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| + | *Congenital abnormalities of lungs are very rare, but most common in cattle |
| + | *Most congenital abnormalities are incompatible with life |
| + | |
| + | |
| + | ===Accessory lungs=== |
| + | |
| + | *Most common developmental disorder, especially in cattle |
| + | *Incompletely differentiated pulmonary tissue present anywhere in the trunk |
| + | *Grossly: |
| + | **Lobulated oedematous masses |
| + | **May be connected to uper alimentary tract |
| + | *Histologically: |
| + | **Dialated structures resembling bronchioles |
| + | **Alveoli and ducts developed to varying degree |
| + | *May cause birthing difficulties |
| + | |
| + | |
| + | ===Ciliary dyskinesia=== |
| + | |
| + | *See [[Nasal Cavity Developmental - Pathology#Ciliary dyskinesia|Nasal cavity]] |
| + | |
| + | |
| + | ===Congenital melanosis=== |
| + | |
| + | *Affects pigs and ruminants |
| + | *Is not clinically significant, often found at slaughter house |
| + | *Black spots in various organs, including lungs |
| + | *See [[General Pathology - Pigmentation and Calcification#Melanin|melanosis in general pathology]] |
| + | |
| + | |
| + | ===Congenital atelectasis=== |
| + | |
| + | *Incomplete expansion of the lung at birth (congenital) or collapse of previously air-filled lung ([[Lungs Ventilation - Pathology#Atelectasis (Collapse)|acquired]]) |
| + | *Failure of lung tissue to expand at birth |
| + | *Ranges from total in stillborn animals to patchy areas in the case of weak neonates, showing more in the dependant lobes in recumbency |
| + | *'''The neonatal respiratory syndrome''' |
| + | **Best documented in foals but reported in other species |
| + | **Also features extensive atelectasis |
| + | **These animals are called 'barkers' due to the noise made during forced expiration |
| + | *Gross pathology: |
| + | **Red fleshy appearance to the affected part, depressed below the surface if there are adjacent normal aerated areas |
| + | **Cut surface oozes blood, perhaps some froth in 'barkers' |
| + | **Affected areas sink or are submerged in fixative |
| + | *Micro pathology: |
| + | **Close approximation of capillary walls |
| + | **Little normal alveolar pattern |
| + | **'Barkers' may have a proteinaceous fluid in alveoli with hyaline membranes in lower airways |
| + | *Cause: |
| + | **In weak neonates -inadequate respiratory effort or damage to the respiratory centres in the brain, aspiration of amniotic fluid or meconium |
| + | **In 'barkers'- defective production of surfactant by the Type 2 alveolar epithelium |
| + | *Foals that survive may have hypoxic damage to their brain, walk aimlessly and lack normal sense of fear - "wanderers" |
| + | |
| + | |
| + | ===Congenital lobar emphysema=== |
| + | |
| + | *See [[Bronchi and Bronchioles Developmental - Pathology#Congenital lobar emphysema|congenital lobar emphysema]] |
| + | |
| + | |
| + | ===Pulmonary hypoplasia=== |
| + | |
| + | *Mostly associated with [[Peritoneal cavity - developmental#Pleuroperitoneal diaphragmatic hernia|congenital diaphragmatic hernia]] |
| + | |
| + | |
| + | ===Congenital alveolar dysplasia=== |
| + | |
| + | *Most common in dogs |
| + | *Grossly: |
| + | **Lungs retain fetal appearance and are poorly aerated |
| + | *Histologically: |
| + | **Uneven size and shape of alveoli, smaller number overall |
| + | **Dilated blood vessels within extensive interstitial tissue |
| + | *It is possible that in utero infection may contribute to this |