L27: Ruminant Respiratory Dz (MacKay) Flashcards
PE of resp. System
- visual inspection
- airflow
- palpation
- auscultation
- percussion
Advanced diagnostics for resp. System
- endoscopy
- nasal swabs
- nasopharyngeal swabs
- TTW
- BAL
- rads
- US
Most commonly used infectious dz testin
PCR
Stridor vs. stertor
Stridor: generated by larynx/trachea, high pitched; can be inspiratory or expiratory
Stertor: like snoring, low pitched vibration of nasopharyngeal soft tissues; always inspiratory
Adventitial sounds
Crackles
Wheezes
Pleural friction rubs
*very seldom heard
Loud bronchial sounds assoc. with:
ventral bronchopneumonia
Breathing is normally costoabdominal
Transitions to abdominal only if diseased
CS of upper resp. Tract diseases
-inspiratory dyspnea (stridor or stertor)
-open mouth breathing + tongue protrusion
-head extension
+/- nasal d/c, lymphadenopathy, cough
CONGENITAL upper resp. Tract diseases
Pharyngeal or sinus cyst Cystic nasal turbinates Skull anomalies Laryngeal anomalies Tracheal collapse
ACQUIRED upper resp. Tract dz of ruminants
FB Trauma/fracture Tumors (LSA) Abscess (larynx, pharynx) Actinobacillosis/Actinomycosis Fungal granuloma Necrotic laryngitis Sinusitis Allergic rhinitis Tracheal edema Tracheal collapse
Upper respiratory diseases
- allergic rhinitis
- pharyngeal trauma
- calf diphtheria (oral necrobacillosis, necrotic laryngitis)
- sinusitis
- tracheal edema syndrome
Allergic rhinitis (aka Summer Snuffles, Chronic granular rhinitis)
- Type I hypersensitivity rxn to plant pollen or fungal spores
- common in pastured cattle in spring/summer
- Channel Island and Holstein predisposed
- 6 mo. To 2 yr. old cattle usually
CS, Dx, Tx of summer snuffles
CS: BAR, profuse bilateral mucoid nasal d/c, nasal pruritus, sneezing, head shaking, resp. Stertor, mouth breathing
Dx: CS, dx of exclusion, cytology of nasal washes has eos
Tx: nothing, prevent exposure, steroids/antihistamines
Mycotic nasal granulomas
- several fungi reported (Rhinosporidium, Aspergillus, Conidiobolus)
- no age/breed/seasonal predilection
- progressive mucopurulent nasal d/c +/- epistaxis, stertor
Dx/Tx of mycotic nasal granulomas
Dx: endoscopy, biopsy and culture +/- PCR
Tx: sx removal, sodium iodide, antifungal agents?
Causes of pharyngeal trauma
Balling/drenching guns
Wires
Rough stemmy feeds
Grass awns
Common bacteria assoc. with pharyngeal trauma
- Trueperella pyogenes**
- Actinobacillus spp.
- Pasteurella spp
- Bordetella spp
- Fusobacterium necrophorum
CS of pharyngeal trauma infection
Fever Pain during swallowing Quidding or reluctance to eat solids Mucopurulent nasal d/c +/- halitosis Pharyngeal swelling Resp. Distress Toxemia Drooling
Dx/Tx of pharyngeal trauma
Dx:
- manual exam
- rads
- US
- endoscopy
Tx:
- drainage of pharynx (externally)
- tracheotomy if severe
- abx, NSAIDs
- supportive therapy
Calf diphtheria (aka necrotic laryngitis/oral necrobacillosis) in different aged calves
1) calves 1-4 mo. get infection of soft tissue of oral cavity
- spreads from common utensils or licking
2) calves 3-18 months that are on feed for >30 days** get infection of laryngeal mucosa and cartilage
- sporadic incidence with more cases in fall and winter
- more common in crowded dirty conditions and feedlots
Pathophys. Of calf diphtheria
- Mucosal injury to oral cavity from tooth eruption OR
- inflammation of URT or laryngeal mucosa from viral infections and coughing leading to laryngeal contact ulcers —-> invasion of bacteria
- Fusobacterium necrophorum and Trueperella most common
CS of calf diphtheria
-hypersalivation, reluctance to eat
-fever, depression, hyperemic membranes
+/- abscess in cheek region
-laryngitis –> painful cough, severe inspiratory dyspnea with stridor and open mouth breathing –> eventual obstruction
Dx/Tx of calf diphtheria
Dx based on CS, endoscopy
Tx:
- penicillin, ceftiofur
- NSAIDs
- tracheotomy
- arytenoidectomy
- supportive care
- fair to poor prog.
