Respiratory Flashcards
Unilateral discharge localisation?
usually = rostral to the nasal septum (nasal passages and sinuses)
Bilateral discharge localisation?
usually = caudal to the nasal septum (guttural pouch, pharynx, larynx, trachea, bronchi and lungs), but sometimes these can present as unilateral discharge
What structure distinguishes URT from LRT?
Upper respiratory tract refers to structures rostral to the larynx.
Lower respiratory tract refers to structures caudal to the larynx.
History for respiratory cases
- Age*, use of horse, ownership
- Onset (sudden* or insidious), duration, progression
- Contact with other horses*
- Other horses affected*
- Management (pasture or stabled, type of feed and bedding**)
- Seasonality**
- Effect of exercise
- Previous / concurrent diseases
*Infectious **Asthma
Clinical signs in respiratory cases
- Unilateral/bilateral (anatomical location)
- Type of discharge (type of disease)
- Swelling, pain, lymph node enlargement (URT)
- Respiratory noise (URT)
- Cough (pharynx/larynx or LRT)
- Exercise tolerance
- Appetite, demeanour
- Respiratory rate and effort (LRT)
Check for other clinical signs, e.g. abortion and neurological disease with Herpes, peripheral oedema with Equine Viral Arteritis, cranial nerve neuropathies with guttural pouch disease
Clinical signs with upper airway disease
- Unilateral or bilateral discharge
- Localising signs to head/pharyngeal region
Submandibular or retropharyngeal lymph node enlargement~
Guttural pouch swelling
Draining tracts
Dental abnormalities
Respiratory noise
+/- Cough
+/- Systemic signs (Strangles, neoplasia)
Clinical signs with lower airway disease
- Cough
- Increased respiratory rate
- Increased respiratory effort
- Increased respiratory noise on auscultation
- Stance and demeanour (pneumonia)
- Exercise intolerance
+/- Systemic signs (Herpes, EVA, pleuropneumonia, neoplasia)
Causes of haemorrhagic nasal discharge
Trauma - injury, foreign body
Causes of mucoid or serous nasal discharge
Viral infection, non infectious inflammatory disease (asthma)
Causes of purulent (no odour) nasal discharge
Bacterial +/- viral infection
Causes of purulent (odourous) nasal discharge
Usually mixed bacteria with anaerobes - check for underlying cause (dental disease, neoplasia, mycosis, foreign body
Causes of food material nasal discharge
Breakdown of pharyngeal anatomy (cleft palate, oral fistula, dental disease)
Choke
Grass sickness
Nasal passages differentials
cleft palate, cysts, polyps, ethmoid haematoma, trauma, foreign body, fungal rhinitis, neoplasia
Sinuses differentials
primary and secondary (inc. dental) bacterial sinusitis, cysts, neoplasia, ethmoid haematoma, trauma, fungal sinusitis, foreign body
Guttural pouch differentials
empyema, mycosis, tympany, trauma, neoplasia
Pharynx/larynx differentials
pharyngitis, URT bacterial or viral disease, arytenoid chondritis, foreign body
LRT differentials
Lung disease: Inflammatory conditions (RAO/Asthma), Infectious conditions (pneumonia, pleuropneumonia, equine influenza, equine herpes virus, equine viral arteritis, Dictylocaulus arnfieldi), neoplasia, exercise induced pulmonary haemorrhage (EIPH)
Diagnosing respiratory disease
History and physical exam +/- oral and neuro exam
Radiography
Endoscopy
Haematology and biochemistry
Infectious disease tests
Lower
Tracheal wash/ BAL
Ultrasonography
Radiography
CT
Aspiration of pleural fluid
When to use radiography for diagnosing respiratory disease
Dental, sinus, guttural pouch disease (bony lesions and fluid lines)
Not for - soft tissues and lower airway disease
Lower
Large masses, fluid lines, small equids
Not for - most diseases, larger horses
When to use endoscopy for diagnosing respiratory disease
Most URT and LRT lesions, inside spaces, soft tissue, and mucosal lesions
Not for - bony lesions, severe epistaxis (red out)
When to use haematology and biochemistry for diagnosing respiratory disease
Infectious processes or systemic involvement
Haematology, fibrinogen, and SAA (serum amyloid A) most useful
What infectious disease tests are there?
