w/c 17-Feb-14 Flashcards
Why do we need to take regular blood tests when administering large blood transfusions?
Transfusions contain the anticoagulant, citrate. This citrate can bind to calcium and cause a rapid decrease in [Ca]
Hypoxaemia is defined as
Arterial pO2 < 60mmHg SpO2 < 90%
How does pyrexia lead to Hypoxemia?
Pyrexia increases O2 demand. Any increase in basal metabolic rate will lead to increased o2 demand.
Normal range for Co2 levels?
35-45mmHg
Hypercapnia can occur due to hyperventilation, rebreathing exhaled gas, increase BMR
Hypercapnia can lead to:
Hypercapnia causes tachycardia, hypertension, cardiac arrthymias. INCREASED INTRACRANIAL PRESSURE, respiratory acidosis
How do the pressures vary between spontaneous breathing and IPPV? What are the implications of this?
Spontaneous breathing intrapleural pressure remains negative.
When ventilating the intrapleural pressure remain above zero throughout cycle/
Decreased venous return = decreased cardiac output
What is important to remember when doing IPPV
Don’t just ‘squeeze’ whole bag, work out tidal volume (10-15ml/kg), want end tidal co2 to be 35-45.
want POSITIVE END EXPIRATORY PRESSURE!!!
What are potential causes of bradycardia?
- High vagal tone
- Electrolyte acid/base disturbances ((esp K+ high)
- Hypothermia (less anaesthetic required)
- a2 agonists (cause vasoconstriction then baroreceptor reflex)
- Raised intracranial pressure
Which arrthymia is common following a2 administration?
alpha 2 agonist e.g. medotomidine/ xylazine is arrthymogenic and can cause AV block
How does the type of fluid used to treat hypovolemia vary depending on amount of blood lost?
10-15% loss: Crystalloid
15-25% % Colloid
>25%: Blood (beware citrate anticoagulant binding to calcium) OR if PCV <20%
Blood volume in dogs is calculated by
80-90ml/kg= dog 60-70ml/kg = cat
Examples of inotopes
Dopamine: Acts of DA receptors at low concentration but higher concentration acts of a1 or b1 receptors. Tachycardia in horses, NOT USED
Dobutamine: Acts mainly on b1 receptors. Acts on a1 and b2 receptors but tend to cancel each other out.
Less arrthymogenic than dopamine
Why is hypothermia a problem in anaesthesia?
Hypothermia:
Reduces requirement for anaesthetics
-Alters pharmokinetics of drugs –> prolonged recovery
- shivering increases oxygen demand in recovery
- increases blood loss (increased clotting times)
- increased surgical wound infections (humans)
The cushing reflex is
It can be treated by:
'Impending death' Increased blood pressure Bradycaria Respiratory changes if not ventilated. Treatment: hyperventilate to vasoconstrict vessels, use mannitol/ furosamide
Anaesthetic considerations for rabbits
- Post operative ileus (esp with morphine)
- Anorexia / stress
- More difficult to intubate
- Subclinical resp disease ‘snuffles’ common - Pasteurellosis
Hyponorm is a mixture of
Fentanyl and Fluanisone (is a butyrophenone)
Which reflexes are indicitive of a medium-deep plane of anaesthetic in rabbits?
Tail pinch: Lost at light plane
Toe pinch: Medium-deep
Ear pinch: Medium-deep
Palpebral: Reflex useless
What is important to consider during a rabbits Recovery from anaesthesia?
-Hypothermia common
- Provide appropriate analgesia
- Encourage eating and return to owner ASAP.
Want to avoid post operative ileus
Potential ways to avoid post operative ileus in rabbits
Prokinetics - Ranitidine/ Metaclopromide (antiemetic but prokinetic) -Dopamine antagonist
- Get owner to bring in own food/ drink bowl
- Avoid stress- hospitlise away from other species if possible
Which analgesics are licenced for use in rabbits?