Causes of sinusitis and which sinus are they in?
- dehorning (frontal, common)
- tooth root abscess (maxillary)
- other: viral, trauma, neoplasia, actinomycosis
CS of sinusitis
- nasal d/c +/- halitosis
- anorexia, lethargy, fever
- bone distortion, obstructed air flow
- erosion of bone and meningitis in neglected cases
- 2ary neuro signs
3 things that can cause neuro signs 2ary to sinusitis***
1) invasion through cribiform plate into venous sinuses
2) formation of pituitary abscess
3) formation of subdural abscess
Do maxillary and dorsal conchal sinuses communicate with frontal sinus?
No
Dx/Tx of sinusitis
Dx: CS, percussion, aspiration of sinuses, rads, endoscopy
Tx: lavage and systemic abx +/- trephination, tooth repulsion and/or tooth extraction
-penicillin usually sufficient
Tracheal edema syndrome
- causes edema and hemorrhage in the wall of the trachea
- kills most of the cattle it effects (due to obstruction of the trachea)
- cattle make honking noise before they die
- has acute dyspnea and chronic cough forms
Acute dyspnea form of tracheal edema syndrome
- more common in southern feedlots
- causes acute onset dyspnea, stridor, sudden death in
Chronic form of tracheal edema syndrome
- more common in western feedlots
- unthrifty, with only occasional deaths
- affects caudal 1/3 of trachea
Viral respiratory diseases of cattle
1) infectious bovine rhinotracheitis virus (BHV1)* - most common
2) bovine respiratroy syncytial virus (BRSV)*
3) bovine viral diarrhea virus (BVDV)
4) parainfluenza virus type 3 (PIV-3)
5) coronavirus (BCoV)*
6) BHV*
7) MCF*
8) adenovirus
9) rhinovirus, reovirus, enterovirus
- = known to cause death (although rarely)
MCF caused by what viruses
OHV2, AHV1
Transmission of viral respiratory diseases
Direct contact or aerosol
Etiology of viral resp. Dz in beef and dairy cattle
Beef:
- more common after arrival at feedlots or stocker/backgrounding operations
- disease in suckling calves poorly characterized
Dairy:
- calves up to 6 months of age** (enzootic pneumonia)
- sporadic in adults
*have short incubation period, highly contagious
CS/Dx of viral respiratory dz
CS: fever, nasal d/c, cough, malaise
Dx: PCR most common; virus isolation, Ag detection, serology
Immunosuppression caused by viral resp. Dz effects:
*innate, and some acquired immunity of the lung:
- nasopharyngeal lymphoid tissues
- ciliated tracheobronchial epi cells
- Tracheobronchial macs
- T lymphs
Which respiratory viruses have synergism with Mannheimia?
BHV1
BRSV
PI3
BVDV
Bovine herpesviruses and what they cause
BoHV-1 –> infectious bovine rhinotracheitis (IBR), infectious pustular vulvovaginitis and balanoposthitis
BoHV-2 –> bovine herpes mammilitis
BoHV-3 –> bovine cytomegalovirus
BoHV-4 –> mild resp. Dz; mammary pustular dermatitis
BoHV-5 –> neuro dz in calves
CS of IBR
- fever, nasal d/c, cough, tachypnea
- reduced appetite, ptyalism, decreased milk production
- conjunctivitis, corneal opacities
- pustules, diphteric plaques
- hyperemia of muzzle (“rednose”)
- abortion
- 2ary bacterial infection
Infectious Bovine Rhinotracheitis pathogenesis
- URT epithelial infection
- low-level viremia
- latency in trigeminal ganglia
- droplet spreads up to 4m
- causes necrotic rhinolaryngotracheitis +/- repro mucosa
- CS not pathognomonic
Vaccination for IBR
- “core” vax
- MLV-IM causes rapid lifelong immunity
- MLV-IN safe in pregnant cows, calves
- killed virus vaccine is cheap but requires booster
Bovine respiratory syncytial virus (BRSV) etiology
- RNA virus
- syncytial cell formation
- affects goats and sheep too
- causes mild, widespread explosive outbreaks
- puts at risk for enzootic pneumonia
- has short incubation period and long shedding period
Functional Anatomy of lungs
- well demarcated lung lobes with robust interlobular septa
- small total alveolar SA
- extensive lymphatic drainage, so pleural effusion is rare
- tracheobronchus serves cranial lobes
- left lobes: apical and cardiac
- right lobes: apical, intermediate, cardiac, accessory, diaphragmatic
