Respiratory Path Anatomy Flashcards
Congenital anomalies of the nasal cavity and sinuses
Cystic nasal conchae
Cysts of maxillary sinus
Nasal septum deviations
Cleft upper lip (cheiloschisis)
Cleft palate (palatoschisis)
Describe a condition of the nasal cavity and sinuses that is a result of metabolic disturbance
Amyloidosis - in equines
Primary or secondary to chronic purulent infection / tumours
Nodular or diffuse
May cause obstruction of nasal passages
Gross appearance = smooth, waxy, opaque
Histology = deposited extracellularly near vessels, in basement membranes and connective tissue.
Describe epistaxis
Bleeding from the nose, origin of bleed is a site other than the nasal mucosa.
Sudden large amounts of blood = pulmonary haemorrhage fatal in eq/bovine
Other causes: local trauma, neoplasm, aneurysm. Coagulopathies such as vitamin k deficiency, or warfarin poisoning.
Inflammation of the nasal passages is called …… and we know these types ………..
Rhinitis
Types:
1. Catarrhal - outpouring of mucus
2. Purulent / suppurative- severe inflammation with large number of NEU
3. Fibrinous - presence of FIBRIN outside plasma = vascular damage (fibrinogen becomes fibrin in tissue)
4. Pseudomembranous / pseudodiphteritic = mucus lays on membrane that is not fully ulcerated
5. Haemorrhagic - blood present
6. Ulcerative - ulcers present
7. Granulomatous - chronic type with mononuclear cells predominate and nodules/masses form (actinobacillus/ TB)
What type of inflammation is common in mycobacterial infections? Describe what it may look like
Granulomatous chronic inflammation is common in infections of actinobacillus or TB.
Chronic specific Inflamed tissues are infiltrated by mononuclear cells such as lymphocytes and fibrous tissues replace original tissue cell structure. Fibrous tissue forms nodules or masses around bacteria. At the periphery fribroblasts and fibrocytes can be found.
What is IBR
Infectious bovine rhinotracheitis / red nose
Caused by: BHV 1 bovine herpes virus
Clinical signs: abortion, generalised calf disease, enteritis in calves, conjunctivitis, infertility, encephalitis, skin lesions of udder, inflammation and necrosis of the ovaries.
Gross findings: focal necrotising changes
Days 1-3 acidophillic intranuclear inclusion bodies expected in epithelial cells (rarely seen at necropsy).
Describe atrophic rhinitis
Inflammatory disease of pigs caused by PASTEURELLA MULTOCIDA & BORDATELLA BRONCHOSEPTICA / HAMEOPHILUS PARASUIS
Predisposing factors: genetic susceptibility, bad environment , viral infections (cytomegalovirus).
Acute stage: sneezing, coughing, serous muco-purulent nasal discharge. Dried dirt, lacrimal secretions in medial can this due to blocked nasolacrimal duct.
- atrophic lesions of turbinates caused by toxins that have an adverse effect on OSTEOBLASTS in some areas.
- secondary irregular hypertrophy of some areas.
Asymmetric atrophy and growth of nasal area and sinuses causes DEVIATION and median septum distortion.
DDX - cut transverse cross section of snout between premolars 1 & 2
Histology: hypoplasia of cancellous bone, exudate and epithelial destruction. Hyperactivity and distension of submucosal glands. Chronic mononuclear cell infiltration of lamina propria.
Characterise strangles
Equines stressed in transit or overcrowding, other situations.
Multiple bouts in lifetime possible as immunity is short lived.
Cause: STREOPTOCOCCUS EQUINES
Clinical signs: fever, coughing, conjunctivitis, nasal discharge that is bilateral starts as serous then becomes catarrhal followed by purulent.
LN swelling, rupture and alopecia: submandibular and retro pharyngeal.
Gross picture: nasal exudate, ulceration and embolism of bacteria to other organs liver, kidney, joints, brain LNs (rarely fatal).
