Lungworm

Question 1

Outline the life cycle of lungworm

Answer 1

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

Question 2

What is the PPP of lungworm?

Answer 2

31-65 days

This mean pets can have severe disease but not shed in f+

Question 3

What is the most common clinical sign?

Answer 3

Cough - but not present in all

Question 4

What pathology in the lungs does lungworm cause

Answer 4

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

Question 5

What can you see on x-rays?

Answer 5

patchy alveolar interstitial pattern
an be more diffuse/ fixed
Can be diffuse broncho interstitial
Pleural fissure lines
Can get peripheral nodules
Pulmonary hypertension

Question 6

What can you see on CT?

Answer 6

increase lung attenuation and tracheobronchial lymphadenopathy
non specific findings

Question 7

What may you see on rads with pulmonary hypertension

Answer 7

may be normal

May see enlargement of Pulmonary artery or right hand side of the heart (D)

Question 8

What can you see on U/S with pulmonary hypertension

Answer 8

Tricuspid / pulmonic regurge
RV dilation/ hypertrophy
Septal flattening in systole
Dilation of pulmonary artery
Decrease in LV diameter

Question 9

When can pulmonary hypertension occur?

Answer 9

at diagnosis, immediately post treatment, weeks later

Question 10

What is the importance of pulmonary hypertension?

Answer 10

Think of it in pets that aren’t doing well
collapsing, exercise intolerance
Poorer px if have PH
approx 5% in GP

Question 11

What are the possible mechanisms for the coagulation problems associated with lungworm?

Answer 11

Hyperfibrinolysis
DIC
Inhibition of coagulation
IMTP
acquired wvf deficiency
accumulation of immune complexes

Question 12

What do clotting bloods look like?

Answer 12

Variable - clotting times not reliable

Common to see low fibrinogen

Question 13

How do you treat any hyperfibrinogenaemia?

Answer 13

+++ FFP - oft more than one transfusion

Tranexamic acid

Question 14

What causes any neuro signs?

Answer 14

H+
verminous meningitis
or both
Can cause pretty much any neuro sign

Question 15

How useful is faecal analysis in dx?

Answer 15

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

Question 16

How useful is the angiodetect

Answer 16

Reported numbers are sens 98%, spec 96%, although likely a little less,

Can get false -ves from if tested too early

Question 17

Where do adult worms live?

Answer 17

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

Question 18

What coag test results do you see with DIC?

Answer 18

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)

Question 19

What lab abnormalities may be found?

Answer 19

Eosinophilia in 50% patients
High protein in 75%
May see evidence of DIC
Sometimes (rare) see hypercalcaemia, anaemia

Question 20

How do you treat lungworm?

Answer 20

Imidacloprid/moxidectin or milbemycin are licenced

Can also use fenbendazole

Question 21

How can you treat any respiratory signs?

Answer 21

02

Can try AI doses of steroids although v limited evidence

Question 22

Where does C vulpis reside?

Answer 22

URT

N/B life cycle is very similar to A vasorum

Question 23

What are the clinical signs of c vulpis lungworm?

Answer 23

cough

possible nasal dicharge

Question 24

What is the life cycle of filaroides osleri?

Answer 24

direct life cycle and L1 are thought to be mainly

transmitted from a bitch to its pups in the sputum

Question 25

What are the clinical signs of filaroides osleri?

Answer 25

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’.

Question 26

How do you diagnose filaroides osleri?

Answer 26

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.

Question 27

How do you treat filaroides osleri?

Answer 27

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

Question 28

How does toxocara canis cause signs in pups?

Answer 28

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.

Question 29

Where is Aelurostrongylus abstrusus found?

Answer 29

lung parenchyma and bronchioles, within nodules.

Question 30

What are the clinical signs of Aelurostrongylus abstrusus?

Answer 30

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

Question 31

How do you diagnose Aelurostrongylus abstrusus?

Answer 31

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.

Question 32

How do you treat Aelurostrongylus abstrusus?

Answer 32

Fenbendazole and low dose of prednisolone