Strangles - nasal swab, guttural pouch lavage and serology
Equine influenza - nasal swab and serology
Equine herpes virus - nasal swab, placenta, fetus, serology
Equine viral arteritis - serology, tissue samples
Tracheal wash vs bronchioalveolar lavage (BAL)
Tracheal wash - focal or diffuse disease, poorer cytology, unsedated, easy, no lay off
BAL - diffuse disease only, better cytology, sedation, moderate ease, lay off for 4 days
When to use ultrasound to diagnose respiratory disease
Pleural disease, periphery, surface of lung
Not for - diseases within lung - accoustic shadowing for air
What bacteria causes strangles?
Streptococcus equi equi
Clinical manifestations of strangles
Sudden pyrexia (24 - 48h pre-shedding)
Mucopurulent nasal discharge
RF and SM LN abscessation
Pharyngitis
- Nasal discharge
- Dysphagia
- Cough
- Laryngeal associated pain
- Extended head
Right – moderate lymphoid pharyngeal hyperplasia – inflammation
Can see dorsal displacement of soft palate in severe inflammation with dyspnoea
LN abscessation
- Abscessation 3-14 days after infection
Retropharyngeal – can rupture into guttural pouch
Submandibular
Parotid
Cranial cervical
Can be drained externally
Guttural pouch empyema – pus in body cavity
Complications of strangles
Pneumonia to bronchal pleural fistula
Distant abscesses in different body systems - lymphatic or haematogenous spread
Severe dyspnoea - severe retropharyngeal abscessation, guttural pouch empyema
Immune mediated ascites - uncommon
Type 3 hypersensitivity reaction
Diagnostic testing - acute strangles
History - onset, exposure, travel, new horses?
Clinical signs - variable, non specific, but vital
Endoscopy, US, radiography
Pathogen identification
Culture - 30-40% sensitivity - false negative tests - PCR of nasopharyngeal lavage is optimal - nasopharyngeal swab then nasal swab
Persistent strangles infection
Culture
PCR of endoscopic guttural pouch lavage 3x 7 days apart
Strangles treatment
NSAIDs - pyrexia and pain, inflammation
Soft, calorific diet
Abscess management - hot packing, drainage, lavage
Isolation
Nursing care
Do not lance until mature abscess
GP lavage for empyema
Antibiotics for severe persistent infection - benzylpenicillin
For with severe dyspnoea, dysphagia or persistent fever
Define pneumonia
Bronchopneumonia
Exudative stage
Fibrinopurulent stage
Organisation stage
Infection of lower respiratory tract
Broncho - bronchi and parenchyma
If in pleural space - pleuropneumonia
Exudative stage - sterile transudate in pleural space
Fibrinopurulent stage - bacterial invasion and fibrin deposition
Organisation stage - fibroblasts in exudate - pleural peel
Risk factors for pneumonia
After viral infections
Strenuous exercise
Transportation and prolonged elevation of head - mucocilliary clearance
GA
Overcrowding
Inclement weather
Dysphagia - aspiration
Aspiration pneumonia
Dysphagia - pharyngeal and postpharyngeal
Oesophageal obstruction
GA
Cleft palate
Aitiology of pneumonia
Streptococcus equi zooepidemicus – normal commensal
Staphylococcus aureus and S. pneumonia
Actinobacillus (gram negative non enteric)
Escherichia coli, Pasteurella, Enterobacter, Klebsiella, Bordetella
Bacteroides fragilis
Fusobacterium and Peptostreptococcus anaerobius
Clinical signs of pneumonia
Tachycardia/tachypnoea
Respiratory distress
Fever
Anorexia, depression
+/- nasal discharge
Exercise intolerance
Auscultation – crackles, dull areas – use rebreathing bag to auscultate
Crackles and wheezes
Dull areas
Dull area follows flat line – pleuropneumonia
Pleural ribs – pleuropneumonia
Radiation of cardiac sounds
Pleuro-clinical signs
Pain intercostal spaces – palpate
Reluctance to walk, colic
Grunting during respiration
Abduction of elbows
Ventral oedema
Diagnosis of pneumonia
Physical exam and rebreathing bag
Haematology and biochemistry
Endoscopy
TTW and BAL - hugely useful
- Aerobic and anaerobic (do not refrigerate)
US - white line pleura and surface of lung
- Comet tails - pathology
Radiography
Thoracocentesis
