Acute respiratory distress syndrome (ARDS) in lambs. Hematology

Lambs suffering from Acute Respiratory Distress Syndrome (ARDS) showed elevated PCV, neutrophilia, a tendency towards lymphopenia, eosinopenia, hyperphosphatemia, hypoglycemia and extremely low serum Ca values during the first couple of days after the outbreak of symptoms. During the very early phase, plasma potassium values were mostly lowered (Figs. 1-3, Table I). The possible involvement of histamine is shortly discussed: either 1) through an atopic reaction, 2) because of acute ruminal acidosis and sudden histamine formation, or 3) involvement of endotoxins.     

Acute respiratory distress syndrome (ARDS) in lambs. Clinical and pathoanatomical investigations

In the South-Western part of Norway, lambs of the Old Norwegian short tailed breed (Spael) and crosses with the Dala breed sometimes develop an Acute Respiratory Distress Syndrome (ARDS) shortly after they have been moved onto lush aftermath grazings from mountain pastures. This article covers the symptoms and pathoanatomical findings in lambs affected with ARDS (Table I). The lambs acquired ARDS 18-72 hours after change of pasture. Heavy dysphne, frothing at the mouth, elevated temperature (greater than 41 degrees C), tachycardia, urination and ruminal atony were striking symptoms (Table II). In the early phase of the disease the lambs were often in a tranquil state, depressed, sometimes atactic, and it seemed that they went into the overt dysphneic phase on exposure to physical stress. Morbidity was 1.4%, mortality 36%. Post mortem findings included frothy contents in the airways, heavy congestion and oedema in the lungs which also had emphysematous areas, subepicardial petechiae, varying degree of mottling of the myocardium, and also varying degree of paleness and spottyness of renal cortices. The lungs showed extensive focal alveolar and interstitial emphysema, septal congestion, alveolar oedema, partial collapse, and accumulations of polymorphonuclear leucocytes in vascular beds. Later, fibrillar material was found in the alveoli, alveolar macrophages accumulated, and interalveolar septa thickened because of increased fibromuscular tissue and mononuclear cells (Fig. 1, A-D). Alveolar epithelial hyperplasia was not seen in any stage. Four lambs were moderately infected with lungworms (D. filaria), three in the prepatent, one in the patent phase. Histopathological changes in other organs included granular degenerations of myocardial threads, and development of a glomerulonephritis and focal interstitial nephritis (Fig. 1, E-F). This disease entity (ARDS) in lambs seems to be unknown in literature. The disease is compared with other known diseases in ruminants. Etiology is so far unknown. Possibilities of sudden ruminal histamine formation coinciding with a hypersensitivity reaction is discussed.     

Acute respiratory distress syndrome in dogs and cats: a review of clinical findings and pathophysiology

Objective: To review the clinical and pathophysiologic aspects of acute respiratory distress syndrome (ARDS) in dogs and cats. Data sources: Data from human and veterinary literature were reviewed through Medline and CAB as well as manual search of references listed in articles pertaining to acute lung injury (ALI)/ARDS. Human data synthesis: Since the term ARDS was first coined in 1967, there has been a abundance of literature pertaining to this devastating syndrome in human medicine. More complete understanding of the complex interactions between inflammatory cells, soluble mediators (e.g., tumor necrosis factor, interleukin (IL)‐6, IL‐8, platelet activating factor) and the clinical patient has provided for timely recognition and mechanistically based protective strategies decreasing morbidity and mortality in human patients with ARDS. Veterinary data synthesis: Although little is known, ARDS is becoming a more commonly recognized sequela in small animals. Initial case reports and retrospective studies have provided basic clinical characterization of ARDS in dogs and cats. Additionally, information from experimental models has expanded our understanding of the inflammatory mechanisms involved. It appears that the inflammatory processes and pathologic changes associated with ARDS are similar in dogs, cats, and humans. Conclusions: Unfortunately, current mortality rates for ARDS in small animals are close to 100%. As our capability to treat patients with advanced life‐threatening disease increases, it is vital that we develop a familiarity with the pathogenesis of ARDS. Understanding the complex inflammatory interactions is essential for determining effective preventative and management strategies as well as designing novel therapies for veterinary patients.     

3-Methylindole-induced pulmonary injury in lambs. A comparison with acute respiratory distress syndrome (ARDS)

Five to six month-old lambs of two different Norwegian breeds (Dala and Rygja) were dosed with 3-methyl indole (3MI) and DL-tryptophan (DL-T), and examined clinically, hematologically and post mortem. Results were compared with the findings in Acute Respiratory Distress Syndrome (ARDS), a condition of acute dyspnea occurring in 5-6 month-old lambs (of Dala and Spael breeds) after they have been moved from mountain pastures onto lush aftermath in September. The results show that such young Norwegian lambs are susceptible to 3MI-dosing, and that the symptoms and lesions were similar to those described earlier in connection with 3MI-dosing in cattle and adult sheep. The results clearly demonstrate that 3-MI-induced pulmonary injury in lambs differs from ARDS as far as both symptoms, hematology and pathology are concerned.     

Negative-pressure pulmonary edema complicated by acute respiratory distress syndrome in an orangutan (Pongo pygmaeus abelii).

