Respiratory System Flashcards
RES01-06
start of RES01
name the 2 channels that make up the nostril
- nasal diverticulum (dorsal)
- true nostril (ventral)
what is the fold that separates the nasald diverticulum from the true nostril
alar fold
how many major nasal conchae are contained in each nasal cavity
2 (dorsal and ventral)
dorsal and ventral conhae contain distinct, air-filled structures known as this
bullae
(ventral conchal bulla (VCB) and DCB)
where does the dorsal and ventral conchal bullae (DCB and VCB) sit in relation to the paranasal sinuses
rostral
these are scroll-like plates of bone in the caudal nasal cavity
ethmoid turbinates
how many pairs of paranasal sinuses are there?
7 pairs
name the 7 pairs of paranasal sinuses
- rostral maxillary sinus
- caudal maxillary sinus
- dorsal conchal sinus
- ventral conchal sinus
- frontal sinus
- ethmoidal sinus
- sphenopalatine sinus
alveoli of maxillary Triadan 08-11 protrude into which sinuses?
rostral and caudal maxillary sinuses
name the 5 most common clinical signs of nasal and sinus disorders
- purulent unilateral nasal discharge
- unilaterally enlarged submandibular LN
- reduced nasal airflow
- facial swelling
- epistaxis
paralysis of what nerve can cause nostril paralysis and be a rare cause of airflow obstruction
facial nerve
this is a dynamic condition, only occurring during exercise;
collaps into nasal cavity, causing airflow obstruction and abnormal resp noise (‘buzzing’ noise)
alar fold collapse
this is a cyst structure lined by keratinised or non-keratinised squamous epithelium, with no sebaceous element;
develop in false nostril, resulting in facial swelling at nasomaxillary arch;
do NOT cause nasal airflow obstructions
epidermal inclusion cyst
this is a rare congenital craniofacial deformity with deformity of the nasal, premaxillary and even maxillary bones;
can disturb nasal airflow and result in malocclusions of the incisors;
variety of surgical and orthodontic treatments available;
should have routine odontoplasty at least every 6mo
wry nose
this is a slow expanding, non-neoplastic mass most commonly originating from ethmoid labyrinth;
recurrent haemorrhage of resp submucos, possibly due to chronic infection
progressive ethmoid haematoma (PEH)
what is the most common clinical sign of progressive ethmoid haematoma (PEH)
unilateral, intermittent low-volume epistaxis
how to diagnose progressive ethmoid haematoma (PEH)
mass with distinct red-green or yellow-green capsule seen during endoscopy
name 2 treatments for progressive ethmoid haematoma (PEH)
- transendoscopic chemical ablation with 10% formalin injected intralesionally
- surgical removal
name 5 conditions that could lead to secondary sinusitis
- dental disease
- paranasal sinus cyst
- progressive ethmoid haematoma
- trauma
- neoplasia
this is an expansive, fluid-filled mass that originates from sinus mucosa;
progressive expansion can result in facial swelling, exophthalmos, epiphora and distortion of the nasal cavity, reducing airflow
paranasal sinus cyst
how to treat paranasal sinus cyst
surgical removal of cyst
what 2 bones are typically involved in facial fractures?
- nasal
- frontal
what is the most common neoplasia of the nasal cavity
squamous cell carcinoma
name 3 advantages of performing sinus surgery as standing procedure
- reduces cost
- eliminates risk associated with GA
- better visualisation (decr haemorrhage)
name the term for surgically creating a hole into select paranasal sinuses
trephined osteotomy
name the sinus surgery
3-sided bone flap either into the frontal sinus (most common) or maxillary sinuses;
used for treatment of extensive disorders within the paranasal sinuses
osteoplastic flaps
start of RES02
these are air-filled, mucosa-lined outpouchings of the auditory tubes connecting the nasopharynx to the middle ear
guttural pouches
what is the approximate volume of the guttural pouches
350mL
each guttural pouch is separated into a medial and lateral compartment by what bone?