Thoracoscopy
CBC
- Neutrophilia leukocytosis
- Leukopenia
- Anaemia - chronic cases
Increased fibrinogen and SAA
Decreased Fe2+
Pneumonia treatment
Penicillin and Gentamycin IV
Penicillin and Gentamycin and Metronidazole in aspiration pneumonia
Adjust based on C+S
Inhaled drugs
Gentamycin
Ceftiofur
Cefquinome
Equine influenza A
Clinical signs
Diagnosis
Treatment
Infection of respiratory epithelial cells URT, nasopharyngeal shed, destroyed cilia
Clinical signs
- Fever
- Cough
- Nasal discharge - serous, may become purulent - secondary bacterial infection
Diagnosis
- Nasal swab - ELISA, PCR
- Serum - antibodies, ELISA, haemagglutination inhibition -
Treatment
- Nursing care and anti-inflammatories
- Antibiotics for secondary infection
- Vaccine available
Equine herpes virus 1 & 4
Transmission
Clinical signs
Diagnosis
Treatment
Transmission - inhalation of aerosol, contact with infected fomites, reactivation from latency
Infection of respiratory epithelial cells - nasopharyngeal shed
Abortion - rare
Spiral cord - neuro disease - rare
Clinical signs
Common
- Fever, mild cough, slight nasal discharge, poor performance
Occasional - abortion, sick neonatal foal, neurological disease - equine herpes myoencephalopathy - EHM
Diagnosis
- Nasal swab (and placenta/fetus) - PCR
- Blood sample - anticoagulated blood acute
- Antibodies - complement fixation test - serum
Treatment
- Rest in athletic animals
- EHM - nursing care and antiinflammatories
- Vaccine available
Equine viral arteritis
Transmission
Clinical signs
Diagnosis
Treatment
Respiratory, venereal, congenital, fomite spread
URT and LRT, to regional lymph nodes, and replicates into bloodstream
Clinical signs
- Often asymptomatic, fever, nasal discharge, loss of appetite, respiratory distress, skin rash, muscle soreness, conjunctivitis, depression
Relatively rare in UK
Diagnosis
PCR
ELISA for prebreeding or sales
Treatment
Supportive when acute, no treatment for persistent infection in stallions
Vaccine available
Lungworm - Dictocaulus arnfieldi
Transmission
Clinical signs
Diagnosis
Treatment
Parasitic roundworm
Ingestion of L3 larvae from faeces, pasture - donkeys
Mucupurulent exudate, hyperplastic epithelium, lymphocytic infiltrate in lamina propria - alveolitis, brochiolitis, bronchitis
Moderate to severe coughing - exercise
Diagnosis
Larvae in faeces - rarely
Tracheal wash for eggs, larvae and WBC
Failure of antiobiotic therapy, season, history
Treatment
Moxidectin and Ivermectin - stable to treat
LRT risk factors in foals
Systemic sepsis - FPT
Congenital abnormalities
Meconium aspiration
Milk aspiration
Birth trauma
Acute respiratory distress immediately following birth - extrapulmonary disorders causing URT obstruction
Bilateral choanal atresia
Stenosis of nares
Severe laryngeal oedema or collapse
DDSP (dorsal displacement soft palate)
Subepiglottic cyst
Severe pulmonary abnormalities
Congenital cardiac abnormalities
Acute lung injury and acute respiratory distress syndrome - foals
Clinical signs
Treatment
Prognosis
Respiratory failure syndrome - non cardiogenic pulmonary oedema, decreased pulmonary compliance, ventilation/perfusion mismatch
Exaggerated inflammatory response - severe tissue damage
Surfactant deficiency - progressive atelectasis (partial/total lung collapse)
Treatment
- Intranasal oxygen
- Ventilation - mechanical due to lung collapse
- Anti-inflammatories - corticosteroids
- Broad spectrum antibiotics - gentamycin
Poor prognosis
Meconium aspiration foals
Aspirate material from nasal passages and pharynx
Nasotracheal intubation and careful suction
Intranasal oxygen supplementation +/- mechanical ventilation
Anti-inflammatory therapy
Pentoxyfylline - improves circulation
Secondary bacterial pneumonia treatment - broad spectrum - pencillin, gentamicin, TMPS
Milk aspiration foal
Secondary to -
Generalised weakness, poor suckle reflex
Dysphagia - prematurity or neonatal maladjustment
Congenital abnormalities
Diagnosed with history of milk regurgitation