Histology: abcessation
Characterise Glanders as an inflammatory disease of the nasal passages and sinuses
Serious notifiable diseas caused by PSEUDOMONAS MALLEI
cutaneous form - FARCY- purulent superficial lymphangitis, ulcerative nodules on ventral abdomen and lower limbs)
Respiratory form manifests as catarrhal to purulent exudate in nasal passages, nodules that are 1cm in diameter on nasal submucosa, ulcers resulting in STELLATE SCARS.
Lungs contain pyogranulomatous lesions that may coalesce into a diffuse pneumonic process.
Histology: nodules in upper and lower respiratory tract are pyogranulomas with NEU and necrosis at the centre. Surrounding is epithelioid macrophages, giant cells, lymphocytes and fibrous tissue.
Describe some inflammatory diseases of the respiratory tract in canines
- ACUTE RHINITIS
Cause: distemper virus, adenovirus 1 & 2, k9 parainfluenza virus, reovirus, herpes virus.
- BACTERIAL RHINITIS
Uncommon usually secondary to viral infection.
Causes: streptococci, staphylococci, E.coli, Bordatella bronchoseptica, mycoplasma’s.
What is MYIASIS? Describe the inflammation of respiratory tract in sheep infected with OESTRUS OVIS.
Fly strike - infestation of tissues by fly larvae.
Oestrus Ovis can be found in nasal cavity of sheep, goats rarely humans.
Larvae are deposited at the nares and undergo TWO MOULTS. Most drop to the ground but some may remain trapped in turbinates/sinuses where they grow rapidly and become stuck.
Physical irritation = catarrhal to mucopurulent rhinitis, erosion of the mucosa, hypertrophy of sinusoidal mucosa and occasionally meningitis caused by penetration of larvae via ethmoidal region or bacterial infection through olfactory tracts.
Species commonly affected by nasal tumours
Dogs - dolichocephalic breeds such as greyhound and GSD
Cats nasal vestibule
Horses maxillary sinus
Types of nasal tumours
Sarcomas - fibrosarcoma, chondrosarcoma, osteosarcoma
Most common are Epithelial tumours - squamous cell carcinoma, adenoma, papilloma, adenocarcinoma
Characterise nasal polyps
Non neoplastic masses that resemble tumours
They develop following chronic inflammation in equines, cats and sheep.
Macroscopically - firm nodules or masses varying in size, may be ulcerated, haemorrhagic or infected secondarily.
Histology - similar to fibromas but have GOOD VASCULARISATION an inflamed core and covered by epithelium.
Causes of circulatory disorders in pharynx, larynx and trachea ? Describe what it may look like
Haemorrhages occur as petechial bruising often seen in the larynx and trachea of cattle and pigs at slaughter.
The speckling seen is caused by small extravasation in submucosal lymph follicles. If cattle die with severe dyspnoea these haemorrhages spread in a linear form.
Characterise tracheitis
Inflammation of the trachea that often arises, due to its location, in the process of inflammatory diseases of the upper or lower respiratory tract.
It often accompanies bronchitis, occasionally pneumonias.
Characterise laryngitis
Laryngitis is the inflammation of the larynx.
Laryngitis may also arise as a result of upper and lower respiratory inflammatory diseases, however it may also occur on its own.
Laryngitis may occur due to:
- oral necrobacillosis caused by FUSOBACTERIUM NECROPHORUM in calves and swine
- laryngeal ulcers or scarred sites are found in slaughtered feedlot cattle, caused by repeated trauma of laryngeal closure during disease.
Describe calf diphtheria / necrotic laryngitis
Common disease of feedlot cattle
Predisposition: intercurrent diseases, nutritional deficiencies, unsanitary housing facilities.
Cause: fusobacterium necrophorum
Infection occurs alongside orolaryngeal necrobacillosis. Bacteria produce various exotoxins and endotoxins which they secrete following entry to the organism following viral infection or a traumatic injury.
Clinical signs: lesions of tongue, gums, cheeks, palate and pharynx.