stylohyoid bone
name the guttural pouch compartment
contains:
external carotid, maxillary artery, superficial temporal arteries;
cranial nerves: facial nerve (VII), mandibular
lateral compartment
name the guttural pouch compartment
contains:
internal carotid, cranial sympathetic nerves, cranial cervical ganglion, pharyngeal nerve plexus, cranial laryngeal nerve;
neck “strap muscles” - long capitus muscle;
cranial nerves: gloddopharyngeal (IX), vagus (X), accessory (XI), hypoglossal (XII)
medial compartment
name 4 common presenting signs of guttural pouch disease (relates to the structures affected)
- epistaxis
- nasal discharge
- nerve dysfunction
- swelling/dyspnoea
dysfunction of what 2 nerves due to guttural pouch disease could cause dysphagia
- pharyngeal branch of vagus n.
- glossopharyngeal
name 3 clinical signs of Horners syndrome
(could be due to guttural pouch disease)
- ptosis
- miosis
- patchy sweating
name the guttural pouch disease
primary fungal plaque (Aspergillus spp) forms over vessels (most commonly the internal carotid);
relatively uncommon;
potentially life threatening;
MUST rule out in horses with epistaxis
guttural pouch mycosis (GPM)
name 3 clinical signs of guttural pouch mycosis (GPM)
- nasal discharge
- epistaxis
- +/- nerve dysfunction
how to treat guttural pouch mycosis (GPM)
surgical occlusion of the affected artery
(simple ligation)
why does the artery affected by guttural pouch mycosis (GPM) need to be occluded on both sides?
circle of willis
(can bleed on both sides - back flow)
name the guttural pouch disease
purulent material or chondroids (inspissated purulent material) within one or both guttural pouches;
usually occurs in young horses;
due to URT with strangles OR abscesses in lymph nodes
guttural pouch empyaema
name 5 clinical signs of guttural pouch empyaema/chondroids
- intermittent nasal discharge
- parotid swelling and pain
- extended head carriage
- respiratory noise at rest
- difficulty swallowing and eating
name 3 treatment options for guttural pouch empyaema/chondroids
- flushing of pouches with catheters via ostia
- endoscopic removal of chondroids
- surgical flushing and removal (less common now)
name the guttural pouch disease
gas distension of the guttural pouch;
occurs in foals;
failure of pressure normalisation usually due to congenital defect in ostia or neurological dysfunction;
often unilateral;
confirmed on radiography or endoscopy
guttural pouch tympany
name 3 clinical signs of guttural pouch tympany
- marked retropharyngeal swelling
- respiratory stridor
- dysphagia
what is the medical treatment for guttural pouch tympany
place foley catheter in ostia - leave in situ attached to nostril
what is the surgical treatment for guttural pouch tympany
fenestration between pouches - one functional ostia
name the guttural pouch disease
progressive disease of the middle ear and bones of the temporohyoid joint (stylohyoid bone & squamous portion of the temporal bone)
temporohyoid osteoarthropathy
name 4 early clinical signs of temporohyoid osteoarthropathy
- head shaking
- ear rubbing
- behavioural change
- resentment of ridden exercise
name 3 chronic clinical signs of temporohyoid osteoarthropathy
- facial nerve paralysis
- head tilt and ataxia
- nystagmus (slow toward affected side)
name the guttural pouch disease
caused by trauma usually due to rearing and falling over backwards;
profuse bilateral epistaxis, ataxia, head tilt, pharyngeal & tracheal compression and 2nd upper airway obstruction
rupture of neck “strap muscle”
name the 3 muscles making up the neck “strap muscles”
- longus capitus muscle
- rectus capitus ventralis muscle
- rectus capitus lateralis muscle
how to diagnose most guttural pouch diseases?
endoscopy
what are the 2 main functions of the pharynx
- delivers air from the nasal cavity to the larynx
- provides a pathway for food to be passed from the oral cavity to the oesophagus
what separates the nasopharynx from the oropharynx
soft palate
where does the larynx sit
in the nasopharynx
(apart from during swallowing)
name 6 common clinical signs seen with conditions of the pharynx
- poor performance
- resp noise
- dysphagia
- nasal discharge
- coughing
- resp distress
what is the most common condition of the pharynx?
