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Canine respiratory disease - Coggle Diagram
Canine respiratory disease
Chronic bronchitis/bronchiectasis
chronic irritation to the bronchial mucosa
increased mucus secretion, compromised respiratory defecnce mechanisms, coughing and bronchoconstriction
the increased presence of mucous and bronchospasm results in narrowing of airways and compromised airflow
airway changes result in chronic coughing, the coughing itself results in repeated damage to the lower airways and perpetuates the inflammatory process
signlament
any breed potentially, often small breed dogs e.g. terriers
history
usually good general condition
cough insidious in onset, dry and hacking
usually unproductive and occurs in paroxysms
often exacerbated by excitement or exercise
pulling on the lead will induce a bout of coughing, as will sudden change in environmental termerature or humidity
clinical exam
may be overweight
harsh increased bronchial sounds with some wheezing audible on auscultation
sinus arrhythmia may be present/exaggerated in some cases
cough easily induced by tracheal palpation
diagnosis
bloods rarely helpful
radiography may show increased bronchial markings, but beware of false positive/false negative results. May reveal bronchiectasis
endoscopy may help confirm dx + rule out other causes of cough
tracheobronchial wash samples reveal a population of mixed inflammatory cells and respiratory epithelial cells
culture is often negative as secondary bacterial contaminants are not always present
treatment
client education essential, unlikely that a cure of the clinical signs will be achieved
changes in patient management are as important as drug therapy
management changes e.g. weight reduction, clean atmosphere, humidification, exercise regime, avoid collar
drug therapy
bronchodilators e.g. theophylline, terbutaline
antibacterial agents - may help if bacterial infection is exacerbating signs but are not consistently indicated
expectorants and mucolytics - may help loosen tenacious secretions
cough suppressants - indicated if coughing is non-productive and compromising animal or owners QoL
anti inflammatory medication
corticosteroids are very effective at suppressing inflammatory response and therefore breaking the vicious cycle in chronic bronchial disease
can be initiated at fairly high doses then tapered to the lowest effective dose regime
1- prednisolone 1mg/kg per os bid for 5 days
2- 0.5mg/kg per os bid for five days
3- then 0.5mg/kg per os every other day
ideally get down to a long term dose in the region of 0.1-0.25mg/kg per os every other day
may be 'too effective' and o wants to stay on indefinitely
makes weight loss more difficult
tracheal collapse
abnormal flexibility of the tracheal rings and stretching of the dorsal ligament of the trachea --> loss of normal rigid cylindrical structure of trachea
dynamic variation in the tracheal diameter
chronic cough and sometimes dyspnoea
history/signalment
typically small breed dogs
yorkshire terrier and minature poodle
chronic coughing - characteristic 'quaking' type of cough due to collapse of trachea during the coughing episodes
physical exam
fairly normal exam
collapse of trachea or larger airways may give rise to audible clicking or slapping noises on inspiration or expiration
if the trachea is very abnormal in outline there may be palpable abnormality of trachea in the cervical region. The edges of the tracheal rings may be palpated
diagnostic investigation
fluoroscopy (no GA required, but not widely available) or endoscopy demonstrate dynamic variation in the trachea
thoracic radiographs may demonstrate variability in the tracheal diameter
the severity of the collapse is graded I-IV according to degree of change of tracheal diameter
treatment
medical management, in effort to reduce clinical signs of coughing, consists of similar measures as outlined to control coughing associated with chronic bronchitis
if clinical signs severe then surgery may be necessary to stabilise the trachea
stenting (external and internal prostheses) have been used to stabilise the tracheal rings
prognosis
mild cases often live happily with persistent cough
signs may progress as tracheal collapse can worsen with age
more severely affected dogs, particularly those with signs of dyspnoea have a guarded prognosis but stunting can help these patients
canine lungworm
types
angiostrongylus vasorum
dilaroides (oslerus) osleri
dirfiliaria immitus (heartworm) not endemic to UK
filaroides Hirthii
crenosome vulpis
history
angiostrongylus affects pulmonary vasculature and may cause pulmonary hypertension and pulmonary haemorrhage
can be associated with the development of systemic coagulopathy and bleeding from any site
filaroides (Oslerus) osleri affects the bifurcation of the trachea and results in signs of airway irritation and coughing
physical exam
no findings specific to disease process
signs of increased respiratory effort and noise may be noted
diagnostic investigation
haematology may show evidence of eosinophilia, blood test of angiostrongylus (index angio detect)
faecal analysis may find larvae but false negatives are common, as not all infections are patent
radiography may show characteristic changes, angiostrongylus vasorum characteristic pattern of involvement reported
nodules at bifurcation of trachea - filaroides osleri
evidence of pulmonary hypertension
angiostrongylus or dirofilaria may cause this sign, but latter not endemic in UK, suspect in imported/travelling dogs
enlargement of main pulmonary artery and tortuous pulmonary arteries
bronchoscopy may show characteristic nodules with filaroides oseleri. May harvest larvae in tracheal washes. May demonstrate evidence of eosinophilic inflammation
treatment
5-7 day course of Fenbendazole (Panacur) at dose of 50mg/kg
Agents specifically licensed for use in treatment of angiostrongylus include 'Advocate' containing Moxidecting and 'Milbemax' containing Milbemycin
prognosis
many cases of parasitic pneumonia can be completely cured with appropriate treatment
may take many weeks for clinical signs to subside completely due to the inflammatory reaction that takes place within the pulmonary parenchyma secondary to the killed parasites