OVERVIEW
Respiratory enteric orphan virus (reovirus)—genus in the family Reovirus; nonenveloped, double-stranded RNA virus; isolated from respiratory and enteric tracts; not associated with any known disease (hence orphan)
Ubiquitous in geographic distribution and host range, virtually every species of mammal, including humans
Virus—infects mature epithelial cells on luminal tips of the intestinal villi; causes cellular destruction, resulting in villous atrophy (similar to rotavirus and coronavirus)
Loss of absorptive capability and loss of brush border enzymes (e.g., disaccharidases) leads to osmotic diarrhea.
Tuesday, March 29, 2011
Q Fever
OVERVIEW
Caused by the zoonotic rickettsia Coxiella burnetii
Infection—most commonly by inhalation or ingestion of organisms while feeding on infected body fluids (urine, feces, milk, or parturient discharges), tissues (especially placenta), or carcasses of infected animal reservoir hosts (cattle, sheep, goats); can occur after tick exposure (many species of ticks implicated)
Lungs—thought to be main portal of entry to systemic circulation
Organism replicates in vascular endothelium; causes widespread vasculitis; severity depends on the pathogenicity of the strain of organism; vasculitis results in necrosis and hemorrhage in lungs, liver, and CNS
An extended latent period exists after recovery until chronic immune-complex phenomena develop; organism reactivated out of the latent state during parturition, resulting in large numbers entering the placenta, parturient fluids, urine, feces, and milk
Endemic worldwide
Caused by the zoonotic rickettsia Coxiella burnetii
Infection—most commonly by inhalation or ingestion of organisms while feeding on infected body fluids (urine, feces, milk, or parturient discharges), tissues (especially placenta), or carcasses of infected animal reservoir hosts (cattle, sheep, goats); can occur after tick exposure (many species of ticks implicated)
Lungs—thought to be main portal of entry to systemic circulation
Organism replicates in vascular endothelium; causes widespread vasculitis; severity depends on the pathogenicity of the strain of organism; vasculitis results in necrosis and hemorrhage in lungs, liver, and CNS
An extended latent period exists after recovery until chronic immune-complex phenomena develop; organism reactivated out of the latent state during parturition, resulting in large numbers entering the placenta, parturient fluids, urine, feces, and milk
Endemic worldwide
Pulmonary Mineralizations
OVERVIEW
Both calcification and ossification and may be generalized or localized
Discrete—if individual mineral deposits can be identified
Diffuse—preclude identification of individual deposits
Calcification—dystrophic or metastatic; dystrophic: occurs secondary to tissue degeneration or inflammation; metastatic: occurs secondary to metabolic disease; may be normal (e.g., the pleura in old dogs or premature calcification of the tracheal and bronchial cartilages in chondrodystrophic breeds); often a sign of inactivity of a lesion, thus most focal calcifications are functionally unimportant
Ossification—also called heterotopic bone formation; calcification of a bony matrix; pulmonary ossification in the form of small, multiple nodules (osteomas) common in normal dogs
Generalized pulmonary mineralizations of unknown cause—reported in dogs and cats under descriptive terms: pulmonary alveolar microlithiasis or pumice stone lung, bronchiolar microlithiasis, idiopathic pulmonary calcification or ossification
Both calcification and ossification and may be generalized or localized
Discrete—if individual mineral deposits can be identified
Diffuse—preclude identification of individual deposits
Calcification—dystrophic or metastatic; dystrophic: occurs secondary to tissue degeneration or inflammation; metastatic: occurs secondary to metabolic disease; may be normal (e.g., the pleura in old dogs or premature calcification of the tracheal and bronchial cartilages in chondrodystrophic breeds); often a sign of inactivity of a lesion, thus most focal calcifications are functionally unimportant
Ossification—also called heterotopic bone formation; calcification of a bony matrix; pulmonary ossification in the form of small, multiple nodules (osteomas) common in normal dogs
Generalized pulmonary mineralizations of unknown cause—reported in dogs and cats under descriptive terms: pulmonary alveolar microlithiasis or pumice stone lung, bronchiolar microlithiasis, idiopathic pulmonary calcification or ossification
Proteinuria
DEFINITION
A subjective increase in urinary protein detected by dipstick analysis; objectively, a urinary protein:creatinine ratio > 1 or a 24-h urinary protein content > 20 mg/kg
PATHOPHYSIOLOGY
Greater than normal delivery of low-molecular-weight plasma proteins to the glomerulus
Excessive leakage of proteins across the glomerular basement membrane secondary to altered permselectivity of the glomerulus
Reduced tubular reabsorptive capacity for proteins, or exudation of blood or serum into the lower urinary tract
A subjective increase in urinary protein detected by dipstick analysis; objectively, a urinary protein:creatinine ratio > 1 or a 24-h urinary protein content > 20 mg/kg
PATHOPHYSIOLOGY
Greater than normal delivery of low-molecular-weight plasma proteins to the glomerulus
Excessive leakage of proteins across the glomerular basement membrane secondary to altered permselectivity of the glomerulus
Reduced tubular reabsorptive capacity for proteins, or exudation of blood or serum into the lower urinary tract
Potassium, Hypokalemia
DEFINITION
Serum potassium concentration < 3.5 mEq/L
PATHOPHYSIOLOGY
Potassium is the major intracellular cation and thereby largely responsible for maintenance of intracellular volume.
The ratio of intracellular to extracellular potassium concentration is important in determining the cellular membrane potential. Rapid alterations in extracellular potassium concentration alter this ratio and predispose an animal to arrhythmias and conduction disturbances in excitable tissues (e.g., heart, nerve, and muscle)
Hypokalemia can be caused by excessive potassium loss via the gastrointestinal tract or kidneys or movement of potassium from the extracellular fluid compartment into cells (i.e., translocation).
Serum potassium concentration < 3.5 mEq/L
PATHOPHYSIOLOGY
Potassium is the major intracellular cation and thereby largely responsible for maintenance of intracellular volume.
The ratio of intracellular to extracellular potassium concentration is important in determining the cellular membrane potential. Rapid alterations in extracellular potassium concentration alter this ratio and predispose an animal to arrhythmias and conduction disturbances in excitable tissues (e.g., heart, nerve, and muscle)
Hypokalemia can be caused by excessive potassium loss via the gastrointestinal tract or kidneys or movement of potassium from the extracellular fluid compartment into cells (i.e., translocation).
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