dorsal displacement of the soft palate (DDSP)
name the condition of the pharynx
dynamic condition that occurs during intense exercise;
results in an expiratory obstruction;
following exercise returns to normal position;
no other evidence of pharyngeal dysfunction
intermittent dorsal displacement of the soft palate (IDDSP)
name the condition of the pharynx
soft palate is permanently displaced;
frequently secondary to other disease;
may have dysphagia
persistent dorsal displacement of the soft palate (DDSP)
name 3 clinical signs of dorsal displacement of the soft palate (DDSP)
- exercise intolerance
- gurgling/vibrating noise
- rider reports ‘choking down/up’ / ‘swallowing its tongue’
what is the proposed pathogenesis of intermittent dorsal displacement of the soft palate (IDDSP)
neuromuscular pathogenesis
(of pharyngeal branch of vagus nerve)
name 4 conservative treatments for intermittent dorsal displacement of the soft palate (IDDSP)
- get horses fit
- change tack - change noseband/bit to keep mouth closed
- tongue tie to stop caudal movement of tongue
- treat inflammatory conditions of the pharynx/GP
name 4 surgical treatments of dorsal displacement of the soft palate (DDSP)
- staphylectomy
- myectomy - sternothyroid
- induction of palatal fibrosis
- tie forward
name 2 differential diagnoses for milk at the nostril of a foal
- guttural pouch tympany
- cleft palate
start of RES03
name the 3 main functions of the larynx
- breathing
- protect lower airway
- phonation/vocalisation
name the 4 cartilages that support the larynx
- cricoid cartilage
- thyroid cartilage
- epiglottis
- paired arytenoid cartilage
name 5 clinical signs seen with conditions of the larynx
- resp noise
- poor performance
- dysphagia
- coughing
- resp distress
name the larynx disease
occurs in horses from a few months of age to 10y old;
most commonly affects larger breeds;
Hx of abnormal inspiratory noise at exercise and poor performance
recurrent laryngeal neuropathy (RLN)
what 3 aspects of the larynx does the Havemeyer scale assess?
used at rest to aid in objective assessment
- synchrony of movement
- ability to achieve full abduction
- ability to maintain full abduction
what is the gold standard to assess degree of collapse during exercise?
dynamic endoscopy
name the Havemeyer Scale grade
all arytenoid cartilage movements are synchronous and symmetrical and full arytenoid abduction can be achieved and maintained
grade 1
name the Havemeyer Scale grade
arytenoid cartilage movements are asynchronous and/or larynx asymmetric are seen at times but full arytenoid abduction can be achieved and maintained
grade 2
name the Havemeyer Scale grade
arytenoid cartilage movements are asynchronous and/or asymmetric;
full arytenoid cartilage abduction cannot be achieved and maintained
grade 3
name the Havemeyer Scale grade
complete immobility of the arytenoid cartilage and vocal fold
grade 4
name 3 treatment options for recurrent laryngeal neuropathy (RLN)
- ventriculectomy/ventriculocordectomy
- laryngoplasty
- re-innervation
name the recurrent laryngeal neuropathy (RLN) treatment
‘Hobday’ procedure;
performed via a laryngotomy under GA (or standing);
roaring burr used to evert both ventricles;
ventricle then exised +/- vocal cord removed at same time
ventriculectomy / ventriculocordectomy
name the recurrent laryngeal neuropathy (RLN) treatment
suture placed between dorsocaudal edge of cricoid cartilage and muscular process of left arytenoid cartilage;
mimics the action of CAD;
permanent abduction of L arytenoid cartilage
prosthetic laryngoplasty
(‘tie back’)
name 5 possible complications with prosthetic laryngoplasty
- failure
- dysphagia
- aspiration
- persistent cough
- infection
name the recurrent laryngeal neuropathy (RLN) treatment
C1 nerve graft: innervates omohyoideus, accessory muscle of respiration;
implanted into CAD muscle belly
laryngeal re-innervation
name 5 causes of laryngeal paralysis
- recurrent laryngeal neuropathy (RLN)
- peripheral neuropathy (liver disease)
- guttural pouch disease
- organophosphate poisoning
- injection of irritant drugs
name 4 differential diagnoses for right sided laryngeal paralysis
- 4 BAD (4th brachial arch defect)
- perivascular injection
- GP mycosis
- previous surgery
name 4 differential diagnoses for bilateral laryngeal paralysis