Abnormal lower respiratory sounds
systemic inflammation
pulmonary dysfunction
Endoscopic examination of URT
Thoracic radiography
Treatment
- correct cause of aspiration
- naso-oesophageal feeding tube
- Broad spectrum antimicrobial therapy - TMPS, penicillin, gentamicin
Foal rib fractures
Diagnosis
Treatment
Diagnosis
Physical exam
- Crepitus
- Auscultation - grinding or clicking
Ultrasonography
Treatment
- Conservative
Box rest - avoid pressure on handling
Surgical repair may be necessary if multiple fractures and risk thoracic viscera
Haemothorax - address primary cause of haemorrhage and patient stabilisation and support
Viral pneumonia in foals
Uncommon
EHV1, EHV4, Equine influenza, Equine arteritis, equine adenovirus
Older foals
Dry cough, fever, +/- mucopurulent nasal discharge (secondary bacterial infection)
Usually self limiting
EAV - ventral and limb oedema due to vasculitis
Equine herpes virus in foals
Severe and typically fatal in neonatal foals
Presents similarly to neonatal sepsis
Cardiovascular and respiratory insufficiency
Congested MMs
Leukopenia, neutropenia, lymphopenia
PCR testing of nasal secretions or whole blood
Treatment
Antivirals - Acyclovir, valacyclovir - some efficacy in less affected foals
Supportive care
Parasitic pneumonia foals
Following ingestion of lavated eggs of parascaris - ineffective larvae emerge in intestinal lumen - through liver and lungs - cough up and ingested
Substantial inflammation with migration through lungs
Clinical signs of LRT disease
Usually self limiting
Anthelmintic treatment
- Widespread resistance - treat with pyrantel or fenbendazole
Bacterial pneumonia in foals
Haematogenous spread secondary to bacteraemia or in utero infection. Can be aspiration - milk or meconium
Typically gram negative - e.coli
Most common cause of death in 1-6 month foals
Strep equi zooepidemicus, Rhodococcus equi
Stress of weaning, change in environment
Rhodococcus equi foals
Pneumonia
Gram positive coccibacillus
Ubiquitous
Inhalation
Clinical disease
- Insidious
- LRT infection
- Fever
- Lethargy
- Coughing
- Tachypnoea
- Dyspnoea - nostril flaring and prominent abdominal expiratory effort
Intrapulmonary abscesses
Interstitial or alveolar pattern
Tracheobronchial lymphadenopathy
Pleural effusion
Diagnosis
TTW - cytology and PCR
Oxygen insufflation
NSAIDs
Cool shade
Macrolide and rifampin - azithromycin and clarithromycin
Prevent
Hyperimmune plama
No vaccine yet
Equine asthma
mEA - mild
Age
Clinical signs
Progression
History
Diagnostic confirmation
Young (any age possible)
Clinical signs
- Decrease performance
- No resting dyspnoea
- Occasional cough
- >3 weeks
Spontaneous improvement, response to treatment, no reccurence
History of stabled
Diagnostics
- Endoscopy - tracheal mucous +1 +3
- Cytology - increased neutrophils
- Pulmonary function - 0
Equine asthma
sEA
> 7 year old
Big decrease in perfomance
Frequent cough
Resting dyspnoea
Variable duration
Long term treatment/management/recurrence
History - stabled or pasture, familial history, seasonality
Diagnostics
Treacheal mucus - +1+5
Marked increase neutrophils
Marked effect on pulmonary function
Equine asthma
ARD - airborne respirable dust
Steamed hay
Much more dust from nets
Breathing zone- 30cm from horses nose
Type I and III hypersensitivity
Bronchospasm secondary to inflammation - bronchodilators
Activation of macrophages
Airway neutrophilia
Mucus accumulation
Tissue remodelling
Look for tolerance on rebreathing bag - cough, recovery
Wheezes, crackles, tracheal rattles
Endoscopy - rule out upper airway disease, tracheal mucous - 1h post exercise
BAL - diagnostic of EA
Scant epistaxis - differentials
Foreign body
Fungal granulomas
Neoplasms
Profuse epistaxis differentials
Iatrogenic
Ethmoid haematoma
Trauma - variable
What will we see with nasal cavity bleeding
Rostral to caudal border of nasal septum so usually unilateral
Spontaneous
Highly vascular structures - ethmoid turbinates - so could be profuse
Paranasal sinus epistaxis causes
Trauma
Neoplasia