Macroscopic picture:
Early - lesions consist of yellow-grey necrotic areas, surrounded by a zone of hyperaemia.
Later - deep ulceration, healing by granulation
Histology: lesions which may extend deep into the submucosa have large foci of necrosis bordered by hyperaemia which is surrounded by a band of leukocytes and then granulation tissue/ fibrosis.
describe KENNEL COUGH / canine infectious tracheobronchitis
A contagious respiratory disease of dogs - the term is non specific and describes any disease that has paroxysmal coughing and canine distemper which affects lower respiratory tract.
Cause: a complex of bordatella bronchiseptica, and several viruses
Macroscopic picture: lesions may be completely absent or catarrhal/mucopurulent tracheobronchitis, with enlargement of tonsils and regional LNs.
Histology: exudate rich in NEU, necrosis of the epithelium.
What is the histological picture of vitamin A deficiency and iodide toxicosis
Squamous metaplasia of the tracheal epithelium
What is the most common tumour found in the larynx and pharynx of canines
Squamous cell carcinoma
Congenital anomalies of the lungs
Accessory lungs - located in thorax, abdomen or subcutaneous tissues on the trunk.
Bronchiol hyperplasia and dilation - occur as abnormal lung components (also called congenital cystic disease, congenital adenomatoid malformation)
Agenesis
Abnormal lobulation
Pulmonary duplication
Congenital brinchoectasis
Characterise atelectasis
Atelectasis is the partial or complete collapse of lung/ or its failure to extend - the tissue is airless.
What is foetal atelectasis
When a foetus is still born and fails to make a respiratory effort, the pulmonary tissue is not expanded and remains airless.
What is neonatal atelectasis
A congenital cause of pulmonary failure to expand - animal was able to breath but not to expand enough parenchyma to meet its needs. Atelectasis is patchy in distribution, and is caused by airway obstructions of mucus or birth fluids, or anoxic damage to the respiratory centres in the brain during dystocia.
- neonatal distress syndrome
- hyaline membrane disease
Describe the ways in which acquired atelectasis may occur
- COMPRESSIVE - presence of fluid or a mass, transferred pressure compresses parenchyma stopping it from inflating. Pneumothorax, hydrothorax, chylothorax, haemothorax, empyema, tumours.
- OBSTRUCTIVE - airway is blocked by exudates, aspirated foreign materials, parasites or tumours.
- CONGESTIVE / SHOCK LUNG - severe infection, trauma, blood loss.
- HYPOSTATIC - when large animals are kept recumbent for a long time ie. During surgery, downer cows.
What is the histological picture of atelectasis
Atelectasis of any type appears as DARK and COLLAPSED parenchyma. It may be flabby or firm, if there is oedema or other processes ie. Shock lung.
Histology: alveoli are collapsed completely, or slit like if partial atelectasis.
Bronchioles have a cubic epithelium
What is emphysema
Emphysema is the abnormal, permanent enlargement of air spaces within the parenchyma accompanied by destruction of alveolar walls due to over distension.
Alveolar emphysema vs interstitial
Alveolar: over distension of alveoli and rupture of walls
Interstitial: lack of collateral ventilation (air into lungs but not out) forces alveolar rupture and migration of air into the interstitial tissues. (Cattle mainly)
Which diseases does emphysema occur in
COPD chronic obstructive pulmonary disease in horses
Bovine atypical interstitial pneumonia
Describe the histopathological picture of emphysema
Macroscopically: emphysematous lungs are pale, enlarged sometimes with rib imprints.
Alveolar form - small air bubbles
Interstitial form - bubbles of various sizes in connective tissues
Histology: large accumulations of air called BULLAE or BULLOUS EMPHYSEMA.
All three types alveolar, bullous and interstitial can coexist
Describe metabolic disturbances that may affect the lungs
Amyloidosis - can occur in lung tissues and calcify
Melanosis maculosa - black pigmentation in a lobular fashion occurs in ruminants