- hepatic disease
- toxicity (organophosphate, lead)
- post-anaesthetic
- EPM (Equine Protozoal Myeloencephalitis)
name the cause of right-sided laryngeal paralysis
variable development of R laryngeal cartilage;
rostral displacement of palatopharyngeal arch;
R sided asymmetry;
variable ability to abduct arytenoid
4-BAD (4th brachial arch defect)
name the laryngeal disease
mucosal ulceration;
infection of arytenoid cartilage;
progressive;
resp obstruction: younger thorough breds and older mares
arytenoid chondroitis
name 4 indications for a tracheotomy
- emergency bypass of URT obstruction
- route for intubation
- rest the URT
- bypass inoperable URT obstruction
where should the incision be made for an emergency tracheotomy
on the ventral midline at the junction btwn upper and middle third of the neck
(6-8cm)
name the 7 basic steps of an emergency tracheotomy
- clip
- palpate sternohyoideus muscles and tracheal rings
- 10mL local anaesthetic
- 6-8cm incision at junction btwn upper and middle third of neck
- stab incision between 2 tracheal rings
- extend for 1-2cm each side of midline incision
- insert tracheotomy tube
start of RES04
what is the oxygen requirement during racing
50-80 L/min
what tracheal secretion volume score is associated with poor exercise performance
2+
what 2 things is the tracheal secretion score dependent on?
- rate of production of secretions
- rate of clearance of secretions
name 4 benefits of thoracic ultrasonography
- non-invasive
- real time images
- suitable for field use
- equipment readily available and inexpensive
name 2 limitations of thoracic ultrasonography
- cannot image axial pulmonary lesions that lie deep to aerated lung
- cannot image mediastinum
name the ultrasound artefact
healthy lung;
equidistant, parallel, horizontal lines;
reverberation artefacts
A lines
name the ultrasound sign
vertical lines,
sub-pleural pathology;
consolidation, inflammatory cells, mucus, blood, pus, oedema, small masses
B lines
what is a tracheal aspirate (TA) with neutrophilia >20% associated with?
cough
what is a BALF with neutrophilia >5% associated with
poor athletic performance
name 4 causes of eosinophilia >2% in BALF or TA
- eosinophilic sub-type of MMEA and SEA
- lungworm
- Parascaris equorum migration
- idipathic pulmonary eosinophilia
name 2 cells that might be seen in BALF with the following conditions:
1. EIPH
2. trauma during sample collection
3. neoplasia, abscesses, coagulopathy (rarely)
erythrocytes and haemosiderophages
name 2 ways to take lung biopsies
- trans-endoscopic pinch biopsy
- percutaneous biopsy (rarely indicated)
name 5 differential diagnoses for neonatal pulmonary disease
- neonatal bacterial pneumonia
- fractured ribs
- meconium aspiration
- prepartum EHV-1 infection
- prematurity/dysmaturity
.
name 6 ancillary diagnostic techniques for neonatal pneumonia
- quantify serum IgG
- bronchoscopy
- bacterial culture
- thoracic radiography
- u/s
- haematology & acute phase proteins
name 4 treatments for neonatal pneumonia
- plasma (IgG) transfusion
- broad spectrum abx (cephalosporins)
- intranasal oxygen
- intensive nursing
what is the best way to diagnose rib fractures?
ultrasonography
name 2 causes of bacterial respiratory disease in older foals & weanlings
- Rhodococcus equi
- Streptococcus equi var zooepidemicus
name the cause of pneumonia in older foals and weanlings
group problem on intensive studs;
2-6mo of age;
inhalation of bacteria in soil dust;
multiple abscesses develop slowly throughout pulmonary parenchyma
Rhodococcus equi pneumonia
name 5 clinical signs of Rhodococcus equi pneumonia
- wasting/ill-thrift
- pyrexia
- resp difficulty > coughing > nasal discharge
- abnormal auscultation
- extra-pulmonary signs = diarrhoea, polysynovitis
name 5 ways to diagnose Rhodococcus equi pneumonia
- u/s
- radiography
- culture resp secretions
- R. equi VapA serum ELISA
- haematology + serum amyloid A
what 2 abx can be used to treat Rhodococcus equi pneumonia
- doxycycline for 6-8wks
- Rifampin & azithromycin
name 3 viruses causing outbreaks of acute, infectious resp disease in adults
- influenza
- EHV-1
- EHV-4
what bacteria is the most common cause of outbreaks of acute infectious resp disease in adutls
Strangles
(Streptococcus equi var equi)
how is equine viral arteritis spread?