NON ARE LICENCED
Morphine can cause ileus
Buprenorphine most often used (opiods)
NSAIDs (meloxicam well tolerated)
Pre-anaesthetic preperation for rabbits?
No need to starve for long periods.
200grams= 1-3 hours
Remove water one hour before induction
Examine/ flush mouth before induction
IV access in rats, mouse and G.pig?
Rats, mouse, gerbil: Lateral tail vein
G.pig: Medial metatarsal vein
Atropine can be used to prevent excessive salivation
How long should ferrets be starved before induction?
Treat ferrets as cats.
i.e. starve for 6 hours before op. BUT CARE as Insulinomas are relatively common
Ferrets have a thick skin
Hypotension
Pleural diseases as a cause of dyspnoea are common in which species?
Pleural diseases are common cause of dyspnoea in small animals.
Converesely they are UNCOMMON in the HORSE
The characteristic breathing rate/pattern of an animal with pleural effusion is
Rapid shallow short respiration reflecting reduced tidal volume.
I.e. using last bit of tidal volume to breath, orthopnoea
Define Orthopnoea
Shortness of breath when lying flat.
Common presenting sign of animals with pleural effusions
Ausculation of a patient with a pleural effusion =
Volume of pleural FLUID likely to be dullness of auculation of VENTRAL thorax.
Likely to have muffled heart sounds and no lung sounds in VENTRAL portion of thorax.
If pleural effusion is suspected and the animal has concurrent ascities, it is more likely to be…
Protein loosing enteropathy = disseminated disease leading to systemic hypoproteinaemia
If an animal with suspected pleural effusion is systemically ill, what steps do you need to take before undetaking thoracocentesis?
If animal is pyrexia, more likely to be pyothorax therefore when aspirating fluid beware zoonotic bacteria e.g. Nocardiosis = human disease.
Exudate contains sulphur granules
How does haematology help diagnose cause of pleural effusion?
Hypoproteinaemia may suggest protein loosing enterotomy
Neutrophillia with left shift = pyothorax
Hyperglobuinaermia = Feline infectious peritonitris
Evidence of bone marrow involvement in some lymphoid neoplasms
Why would radiographing a patient with a pleural effusion be helpful?
Before and After, check how much fluid has been drained
Also after can check for tumours/ mediastinal masses
A radiograph showing dark space around the lung lobes on radiograph is indicitive of
Pneumothorax (air)
How are pleural effusion diseases treated?
Remove fluid (thoracocentesis) and treat underlying CAUSE e.g. Right sided heart failure, neoplasm, feline infectious peritonitis (POOR PROG), Diaphramatic hernia
How is pyothorax treated in small animals
Hard to drain due to the viscous nature.
Insert indwelling drains and flush with saline.
Systemic antibiotics.
What is a cylothorax
Difficult to manage., Failure of lymph to drain normally via the thoracic duct. Various aetiologys:
- Lymphosarcoma, heart failure, IDIOPATHIC.
How is chylothorax treated?
Treat underlying disease e.g. RSHF, Neoplasm
Medical management involves low fat diet,
Surgical management: Ligation of all branches of thoracic duct, provide alternative route.
If neither work Pleurodesis (v. uncomfortable)
If the animal has a diagnosed pneumothorax but it is not affecting the animals breathing. What is the recommended treatment?
If small in volume and no significant pulmonary abnormalities it will be reabsorbed over a period of days, No further action (MONITOR!)
If large volume, enter needle (3 way tap) DORSALLY,
How can a transudate and exudate be distinguished?
Transudate: Almost water like. Few nucleated cells. Protein 5g/l)
EXUDATE: Proetin content >30g/l
Cell count >50x109
Ddx for modified transudate
Cell count 1.5 x 109l Protein 25-40g/l
Heart failure, neoplasm, diaphramatic rupture
Ddx for exudate
Penetrating injury, Migrating forein body, pleuropneumonia, feline infectious peritonitis
Ddx Chylothorax
Often ideopathic, damage to thoracic duct.
