses?

Answer 7

• History
  ◦ Duration, number of times, volume, colour of blood, one or both nostrils, associated to exercise?, URT disease, Recent trauma, toxic plants…
• Complete PE & oral and nares examination
• Evaluation of head and respiratory system
  ◦ MM, haematomas, prolonged bleeding
  ◦ Neuro exam
  ◦ Evidence of trauma, head, neck, thorax
  ◦ Nasal & flat bones
  ◦ Exophthalmos or epiphora
  ◦ Symmetry of airflow nares, stridor
• Complete CBC
• Clotting profile & platelets (citrate tube) if CS suggestive
  ◦ (PT, APTT, FDPs, AT-III)
• Biochemistry profile
  ◦ (Liver enzymes & liver function tests)
• Endoscopy
• Radiographic & ultrasonographic examination
• TTW & BAL

Question 8

what are the issues with trying to assess acute blood loss in horses?

Answer 8

with Acute blood loss:
◦ Loss of RBC, WBC, Protein & Volume
‣ No change in PCV or TP in first 4 hours
◦ Splenic contraction in response to hypoxia
‣ Increase in PCV
◦ Fluid recruited from Extracellular fluid
‣ Decline in TP without decline on PCV– possible decline in PCV 4-6h
* PCV changes not appreciated for 12-24 hrs

Question 9

what calcuation can be done to asses whether a horse needs a transfusion?

Answer 9

Calculating O2 Extraction rate (ER):
* normal horse 30% ER
* with acute blood loss, tissue become hypoxic so will extract more oxygen from the blood, 50-60% ER is concerning

Question 10

what are the clinical signs that indicate a trasfusion might be needed in horses?

Answer 10

• Tachycardia & tachypnoea
  ◦ Higher rate > urgent
• ↓ pulse quality
  ◦ Thready or non-palpable
• Cool extremities
• Pale MM
• Mentation changes (anxiety, depressed, compulsive thirst)
• ↑ Blood lactate (serial measurements) (due to hypoxic tissues anaerobic resp)
• ↓ PCV (acute drop 10% (in 12-24h) or PCV < 13%