Nasal Discharge & Sinusitis Flashcards
1
Q
Where is bilateral nasal discharge usually localised to?
A
- Usually indicates disease behind the nasal septum
- (Unless bilateral disease of nasal cavity which is pretty unusual)
2
Q
Where is unilateral nasal discharge usually localised to?
A
Usually originate rostral to the caudal end of the nasal septum
3
Q
Causes of bilateral nasal discharge?
A
- Pharyngeal disease
- Pharyngitis
- URT viral and bacteria diseases
- Guttural pouch mycosis, tympany, empyema
- Laryngeal disease
- Arytenoid chondritis
- Lung disease
- Inflammatory conditions (RAO/Asthma)
- Infectious conditions (pneumonia)
- Neoplasia
- Haemorrhage
4
Q
Causes of unilateral nasal discharge?
A
- Nasal foreign body
- Nasal tumour, polyp, cyst
- Fungal rhinitis
- Nasal trauma
- Unilateral sinusitis
- GP empyema
- GP tympany
5
Q
What does purulent nasal discharge indicate?
A
- Indicative of infection / severe inflammation
- Containing neutrophils
6
Q
Purulent nasal discharge may be associated with a foul smell, if so what could this indicate?
A
- Often due to anaerobic infection
- Or could be due to necrotizing tissue disease, such as:
- Fungal disease
- Tumour
- Oro-sinus fistulae and other dental diseases
- Turbinate necrosis
- Necrotizing pneumonia
- Foreign bodies
7
Q
What likely organisms may be associated with guttural pouch empyema?
A
- Streptococcus equi subsp equi (need to be most concerned about this one)
- ‘Strangles’
- Streptococcus equi subsp zooepidemicus
8
Q
How would you confirm a diagnosis of Guttural pouch empyema that may be due to Streptococcus equi subsp equi?
A
- Nasopharyngeal swab (for bacterial culture)
- Guttural pouch wash
- Bacterial culture
- PCR diagnosis
- Serology (specific markers of strangles bacteria)
9
Q
How useful is serology in terms of suspected S.equi infection?
A
- Good at determining recent (but not necessarily current) S equi infection,
- Determining the need for booster vaccination
- Does not distinguish between vaccine and infection response.
- If the animal has recently been exposed to disease this can be useful
10
Q
If serology is low for an animal we have assumed is infected with S.equi, why could this be?
A
- Early infection (<14 days)
- No S.equi equi involvement
- Not exposed to S. equi equi in previous years
- Immunocompromised (unlikely)
- Lab error (unlikely)
11
Q
In what 4 ways can serology for S.equi be interpreted?
A
- Negative
- Weak Positive (1 : 200–1 : 400)
- Moderate Positive (1 : 800–1 : 1,600)
- High Positive (1 : 3,200–1 : 6,400)
12
Q
What could a negative serology result for S.equi mean?
A
- No previous exposure to S equi or
- Recent vaccine or exposure (<7 days)
13
Q
What could a weak positive serology result for S.equi mean?
A
- Could be almost anything
- May represent very recent or residual antibody from exposure or vaccine from a long time ago
- Repeat serology in 7 to 14 days to confirm recent exposure. (if increased in this time then active disease)
14
Q
What could a moderate positive serology result for S.equi mean?
A
- 2 to 3 weeks after exposure
- The animal is mounting an immune response
- Infection occurred 6 months to 2 years previously
- Could indicate a waning response if there was exposure a while ago and the antibodies are on their way down
15
Q
What could a high positive serology result for S.equi mean?
A
- 4 to 12 weeks after infection
- 1 – 4 weeks post vaccination
- If not then positive for Strep.equi equi
16
Q
What would you expect to see with bacteriology for S.equi?
A
- Gram positive cocci
- Growing in chains
- Demonstrating beta-haemolysis
- With mucoid colonies (look mucosy)
- Confirm by carbohydrate assay
- Does NOT ferment to sorbitol and lactose
17
Q
Is strangles gram positive or negative?
A
Gram positive
18
Q
Which groups of horses would be more likely to contract strangles?
A
- Highly infectious particularly weanlings and yearlings
- Rarely affects horses >5
19
Q
Why is important for owners to monitor the temperature of ALL horses on a yard regularly (at least once daily) when there has been a case of strangles?
A
- 24 hour window of opportunity to isolate new cases on the premises.
- Early detection of pyrexia and prompt isolation of new cases will help control spreading of the disease on the premises
- Horses develop pyrexia 24-48 hours before becoming infectious to other horses.
20
Q
How does strangles persist in the environment following an outbreak?
A
- In acutely infected horse nasal shedding for 3-6 weeks after the disease, even after the resolution of clinical signs
- Others become carriers (longer term shedding)
- Fomites and contaminated environmental sources
- In ideal conditions may survive up to 9 weeks
21
Q
Clinical signs of strangles?