Neoplasm
Heart failure
Equine Pleuropneumonia is most likely…
Mixed bacterial infection that are normal flora of the pharynx due to suppression of pulmonary defense.
- Transport over long distances
- Strenous exercise
- Surgery, anaesthesia
- Foaling
Equine Pleuropneumonia normally has what type of distribution
Cranioventral distribution due to main stream bronchi
Which bacteria are involved withe quine pleuropneumonia
Normal flora of the pharynx
-Ecoli, Klebsiella, Pasteurella, Bordatella, Bacteroides.
How do the acute/chronic signs of equine pleuropneumonia vary
Acute: Pyrexia, lethargy, shallow breathing, stiled gait, pleurodynia
Later: Nostril flare, tachycardia, increased jugular pulse height (fluid), toxic mucous membranes
Chronic: Intermittent fever, weight loss, ventral oedema
Diagnosis of equine pleuropneumonia
History (travelling?Stress?), thoracocentesis, TRANSTRACHEAL ASPIRATE (as its normal pharangeal mucosa, can’t contaiminate)
4 aims of treatment for equine pleuropneumonia
Remove excess pleural fluid - INDWELLING
Antibiotic therapy
Antiinflammatory/ analgesic
Supportive care (oxygen, bronchodilators, fluids, nutrition)
Ideal antimicrobials for treatment of equine pleuropneumonia
Penicillin, Gentamycin, Metronidazole THEN BASE ON CULTURE/SENTITIVITY
Problems with stocking different age groups together (dairy herd)
Older animals may be shedding pathogen that they are immune to.
Could be first exposure for younger animals= clinical disease.
NOT GOOD PRACTICE
How can a simple inhouse test tell you whether the calf has consumed enough collostrum>
-Take blood sample from HEALTHY CALF
- Let it clot, remove serum
-Test serum using refractometer
Want it to be 5.5 or above
When testing serum for adequate collostrum intake, why should ill calfs not be used?
If calf is already ill, artificially high specific gravity due to dehydration.
If adequate colostrum in healthy calf should be >5.5
Enzoonotic Pneumonia primary pathogens
The primary pathogen damages the respiratory tract e.g. Virus or Mycoplasma
Allows for secondary pathogen to invade and cause damage
Which 3 virus cause serious respiratory disease in cows
Bovine Respiratory Syncitial virus, Infectious Bovine Rhinotrachitis, Bovine Coronavirus
(Parainfluenza = mild)
Which secondary bacteria can invade following initial damage (in cows)
Mannhemia haemolytica (A1&A6)
Pasteurella multocida
Arcanobacterium pyogenes
Histopillus somni
You arrive on a farm where 4 calfs have respiratory disease, what steps do you take
SUSPECT PNEUMONIA
- Individual examination of 2/3 calfs
- Take temperatures of ALL IN GROUP
= Treat all with pyrexia (>39.7)
Which two groups of drug are used to treat pneumonia
Antibiotics
NSAIDs (decrease temperature, increase appetitie)
Nuflor (Flurifenicol) should NOT be used in
Breeding males.
Effective against bovine respiratory disease e.g. Mannhemia haemolytica
When trying to identify pathogens causing respiratory disease in calfs, which are the best ones to sample?
Those in VERY EARLY stage of disease e.g. those that are just Pyrexic (above 39)
PME any dead calfs
Paired serology
IBR signs
Pyrexia, Conjuctivitis, Coughing, Trachetisis (asculatae trachea) –> can be severe. Trachitis is obvious on PM
Caused by BHV-1
BHV-1
Most identifiable on nasopharangeal swab.
= Infectious bovine rhinotrachitis (IBR)
Also has a RARE genital form- vulvovaginitis
BHV-1 (IBR) can be latent, where does it reside?
