Lungworm Flashcards
Outline the life cycle of lungworm
Dog consumes L3
Matures to L5 in the dog, produces new larvae L1
Eggs contain larvae that hatch and cross into the alveoli and are carried to the pharynx and swallowed,
These are coughed up, swallowed, passed in the f+
Mature to L3 in intermediate host
What is the PPP of lungworm?
31-65 days
This mean pets can have severe disease but not shed in f+
What is the most common clinical sign?
Cough - but not present in all
What pathology in the lungs does lungworm cause
Granulomatous interstitial pneumonia, often in the periphery
Can get concurrent bacterial infection
Pulmonary fibrosis, more common with high load, not reversable
Pulmonary haemorrhage
Pleural space disease - haemothorax and pneumothorax
What can you see on x-rays?
patchy alveolar interstitial pattern an be more diffuse/ fixed Can be diffuse broncho interstitial Pleural fissure lines Can get peripheral nodules Pulmonary hypertension
What can you see on CT?
increase lung attenuation and tracheobronchial lymphadenopathy
non specific findings
What may you see on rads with pulmonary hypertension
may be normal
May see enlargement of Pulmonary artery or right hand side of the heart (D)
What can you see on U/S with pulmonary hypertension
Tricuspid / pulmonic regurge RV dilation/ hypertrophy Septal flattening in systole Dilation of pulmonary artery Decrease in LV diameter
When can pulmonary hypertension occur?
at diagnosis, immediately post treatment, weeks later
What is the importance of pulmonary hypertension?
Think of it in pets that aren’t doing well
collapsing, exercise intolerance
Poorer px if have PH
approx 5% in GP
What are the possible mechanisms for the coagulation problems associated with lungworm?
Hyperfibrinolysis DIC Inhibition of coagulation IMTP acquired wvf deficiency accumulation of immune complexes
What do clotting bloods look like?
Variable - clotting times not reliable
Common to see low fibrinogen
How do you treat any hyperfibrinogenaemia?
+++ FFP - oft more than one transfusion
Tranexamic acid
What causes any neuro signs?
H+
verminous meningitis
or both
Can cause pretty much any neuro sign
How useful is faecal analysis in dx?
baermanns, <50%
Faecal smear - good spec but poor sens
Issues can be - assessed before PPP, intermittent shedding, poor sample quality, poor testing skills, low larval numbers, can take 8 hours
How useful is the angiodetect
Reported numbers are sens 98%, spec 96%, although likely a little less,
Can get false -ves from if tested too early
Where do adult worms live?
Adult parasites are located in the right side of the heart
and the pulmonary arterial circulation
Can be found in small arteries in the periphery of the lungs
What coag test results do you see with DIC?
Prothrombin time (PT) Increase or normal
Activated partial thromboplastin time Increase (often before the PT)
Fibrinogen Mild decrease (consumptive)
Fibrin degradation products Increase (positive test result)
D-dimers Increase (positive test result)
Platelets Mild decrease (consumptive)
What lab abnormalities may be found?
Eosinophilia in 50% patients
High protein in 75%
May see evidence of DIC
Sometimes (rare) see hypercalcaemia, anaemia
How do you treat lungworm?
Imidacloprid/moxidectin or milbemycin are licenced
Can also use fenbendazole
How can you treat any respiratory signs?
02
Can try AI doses of steroids although v limited evidence
Where does C vulpis reside?
URT
N/B life cycle is very similar to A vasorum
What are the clinical signs of c vulpis lungworm?
cough
possible nasal dicharge
What is the life cycle of filaroides osleri?
direct life cycle and L1 are thought to be mainly
transmitted from a bitch to its pups in the sputum
What are the clinical signs of filaroides osleri?
present with chronic respiratory signs: mild
to severe inspiratory sounds or wheezing, dyspnoea and/or coughing, which is often harsh in nature and accompanied by retching. As such, these dogs may be misdiagnosed as having infectious tracheobronchitis or ‘kennel cough’.
How do you diagnose filaroides osleri?
A definitive diagnosis is made by finding larvae on faecal Baermann or zinc sulfate flotation examination. Larvae and eggs may also be seen in the sputum or tracheal wash fluid. Patients may also have a positive tracheal pinch test and radiographs may demonstrate tracheal thickening with ill-defined soft tissue densities within the trachea; a tracheoscopy is very useful to visualise these nodules.
How do you treat filaroides osleri?
Fenbendazole is the licensed preparation for treatment of F osleri. Efficacy is demonstrated by the absence of clinical signs, a negative faecal analysis and resolution of nodules on repeat tracheoscopy/bronchoscopy, although it can take several weeks for any nodules to resolve fully
How does toxocara canis cause signs in pups?
Toxocara canis undergoes hepatotracheal migration after larvated eggs have been ingested, and transplacentally transmitted larvae accumulate in the lungs until birth.
In both situations, respiratory signs can ensue and are
most severe in pups soon after birth, when larvae in the
lungs mobilise synchronously and can cause pulmonary damage, which is evident as coughing, dyspnoea and sometimes nasal discharge. Respiratory signs are only present in very heavy infections. Larvae transmitted to the pup via milk do not migrate via the lungs.
Where is Aelurostrongylus abstrusus found?
lung parenchyma and bronchioles, within nodules.
What are the clinical signs of Aelurostrongylus abstrusus?
may be asymptomatic or present with mild to severe respiratory disease, which is caused by an inflammatory response to the presence of the parasite . Features can include coughing, wheezing, sneezing, nasal discharge, dyspnoea and tachypnoea.
Anorexia is present in some cases and, occasionally,
pulmonary hypertension can lead to death. most cases are of mild to moderate severity
How do you diagnose Aelurostrongylus abstrusus?
On rads, Combinations of alveolar, bronchial and interstitial patterns are reported. Young cats (often less than one year of age) tend to have an alveolar pattern. Miliary interstitial densities and vascular pathology are also reported
A definitive diagnosis is made when L1 are found in either faeces or BAL fluid, although, as with all of the above parasites, their absence does not necessarily rule out disease.
How do you treat Aelurostrongylus abstrusus?
Fenbendazole and low dose of prednisolone
