Herp Pulmonology Flashcards
What are the four modes of amphibian respiration?
Are there differences in these respiratory modalities across taxa?
- Modes of respiration
- Pulmonary
- Anurans have bronchial tubes (not bronchi)
- Thin sac-like paired lungs
- Anurans have more compartments than Caudatans & Caecilians
- Left lung shorter in caecilians (some species don’t have one)
- Branchial
- Embryonic respiration – poorly developed gills (some anurans don’t develop them till after hatching)
- Primary respiration for tadpoles
- Neotenic species – Siren, Necturus, Ambystoma, Proteus, Typhlomolge
- Buccopharyngeal – minor
- Buccopharyngeal force-pump for pulmonary & BP breathing
- Cutaneous
- Increased skin folds or hair like structures (Lake Titicaca Frog)
- Primary mode through hibernation
- Pulmonary
Discuss infectious and noninfectious causes of amphibian respiratory distress.
List five parasitic, two fungal, two bacterial, one viral, and three noninfectious causes of repiratory disease.
Parasitic
- Rhabdias – direct life cycle, secondary bacterial infections
- Trematodes – Haematoloechus – lungs and oropharynx of anurans – hyperplastic nodules
- Others – Clinostomum, Diplostomum, Manodistomum
- Ciliated Protozoa
- Trichodonella - gills
- Piscinoodinum – gills
- Flies
- Bufolucilia larvae migrate through nasal passages of adult amphibians
Fungal
- Saprolegnia – poor husbandry, cotton-like appearance
Noninfectious
- Poor water quality
- Hyperplasia of gill epithelium
- Axolotyl – metamorphosis when exposed to thyroxin supplementation
- Rotenone – pesticide casues respiratory enzyme inhibition in frog larvae
What species is this? What is the function of this structure?
Gharial - Nasal excrescence
Vocal resonator
Discuss the laryngeal anatomy of crocodilians and potential implications for intubation.
- Velum palati (dorsal) & gular fold (epiglotic flap, ventral)– crocodilian anatomy to prevent aspiration when oral cavity is filled with water
What is a unique features of crocodilian nares?
Nares – erectile tissue to prevent water getting in
What is unique about the osmoregulation of marine iguanas and sea turtles?
They have salt glands in their nasal cavities.
Identify the three reptilian lung patterns and give examples of each.
- Lung Types
- Unicameral – snakes & some lizards (geckos)
- Paucicameral – Iguanidae, chamaelonidae, Agamidae
- Multicameral – chelonians, varanidae, helodermatidae, crocodilians
What are the functional units of respiration in the reptilian lung?
How do they differ from the mammalian lung?
- Gas exchange parenchyma
- Trabecular – branching muscular structures
- Ediculi – wider than deep
- Faveoli – deeper than wide
- Less gas exchange surface area
What is unique about the tuatara respiratory system?
Single chambered lung, no bronchi
Discuss the chelonian respiratory anatomy.
- Chelonians
- Complete tracheal rings, short trachea
- Attached to ventral carapace by pulmonary ligament
- Cryptodira – retract head and neck straight back
- Short trachea to two main stem bronchi – helps them breathe when head is retracted
- Pleurodira – side necked turtle
- Longer trachea with more caudal bifurcation, longer bronchi as well
- When limbs & neck retracted – lung volume decreased by 1/5
- Multichambered lungs
- Testudo tortoises have simplest lungs (4 chambers)
- Sea turtles have most complex lungs (10-11 chambers)
- Edicular parenchyma
- Post-pulmonary septum aka pleuropeitoneal membrane aka pseudodiaphragm (not in sea turtles)
Discuss ophidian respiratory anatomy.
What species have tracheal lungs?
How many lungs do they have?
- Glottis is cranial and can be moved even more cranial when swallowing prey
- Incomplete tracheal rings
- Tracheal lung – gas exchange when swallowing prey
- Common in Elapids, Vipers, Hydrophiids, and Colubrids
- Cardiac lung – reduced in size (near heart)
- Left lung absent or reduced
- Present in xenopeltids, Loxocemids, Phythons, & Boas
- Colubrids have a vestigial left lung
- Vascular & sacular portions (unicameral lung)
Which reptiles have complete tracheal collagenous rings?
Crocodilians, Chelonians
Discuss saurian respiratory anatomy, including gross and microscopic differences across taxa.