Ethmoid haematoma
Coagulation disorders
Guttural pouch epistaxis causes
Mycosis - fungal plaques penetrate into carotid artery and erode wall
Foreign body
Neoplasia
Purpura haemolytica
DIC - disseminated intravascular coagulation - very serious overactive clotting proteins
Rectus capitis muscle rupture - fall back and hit back of head - stretch muscle - can fracture base of skull
Bleeding from pharynx, larynx, oral cavity causes
Foreign body
Neoplasia
Purpura
DIC
Clotting defects
Trauma
Iatrogenic
Trachea and lungs bleeding - haemoptysis - causes
Pulmonary haemorrhage - EPIH - exercise induced pulmonary haemorrhage
Trauma
Neoplasia
Foreign body
Iatrogenic
- Lung biopsy
- NG tube
What to do with epistaxis or haemoptysis
History
Evaluation
Treatment
Duration, how many times, colour of blood (mucopurulent, frank), uni/bilateral, associated with exercise, URT disease, recent trauma, toxic plants
Physical exam
- MM, haematomas, prolonged bleeding
- Neuro exam
- Evidence of trauma
- Nasal and flat bones
- Exophthalmos or epiphora
- Symmetry of airflow, stridor
Evaluation of head and resp system
Complete blood count
Clotting profile and platelets - citrate tbe
Biochemical profile - liver enzyme and function tests
Radiography, US
TTW, BAL
Assess blood loss
- No change in PCV with whole blood for 4 hours
- Splenic contraction with hypoxia - increase in PCV
- Fluid from extracellular fluid - decline in TP, decline in PCV 4-6 hours
Determine transfusion need on CS, pathology, history
- Tachypnoea, tachycardia
- Thready or non-palpable pulse quality
- Cool extremities
- Pale MM
- mentation changes - anxiety, depressed, compulsive thirst
- Increased blood lactate - serial measurement increase
- Acute PCV drop >10% or <13%
URT noise -external nares
Epidermal inclusion cysts
Redundant alar folds
Lacerations
Congenital conditions
Wry nose - maxilla deformation - euthanasia
What tooth roots lie in maxillary sinuses?
4th 5th and 6th cheek teeth lie in maxillary sinus
Infection may cause sinusitis
Nasolacrimal canal and infraorbital canal also lie within maxillary sinus
Which cheek tooth forms rostral wall of rostral maxillary sinus
3rd cheek tooth
Infection may cause sinusitis
DDSP - dorsal displacement of soft palate
Treatment
Tie forward - prosthesis replacing thyrohyoid muscle - success rate 80%
What is dynamic pharyngeal collapse?
Collapse of pharyngeal wall when negative pressure highest - maximum inspiration collapse in
Treatment limited
Cleft palate in horses - diagnosis and treatment/prognosis
Nasal reflux of milk/food material and aspiration pneumonia
Endoscopy diagnosis
Poor prognosis - recurrent infections and poor athletic function - euthanasia
Recurrent laryngeal neuropathy
Causes inspiratory stridor with laryngeal muscle paresis - due to recurrent laryngeal nerve paresis
Underlying cause - is it nerve pathology or physical problem - typically idiopathic - left sided hemiplegia
Tie back procedure - physically replicate the dorsal circoaryternodeus - coughing is common side effect as irritation of trachea or aspiration pneumonia as completely open permanently
Arytenoid chondropathy
Inflammation of arytenoid cartilage
Racehorses - inhaled on kicking up
Diagnosis - endoscopy resting - size, mucosa, drainage and granulation tissue, palpation
Treatment
Medical - antimicrobials broad spectrum, antiinflammatories - systemic and local
Sugery
Local excision
Arytenoidectomy
Permanent tracheostomy (esp if bilateral)
Intralaryngeal granulation tissue
Can be concurrent with chondritis and affect prognosis
Excision
Complications - loss of normal anatomy/function
ideally local excision only - laser
Medial deviation of aryepiglottic folds
MDAF - laser to remove excess tissue - high inspiratory negative pressures
Subepiglottic cysts or granulomas
Congenital or acquired
Treat by removal
- Excision through laryngotomy or snare wire
good prognosis
Epiglottic entrapment
Clear distinction from DDSP needed
Typically expiratory noise
Resect transendoscopic laser