Trigeminal Ganglion (CN V)
Can recrudesce and shed again during periods of stress–>pregnancy, parturition, transport.
Cannot RELIABLY DETECT, Sero-negative may still be latent . Take BULK MILK ANTIBODY TITRE
IBR - type of vaccination and how quickly they work
Live, Dead, Marker (DIVA)
Live vaccines induce rapid immunmity, 40-96 hours
Often only single dose.
Young animals may need 2 doses due to MDA
Pathogen causing Calf Diptheria. Most characteristic sign is…
Fusobacterium necrophorum.
Calf Diptheria = necrotic laryngitis.
Lesions in mouth, tongue and larynx, Produces foal smelling necrotic lesions.
OFTEN HAVE HALATOSIS
Cause of Calf Diptheria
Mucosal injury from teeth, poor hygiene of feeding equipment, poor hygiene of feeding equipment, coarse feeds.
Fusobacterium necrophorum
When is aspiration pneumonia a problem in cows?
Very severe pneumonia caused by inhalation of milk.
Associated with stomach tubing INCORRECTLY
Cause of shipping fever / Presenting signs
Pneumonic Pasteurellosis. Mannhaemia haemolytica, Pasteurella multicida
Normally seen 10-30 days after transport = GOOD HISTORY,
Presenting signs: Sudden onset, depressed appetitite, increased respiratory rate, grunting, found dead.
Cause of Fog Fever
AKA: Acute bovine Pulmonary Oedema and Emphysema.
Non infectious disease.
Asssociated with cattle grazing lush pasture.
Within 2 weeks of moving to Autumn pastures due to TRYPTOPHAN
When you suspect Fog Fever what is the first line of treatment
REMOVE FROM PASTURE! Tryptophan metabolised to 3-Methyl Indole = pneumotoxic.
CARE MOVING OFF PASTURE. STRESS= DEATH.
Systemic NSAIDs, Diuretics, Corticosteriods (NOT IF PREGNANT!= ABORTION)
Bovine Farmers lung is caused by
Hypersensitivity following inhalation of allergens from moulds (poorly made hay)
Housed cattle with poor ventilation,
DON’T FORGET LUNGWORM AS DDx
How would the ausculatation sounds vary between Pneumothorax and Hydrothorax?
Pneumothorax: Same/ enhanced lung soudns
Hydrothorax: Reduced/absent lung sounds
Fluid: more ventral
Air: more dorsal
Most intranasal tumours are
MALIGNANT. Solid carcinoma, adenocarcinoma or chondro,fibro, osteoSARCOMA.
One exception: Benign polypoid rhinitis (very rare but only indistinguishable on histopath)
Primary and Secondary Pathology of Brachycephalic airway obstruction syndrome
Primary pathology: Stenotic nares, Long soft palate
Secondary pathology: Evertion of the lateral larngeal ventricles, Larngeal collapse
What is a common complication of stressed and severely dysnopic brachiocephalic dogs?
Laryngeal and Pharyngeal oedema develops (which worsens the situation)
Tracheal Hypoplasia is very common in which breed of dogs? What is the treatment?
Bulldogs are very suseptible to tracheal hypoplasia (a narrowing of the trachea). There is no treatment for this condition.
Procedure when playing trachetomy tube
Try to be aseptic (not in emergency)
- Ventral midline skin incision in neck, 2-4 cm caudal to larynx
- Seperate stenohyoid/sternothyroid muscles to reveal trachea
- LONG STAY SUTURES (Can stablise trachea/pull to surface)
- TRANSVERSE incision between the fourth and fifth tracheal rings
When and HOW do you remove the tracheotomy tube?