- Incomplete tracheal rings
- Equal lung sizes (not in Amphisbanians & anguimorphs)
- Single chambered (Unicameral)
- Amphisbaenia, Gymnophthalmidae, Teids, Lacertids, Xanthusiids, Scincidae, and Anguidae
- Transitional (Paucicameral)
- Iguanids, Gekkonids, Xenosaurids, Lanthanotus, Chamaeleonids, Agamids
- Multicameral – varanids and helodermatids
- Faveolar – skinks, iguanids, agamids
- Edicular – varanids, chamaelonids, gekkonids (distal portion of iguanid & agamid lungs)
- Skinks also have caudal air sac portion of lungs
- Monitors possess a complete post-pulmonary septum as well (Helodermatids have an incomplete one)
Discuss crocodilian respiratory anatomy.
- Crocodilians
- Palatal valve – dorsal (velum palati), ventral (gular fold)
- Complete tracheal rings
- Tubular multi-chambered lungs, complete mediastinum
- Pseudodiaphgram – posthepatic & postpulmonary membranes
- PH membrane is attached to m. diaphragmaticus connected to the pubis
Discuss reptilian respiratory physiology.
- Physiology
- Respiratory cycles
- Variable periods of apnea
- Squamates – intercostal muscles
- Chelonians – movement of inguinal, axial, and shoulder muscles
- Crocodilians – expiration & inspiration active (expiration passive underwater like in turtles)
- Stimulus
- Decreased PaO2 – stimulus to breathe
- Increased PaCO2 – stimulus for deeper breaths (increased tidal volume)
- Ventilation perfusion mismatch – can occur when large animals on their backs
- Lung oxygen reserves are most important for diving species
- Respiratory cycles
List differentials for reptile tracheitis.
Tracheitis
- Inflammation, granulomas, chondromas, lymphomas, exudates
- Etiologies
- Mycoplasma, Salmonella, Nidovirus, Iridovirus, tracheal chondromas
What bacteria are commonly isolated in cases of bacterial pneumonia?
- Etiologies: Mycoplasma, Aeromonas, Alicaligenes, Chlamydia, Citrobacter, Corynebacterium, Enterobacter, Escherichia coli, Klebsiella, Morganella, Moraxella, Pasteurella, Proteus, Pseudomonas, Acinetobacter, Brevibacterium, Achromobacter, Bacillus, Stenotrophomonas, Empedobacter, Salmonella, and Mycobacterium
- Sick snakes tend to have more gram negative bacilli (healthy snakes have more Providencia and Staphylococcus in their lungs)
- Mycoplasma agassizi & testudineum
- Clarithromycin and oxytetracycline preferred over fluoroquinolones
Differentials and treatments for reptilian fungal pneumonia.
Fungal Pneumonia
- Etiologies: Aspergillus, Candida, Fusarium, Mucor, Geotrichum, Penicillium, Cladosporium, Rhizopus, Chrysosporium, Paecilomyces, and Beauveria
- Large encapsulated lesions require surgical removal
- Small lesions may still need it if well encapsulated
List and discuss differentials for reptilian viral pneumonia.
Viral Pneumonia
- Herpes
- TeHV1 – Russian tortoises
- TeHV2 – desert tortoises
- TeHV3 – Testudo & Russian Tortoises
- Intranuclear inclusion bodies
- LET disease
- Fibropapillomatosis (ChHV5)
- Ranavirus
- URT disease in chelonians – nasal and ocular discharge, conjunctivitis, palpebral edema, caseous plaques in oral cavity, and pneumonia
- Paramyxovirus
- Hyperplasia of type II pneumocytes
- Ferlavirus
- Most commonly crotalids
- Also seen in colubrids, elapids, viperids, boids, & pythons
- Transmission by contact, secretions, fomites, mites
- Sunshine virus
- Neurorespiratory disease in Australian pythons
- Inclusion body disease
- Boas more likely to have respiratory signs
- Adenovirus can casue pneumonia
- Nidovirus – pneumonia in ball pythons
List and discuss differentials for parasitic pneumonia in reptiles.
Parasitic Pneumonia
- Rhabdius – lungs of snakes and lizards
- Strongyloides – migrating larvae
- Pentastomids – parasitic crustaceans (tongue worms) – visceral migrations
- Coccidia in Crocodile lungs
- TINC in tortoise lungs
- Encephalitozoon pogona in bearded dragon lungs
Discuss diagnostic approaches to reptilian pulmonic disease.