venereal + respiratory secretions
name 5 sequelae of Strangles
- lymph node abscesses
- GP empyema
- ‘bastard strangles’
- immune-mediated vasculitis
- immune-mediated haemolytic anaemia
name 5 parts of treatment for Strangles
- isolation
- rest
- NSAIDs
- feed from floor
- lance abscess
start of RES06
what is the most common chronic respiratory disease in horses >5y old
Severe equine asthma
(recurrent airway obstruction, heaves, broken wind, COPD)
name 4 bronchodilators that can be used to treat severe equine asthma
- atropine IV
- Buscopan IV (hyoscine)
- Clenbuterol IV & PO
- inhaled salbutamol
what is the best ‘rescue’ drug for severe equine asthma?
can be used for single dose, otherwise causes ileus and tachycardia
atropine
(bronchodilator)
name the bronchodilator
low therapeutic index,
only effective in some horses (~25%);
inflammation downregulates B2 receptors;
tachyphylaxis >12d
Clenbuterol
name 2 inhaled glucocorticoids that can be used to treat severe equine asthma
- beclomethasone
- fluticasone
name the treatment for summer severe equine asthma
- atropine then beta2 agonist
- corticosteroids
this is a non-septic airway disease in athletic horses;
likely reflects a clinical syndrome with variable aetiology and consequences (bacteria/viruses, dust, immunosuppressive factors);
high incidence
mild to moderate equine asthma (MMEA)
(Inflammatory Airway Disease, IAD)
name 5 clinical signs of mild to moderate equine asthma (MMEA)
- cough
- nasal discharge
- accumulation of mucopus in trachea
- TA neutrophilia
- poor exercise performance
name 4 treatments of mild to moderate equine asthma (MMEA)
- rest
- dust-free environment
- abx (oxytet, doxy, TMPS)
- inhaled glucocorticoids
name 4 clinical signs of pulmonary oedema
- frothy nasal discharge (+/- blood-tinged)
- inspiratory crackles
- restrictive lung dysfunction
- endoscopy (frothy fluid in airways)
what does multiple, evenly distributed, ring down artifacts without associated pleural irregularities seen on ultrasound of lungs suggest?
pulmonary oedema
name 3 treatments for pulmonary oedema
- furosemide
- salbutamol aerosol
- intranasal O2
name 4 risk factors for bacterial pneumonia in adult horses
(otherwise rare)
- aspiration
- transport
- glucocorticoid therapy
- neoplasia
name 5 causes of pleural effusions
- thoracic neoplasia
- bacterial pleuropneumonia
- penetrating chest wall wounds
- congestive heart failure
- hypoproteinaemia
name 4 causes of pneumothorax
- penetrating chest wall wounds
- fractured ribs
- spread of subcutaneous emphysema from wounds of axilla and neck
- oesophageal penetration
how to treat non-dyspnoeic horses with pneumothorax
rest
4 parts of treatment for dyspnoeic horses with pneumothorax
- close wounds
- thoracocentesis
- intranasal O2
- analgesia
this is caused by pulmonary capillary rupture;
almost all horses have this during high speed exercise;
uncommon in endurance and draught horses;
increases with age;
epistaxis rare
exercise induced pulmonary haemorrhage (EIPH)
how to diagnose exercise induced pulmonary haemorrhage (EIPH)
endoscopy 30-120min post-exercise
(blood visible for 1-3d)
name 5 ways to manage exercise induced pulmonary haemorrhage (EIPH)
- optimise air hygiene
- treat airway disease (URT and LRT)
- treat atrial fibrillation
- nasal dilator strips
- rest if severe