When the dog demonstrates adequate upper airway movement (air flow around tube)
Remove tube and leave to heal by SECOND INTENTION
Clinical features of Laryngeal paralysis
Can be congenital, Acquired, Idiopathic
- History of exercise intolerance
- Dysphonia
- Increased respiratory noise (esp inspiration)
- Cyanosis and collapse
- Often hyperthermic
Treatment of Laryngeal paralysis
If acquired and known (e.g. trauma, neoplasia- mediatinal/thyroid, hypothyroidism) TREAT UNDERLYING
LEFT ARYTENOID LATERALISATION (suture of arytenoid to the thyroid)
Cause and Signalment of Tracheal Collapse
Cause: Poor tracheal cartilage development (low glycosaminoglycans)
Signalment: Small toy breeds e.g. poodles
Goose honk cough.
Can often palpate a dorsoventral flattening of the trachea (can occlude airway with pressure)
First and Second line of treatment for Tracheal Collapse
First line of treatment is MEDICAL: Older dogs more likely to have other more important diseases. Loose weight, steroids may help control oedema.
Second line of treatment: SURGICAL (only if tracheal collapse is primary disease)
How does the surgical treatment for tracheal collapse vary depending on the age of the animal
Prosthetic rings if younger animal
Intraluminal stends for older dogs with co-morbid disease
Subcutaneous empysema which can be generalised over the whole body is very indicitive of which type of lower airway pathology
Subcutaneous emphysema (air under the skin) is very indicitive of tracheal laceration/trauma e.g. dog bite wounds (always aim for neck!) Other clinical features: Pneumomediastinum --> Pneumothorax (respiratory distress)
Most common type of primary lung tumour in the dog?
Most are malignant.
Adenocarcinoma is the most common.
Normally the right middle and right cranial lung lobes are most frequently involved in lung lobe torsion. Which species is the exception where THE LEFT lobe is involved
In pugs it is normally LEFT LOBE TORSION.
Normally narrow deep chested dogs
Clinical features of all torsions: Depressed, inappetent, dyspnoea/cough/ muffled lung sounds.
The torsions are normally associated with pleural effusion causing collapse and then twisting follows
Treatment of lung lobe torsion
Normally right medial/cranial lobes.
DO NOT UNTWIST (releases toxins) just use staples.
Affected lobe looks like liver instead of lung.
Why is it important to differentiate acquired from spontaneous pneumothorax?
Acquired: Thoracocentesis
Spontaneous (no history of trauma): REFER as more likely to need surgery
What are the diaphram attachments?
Dorsally to L3 and L4.
Ventrally to Sternum
Laterally to ribs/ sternum
Treatment of Acquired Diaphramatic Disease
Acute post trauma patient: 24-48 hours stablisation prior to repair of the diaphramatic hernia.
If radiography reveals dilated stomach within thoracic cavity = immediate trans-thoracic gastrocentesis. If decompression cannot be maintained = emergency surgery indicated
In which breed of dog is Oesophagial hiatial hernia (EHH) thought to be hereditary>
Shar-Pei dog.
Laxity of the oesophageal hiatus allows the abdominal oesophagous and cardia of stomach to slide into thoracic cavity.
Clinical signs of EHH>
Oesophageal Hiatial Hernia.
Clinical signs = gastrointestinal reflux, regurgitation and/or vomiting.
Chronic oesophagitis, Aspiration pneumonia
What are the main lungworms is a) horse b) dog c) cat
a) Horse: Dictocaulus arnfieldi
b) Dog: Angiostrongylus vasorum/ Filaroides
c) Aelurostrongylus abstrusus
Equine lungworm Diagnosis
DICTYOCAULUS ARNFIELDI
- Grazing History (DONKEY sharing grazing)
- Faecal examination (McMaster method –> embronated eggs)
- Tracheobronchial washing
- Response to anthelmintic treatment
How do the tests differ for D.arnfieldi depending on time following expulsion?
Faecal examination.
If faeces passed and examined immediately = embryonated eggs (McMaster method)
If faeces passed then left for a bit = test for L1 i.e. Baerman technique
TYPE of lungworm that infects dog
Angiostrongylus vasorum is a TYPICAL Metastrongyloid namatode (indirect life cycle, slugs/snails 2cm).