A 22-yr-old, 86-kg, morbidly obese female orangutan (Pongo pygmaeus abelii) was immobilized and transported to the Denver Zoological Gardens hospital for a routine physical examination. Immediately after arriving at the hospital, cyanosis and apparent inadequate ventilatory efforts were noted. Clinically significant hypoxia occurred despite attempts to ventilate the orangutan through face mask, and attempts to place an endotracheal tube began. A large volume of pink-tinged frothy fluid flowed from the trachea when the laryngoscope was inserted into the oropharynx. Severe pulmonary edema due to negative-pressure pulmonary edema, precipitating life-threatening hypoxia was suspected. The orangutan was maintained on a mechanical ventilator using the neuromuscular blocking agent cisatracurium besylate and sedation with periodic doses of isoflurane and midazolam for 48 hr. Positive end-expiratory pressure was used while the orangutan was ventilated mechanically to improve respiratory function. The edema and hypoxia improved, but respiratory arrest ensued 30 min after extubation, when the orangutan was removed from mechanical ventilation. Necropsy and histopathology demonstrated that serious lung injury had led to acute respiratory distress syndrome.     

Bovine respiratory disease: pathogenesis, clinical signs, and treatment in lightweight calves.

No matter what disease is being addressed, there are basic steps required for successful therapy. Failure to address each step systematically leaves a gap in the program that eventually shows up as inconsistency or failure in therapeutic efficacy. The focus in this article is on applying these steps in infectious bovine respiratory disease challenges in lightweight stocker calves.     

The pathomorphology and pathogenesis of acute cardiovascular failure in swine. 2. Histopathologic findings in the myocardium of swine of different populations

Histopathological alterations of the myocardium (inflammatory processes, fibrolysis, fibronecrosis, dystrophic calcification, fatty degeneration of fibres, sarcosporidia) were recorded for quantitative evaluation from 200 hearts which had been collected from clinically intact pigs for slaughter of different populations (Leicoma, land race, Schwerfurt breed, Belgian land race). Both incidence and severity of myocardial damage in pigs of stress-sensitive populations were higher with significance than those in the less stress-sensitive Leicoma population oriented to breeding. The highest rate of pathological processes was recorded from hearts of the Schwerfurt breed. These alterations were interpreted as objectively measurable expressions of breed-dependent differences in cardiovascular stability. In this context, rates of damage were higher in hearts of low absolute mass.     

The pathomorphology and pathogenesis of acute cardiovascular failure in swine. 1. Histopathologic findings in the myocardium of swine of different age groups

Myocardia were histologically examined for the presence of pathomorphological processes in 143 pigs of varying age groups (one, three, seven to nine, and 24 months). Some of them had been slaughtered in clinically intact condition. Others had died of non-cardial diseases. Numerous alterations were recorded, with the following among them being more suitable than others for quantitative assessment and thus objective appraisal of the myocardium: inflammatory infiltrations, granular or hyaline disintegration of fibres, fibre necrosis, dystrophic calcification of fibres, degenerative fat infiltration, and sarcosporidiosis. These parameters were increasingly detectable along with growing age of animals. Inflammatory infiltrations were among the most common findings from pigs for slaughter, aged seven to nine months (40.4 percent of myocardial samples or 58 percent of hearts), followed by muscle fibre necroses (26.4 or 42.0 percent). Most of these disorders were but slightly manifest and were considered to be indicators of catabolic or reparative processes in the myocardium. Attention should be given to them, whenever it comes to pigs with cardiac or circulatory disturbances.     

The pathomorphology and pathogenesis of acute cardiovascular failure in swine. 3. Histopathologic findings in the myocardium of swine with transport-related cardiovascular insufficiency

Quantitative pathohistological investigations were performed on 300 samples of five different myocardial regions from 50 pigs with had suffered stress-related myocardial insufficiency on their transport to the slaughterhouse (transport exhaustion). The findings were compared to 1,200 myocardial samples from 200 clinically intact pigs for slaughter. Animals with transport-related damage exhibited with significance more and more severe inflammatory and degenerative myocardial alterations, such as round-cell infiltration, fiber necrosis, calcification, and fat infiltration. Many of these lesions had been manifest already prior to transport. Myocardially predamaged pigs were less capable than others of sustaining transport stress and were more predisposed to cardiac failure. Stress-related cardiovascular insufficiency, consequently, depended not only on direct stress but also on the general health condition of the myocardium. Causes and pathogenetic relevance of these alterations are discussed in some detail.     

Observations on outbreaks of respiratory disease in housed calves--(1) Epidemiological, clinical and microbiological findings.

In 47 of 50 outbreaks of respiratory disease in indoor calves which had never been to grass there was clinical evidence of pneumonia in all animals examined. Calf housing was in most cases considered unsatisfactory. Virus activity was detected in 70 per cent of outbreaks investigated within a few days post onset of respiratory signs. Parainfluenza (PI) 3 and respiratory syncitial virus (RSV) were the viruses most frequently involved. In the majority of outbreaks Mycoplasma species and Pasteurella multocida were present in the upper respiratory tract of affected calves.     

A review of porcine reproductive and respiratory syndrome virus in Dutch breeding herds: population dynamics and clinical relevance

Understanding the spread of porcine reproductive and respiratory syndrome virus (PRRSV) in pig populations is essential to the development of effective PRRS prevention and control strategies. Moreover, knowledge of the field dynamics of PRRSV in pigs will provide insights into the clinical relevance of PRRS, and will enable the targeting of interventions. This review of PRRSV includes discussion on the occurrence of outbreaks, the persistence of infection and the fade-out of infection in Dutch breeding herds. The dynamic character of PRRSV infections in endemically infected herds and the relevance of the disease under Dutch field conditions are also highlighted. Furthermore, several strategies aimed at controlling the spread of PRRSV are discussed.