A
- Non-specific signs initially: fever, depression, inappetence, +/- cough, mucoid to purulent nasal discharge
- Specific signs: abscessation of mandibular, parotid or retropharyngeal lymph nodes (eventually will rupture), dyspnea and dysphagia if abscesses compress larynx or interferes with cranial nerve supply to pharynx
22
Q
Pathogenesis of strangles?
A
- Bacteria attaches to nasopharyngeal epithelial cells > mucosa > lymphatics > lymph nodes
- Multiplies extracellularly
- Resistance to phagocytosis mediated by HA capsule (very thick capsule and surface proteins) and antiphagocytic SeM, Mac proteins
- Abscess formation and rupture/drainage then recovery and (hopefully) development of immunity
23
Q
Is immunity to strangles lifelong?
A
- Natural infection - 76% do not tend to develop the disease again for at least four years
- After this point immunity will wane and animals may develop the disease again
24
Q
Are vaccines available for strangles in the UK?
A
- Vaccines (submucosal) in the UK
- Not always available, important to check if there is current availability of the vaccine
25
How would you treat horses with early clinical signs of strangles?
Penicillin
26
How would you treat strangles horses at the stage of having lymph node abscesses?
* Poulticing and drainage of abscesses
* Antimicrobials not indicated
* ‘*May prolong resolution of the abscess*’
* Will just suppress the bacterium within the LNs and will not allow natural drainage to occur
27
Complications of strangles?
* Anaemia (common)
* IMHA or anaemia of chronic inflammation
* IMHA occurs quite commonly
* Guttural pouch empyema which can progress to chondroids
* Neurological abnormalities (dysphagia, laryngeal hemiplegia)
* Abscesses distant site (Bastard Strangles - rare) E.g. lungs, abdomen, distal skeletal muscle
* Purpura Heamorrhagica (rare but serious) - Immune mediated vasculitis.
28
How would you diagnose and treat abdominal abscesses (as a complication of strangles)?
* Diagnosis: U/S or rectal
* Treatment: long term antibiotics (usually penicillin or trimethoprim sulfa/rifampin) for up to 6 weeks)
29
How would you treat guttural pouch empyema or Chondroids (as a complication of strangles)?
* Want to get rid of chondroids
* Surgery via guttural pouch is not ideal, so instead flushing things out of the pouch is preferred
* Drainage via the pharyngeal openings
* Surgical drainage
* Antibiotics
30
What is purpura hemorrhagica? How does it present?
* generalized vasculitis caused by Type III hypersensitivity reaction
* Thrombosis of small arteries causes massive plaques of oedema etc.
* Skin and muscle necrosis may result
* Ventral oedema, body swelling and petechial hemorrhages on mucus membranes
31
What is the other main differential for strangles?
***Streptococcus equi* subsp *zooepidemicus***
* Most common respiratory opportunistic pathogen
* Much lower infectivity (commensal)
* No need to quarantine animals
* Lesser economical/social impact
32
Diagnosis of purpura haemorrhagica?
Clinical signs, skin biopsy
33
Treatment of purpura haemorrhagica?
* Dexamethasone: 0.05 - 0.2 mg/kg iv
* Prednisolone: 0.5 - 1 mg/kg po
* Analgesics – NSAIDS (if active disease is present)
* IVF
* Palliative measures e.g. hydrotherapy, massage
34
Prognosis of purpura haemorrhagica?
Guarded
35
What should you do in an outbreak of strangles?
* Isolate premises
* Isolate horses which have shown signs for at least four weeks after the signs resolve
* Prevent movement of staff and equipment between cases
* Phenolics are most effective disinfectant for equipment and areas contaminated with organic matter
* Iodophores and chlorhexidine for staff
36
What measures should be used to control strangles?
* Quarantine and culture of incoming horses
* Confirm resolution of disease
* Penicillin - will prevent the disease during initial period
37
How can you confirm resolution of strangles disease?
3 negative nasopharyngeal swabs/GP lavages (to sample fluid from guttural pouch) over 3 weeks tested by culture and PCR
38
What is Guttural Pouch Tympany?
* Gas accumulation within GP
* Abnormal eustachian tube ostea prevents drainage and acts as one way valve
* Non-painful swelling
* MAY AFFECT AIRWAY
39
How is gutteral pouch tympany treated?
* Antibiotics, NSAIDs
* Surgery – drainage into pharynx or opposite pouch (by laser) to fenestrate the guttural pouch
* In dwelling catheter
* Anything to remove the air from the GP
40
Clinical signs of alar fold abnormalities?
* Airflow obstruction
* Exercise intolerance
* Abnormal respiratory noises during fast exercise
41
Diagnosis and treatment of alar fold abnormalities?
* Diagnosis: direct visual examination - excessively prominent alar folds/temporarily suturing the false nostril open
* Treatment: resection of the alar folds