Predilection site: Pulmonary arteries, RHS heart.
Cardio-respiratory signs/Coagulopathies/ Neurological signs
Mechanism by which Angiostrongyulus vasorum leads to coagulopathy in dog
Subcutaneous haematoma, internal haemorrages, prolonged bleeding from wounds.
MECHANISM: Thrombocytopenia, Decrease clotting factors.
Scleral haemorrage/ retinal haemorrhage
Diagnosis of Angiostrongylus vasorum
Bearman technique for examination of L1 in faeces OR sputum
PPP: 6-10 weeks.
Blood: Idexx ELISA
Easinopohillia/ coagulopathy tests
Treatment of lungworm in the dog
Two licenced:
Moxidectin (advocate) - single dose prevents infection for a month
Milbemycin (milbemax) - weekly for 4 weeks)
OFF LABEL
Fenbendazole (panacur) daily for 1-3 weeks (works by starvation as is a benzimidazole)
Filaroidies lifecycle and transmission
Much less common than A.vasorum
Atypical Metastrongyloid
Direct life cycle. Transmission bitch to puppy during grooming.
Can be asymtomatic –> dry cough.
Diagnosis Filaroides
DIFFICULT as very few and sluggish.
Bearman technique used to recover L1
Endoscopy VIEW TRACHEAL NODULES –> confirm diagnosis.
TREATMENT: Fenbendazole for 7 days
Would you you expect on post mortom in a cat infected with Angiostrongylus abstrusus?
Typical metastrongyloid.
Greenish nodules in lungs (green when unstained)
Dictyocaulus arnfieldi is the most common respiratory parasite of horses. Which others are relatively common?
Parascaris equorum (migrating larvae)
How does the diagnosis of bovine lungworm differ from the diagnosis of equine lungworm?
Dictocaulus viviparvous (cow) = Trichostrongyle. Bearmans test for L1 larvae D. arnfieldi if tested immediately after passing faeces= McMaster for embroynated eggs.
Cause of parasitic bronchitis in cows?
The trichostrongyle Dictyocaulus viviparus.
Lower milk yield in cows.
PPP: 3.5 weeks
Found in trachea and larger bronchi
How can you differentiate Dictyocaulus viviparus from Ostertagia in cows?
Both trichostrongyles.
GIT parasite: Longer, Intertinal CELLS
Lungworm parasite: Short, blunt tail, Intestinal GRANULES
Pathogenesis of D. viviparus
Penetration phase: Larvae migrate to lungs (even after vacc) Prepatent phase (1-3 wks): EASINOPHILLIC EXUDATE in bronchioles. Start clinical signs due to alveolar collapse distal to blockage. Tachypnoea/Coughing
Pathogenesis of Parasitic Pneumonia in cows?
D. viviparvous (granules causes areas of consolidation due to reaspiration of eggs + larvae
= cellular infiltration by polymorphs, macrophages
Why should vaccinationed and unvaccinated cattle not be kept on the same pasture?
Vaccinated cattle still excrete SOME L1 in faeces.
Can cause DISEASE in unvaccinated.
BUT ALSO Unvaccinated create MASSIVE CHALLENGE = disease in VACCINATED cattle as well.
VACCINATION PREVENTS DISEASE NOT INFECTION
On PM examinated which lung lobes are most commonly infected with D.viviparvous?
Diaphramatic lobes have plum coloured areas of consolidation. If placed in formulin will sink due to lack of air space
Two lungworm of sheep and their life cycles.
Dictyocaulus filaria: Lungworm of sheep with direct life cycle
Muellerius: Indirect, mollusic host, adult worms in alveoli. Creates nodular lesions = NOT SIGNIFICANT
How are D. filaria and Muellerius differentiated?
D. filaria: Granules (as all lungworm) BLUNT TAIL
Muellerius: Granules. Blunt tail WITH SPINE
‘Lead shot’ nodules.