Diagnostics
- Tracheal wash (5 mL /kg sterile saline)
- Percutaneous lung lavage in chelonians
- Transcutaneous endoscopy
- Right lateral approach – small incision at level of semisaccular lung
- Place stay suture in lung prior to taking samples
- Lung closed with simple interrupted or ligations prior to sampling
- Osteotomy sites can be used to place a catheter for drug administration
- Biopsy
What is the most likely etiology of the lesion in this Python regius?
Discuss treatment options and approaches.
Tracheal chondroma
Tracheal Resection
- Endoscopic evaluation & biopsy for treatment options
- Saccular lung canula in snakes with chondromas until surgery can happen (55-70% SVL)
- Cuffed endotracheal tube, sutured in place, filter at end
- Removal recommended in 48 hours
- Careful dissection to avoid all the important things (jugular, carotid, esophagus - thymus and great vessels if more caudal) and find just the trachea - trachea usually to the right of midline
- Stay sutures, anastomosis with 4-0 to 5-0 PDS tied extraluminally, consider additional tension relieving sutures on each side
- Tracheoscopy in 6-8 weeks to confirm healing
Discuss your radiographic findings
Discuss these radiographic findings
Pneumonia - pronounced consolodation of mid-to-caudal right lung
What is this parasite?
What species are you likely to find this in?
Pentastomid
Aquatic reptiles - crocodilians, turtles, snakes
Describe your approach to transcutaneous pulmonoscopy in a snake.
Right lateral approach with snake in left lateral recumbency (in boids with both lungs, either approach is fine)
Incision at the level of the semisaccular lung to avoid hemorrahge
Stay sutures to bring lung closer to body wall, perforate the lung for scope, close with simple interrupted suture
Describe pulmonoscopy in chelonians using both carapacial and prefemoral approaches.
Carapacial
3.5 or 5 mm osteotomy with orthopedic drill over site, entry into lung with straight hemostats then pass endoscope, close lung if possible (not required with this approach), cover osteotomy with epoxy resin (can place a catheter for intrapulmonic drug administration).
Prefemoral
Prefemoral - lateral recumbency, incision at craniodorsal margin, stay sutures to bring lung clsoer to incision, stab incision through avascular window to advance endoscope, close the lung
Describe the surgical procedures performed on the reptilian lower respiratory tract.
Tracheal Resection
- What are some indications for tracheal resection?
- Describe the placement of air sac canula in snakes for emergency management until the resection can be completed
Lung Biopsy
- Describe the approach to lung biopsy in a squamate.
- How does it differ for a chelonian
Mass Removal
- What approach is needed to remove a mass for squamates or chelonians?
- How is the diseased area removed?
MARMS – 102. Lower Respiratory Tract Sx
- Tracheal resection:
- Tracheal chondroma, lymphoma in boid snakes.
- Mycotic granulomas in a tortoise.
- Rads/CT to determine nature and extent of pathology.
- Endoscopy/bx of tracheal lesion.
- Snakes – can place temporary saccular lung cannula until surgery.
- 55-70% SVL to avoid vascular lung.
- Removal within 48h of placement is recommended.
- Trachea usually to right of midline in snakes.
- Left lateral recumbency, right approach recommended for RNA.
- Avoid – right carotid artery, jugular vein, smaller vascular supplies to trachea.
- Placement of esophageal catheter helpful to aid in ID and preservation of left jugular, left carotid, esophagus.
- Stay sutures to elevate trachea.
- Caudal trachea – avoid thymus and great vessels.
- Full-thickness simple interrupted sutures tied extraluminally.
- Lung biopsy:
- Pre/post contrast CY preferred, or rads.
- Dissection between ribs, access craniodorsal coelom.
- Endoscopy is valuable for ID and grasping lung, exteriorizing through intercostal space.
- Otherwise max inspiration will often facilitate grasping the inflated lung.
- Transfixing circumferential suture to isolate small section of lung before sharp resection.
- Observe for leakage during maximal ventilation.
- Chelonians – Similar procedure can be performed through prefemoral fossa, restricted to caudolateral aspect of lung.
- Alternative carapacial approach also described.
- Not necessary to close pleuroperitoneum.
- Small osteotomy closed with epoxy or acrylic.
- Intrapulmonary catheter can be placed for therapy.
- Alternative carapacial approach also described.
- Mass/abscess/granuloma removal:
- May require ventrolateral coeliotomy for greater exposure than intercostal approach.
- Chelonians – larger dorsal carapacial flap can be used.
- Transfixing circumferential suture preferred to isolate the diseased area because of difficulty assoc with suturing lung tissue.
- Removal of pulmonary tissue usually well tolerated but may result in long-term asymmetrical swimming in aquatic chelonians.
