Diagnostic contribution of thoracic ultrasonography in 17 foals with Rhodococcus equi pneumonia

The aim of this retrospective study was to determine the clinical usefulness of thoracic ultrasonography compared to thoracic radiography in evaluation of Rhodococcus equi pneumonia. Criteria for patient inclusion in this study were: (1) isolation of R. equi from transtracheal aspirate, (2) radiographic evaluation of the pulmonary parenchyma, and (3) sonographic evaluation of the pulmonary parenchyma. Seventeen foals met this criteria and their medical records were reviewed. Pyogranulomatous pneumonia was identified radiographically in 13 foals. Severe consolidative pneumonia with no detectable abscessation was identified radiographically in three others. Both consolidation and abscessation were identified radiographically in one. In this foal only consolidation was ultrasonographically identified. Ultrasonographically, pulmonary abscessation was identified in 12 foals and pulmonary consolidation with no detectable abscessation was identified in three others. Sonographic examination allowed detection of only pleural irregularities in one foal, which was subsequently found to have pyogranulomatous pneumonia radiographically. Results indicate that ultrasonography may be an accurate alternative imaging modality for detection of pulmonary pathology attributed to R. equi pneumonia in foals when thoracic radiography is not available.     

Rhodococcus equi pneumonia in an adult horse

A 20‐year‐old, Thoroughbred mare in the fifth month of gestation was examined for weight loss, pyrexia and lethargy. Physical examination, ultrasonography and radiography revealed a severe abscessing pneumonia and a dead fetus. The mare did not respond to symptomatic treatment and died suddenly. Necropsy revealed multifocal pulmonary abscessation. Rhodococcus equi was isolated from the lungs, liver and kidneys. Specific immune function of the mare and presence of the virulence associated protein A (VapA) of the R. equi isolated was not determined. It is likely that immunosuppression is required for systemic R. equi infections in adult horses; however, it is unknown if VapA is necessary to produce disease in adult horses.     

The Pathogenesis of Reactive Systemic Amyloidosis

The diagnosis of amyloidosis is based on the presence of extracellular tissue deposits of proteinaceous material that demonstrate a characteristic green color when stained with Congo red and viewed under polarized light. Several different proteins are amyloidogenic but, in domestic animals, spontaneously occurring systemic amyloidosis is reactive in nature and characterized by the presence of amyloid protein AA. This type of systemic amyloidosis may occur secondary to chronic inflammatory or neoplastic disease, but in many instances no predisposing disease is found. A sustained increase in the serum concentration of serum amyloid A protein (SAA) is necessary but not sufficient for the development of reactive amyloidosis. Other inherited and acquired host-related factors are likely to be important in the development of reactive amyloidosis because this condition develops in few patients with chronic inflammatory disease. The tissue tropism of amyloid deposits varies with the amyloid protein itself and species affected. The consequences of amyloidosis for the host depend upon the tissues involved and the response of these tissues to the presence of the amyloid deposits. In domestic animals, reactive systemic amyloidosis is nephropathic, leading to end-stage renal disease, and the clinical presentation is that of uremia.     

Immunohistochemical distribution of amyloid deposits in 25 cows diagnosed with systemic AA amyloidosis

The distribution of amyloid deposits was histopathologically and immunohistochemically examined in 25 cows aged 5 to 10 years that had been diagnosed with systemic AA amyloidosis. This examination revealed that amyloid deposits were also present in the hypophysis, ovary, uterus, mammary gland and skeletal muscle, in addition to the liver, kidney, spleen, pancreas, thyroid gland, adrenal gland, gastrointestinal mucosa, heart, lung and lymph nodes. The examined cows tended to have chronic inflammations, including chronic mastitis (six cases) or chronic pneumonia (four cases), which is thought of as a causative agent of AA amyloidosis. In contrast, five cases did not exhibit any chronic inflammation.     

Osteomyelitis of the hyoid bones in two calves

Two calves were referred because of ptyalism and difficulty opening the mouth (Calf 1) and for elective umbilical hernia surgery under inhalation anaesthesia (Calf 2). Additional clinical signs were increased breath sounds and swelling in the region of the mandibular angle in Calf 1. Ultrasonography and endoscopy revealed oral inflammation and abscessation in the area of the base of the tongue in both calves. Infection of the hyoid apparatus was suspected based on ultrasonographic findings and confirmed by means of computed tomography. In Calf 1, there was no response to treatment with systemic antibiotics, nonsteroidal anti-inflammatory drugs and local lavage, and Calf 2 was not treated. Both calves were euthanized because of a poor prognosis and the diagnoses confirmed during postmortem examination. In Calf 1, the abscess was associated with complete destruction of the left epihyoid bone and partial destruction of the left stylohyoid and ceratohyoid bones. In Calf 2, the abscess was located at the distal end of the right stylohyoid bone near the epihyoid bone. Stomatitis or laryngeal and pharyngeal abscessation caused by sharp feed particles are common in cattle and infection of the hyoid apparatus should be included in the differential diagnosis.     

Haemodynamic response to exercise in Standardbred trotters with red cell hypervolaemia

In order to evaluate the haemodynamic response to exercise in Standardbred trotters with red cell hypervolaemia (RCHV), 12 trotters with RCHV were compared with 9 normovolaemic (NV) trotters. Haemodynamic data were recorded during exercise at 4 different speeds on a treadmill. Oxygen uptake was determined with an open bias flow system. Pulmonary artery pressure (PAP), systemic artery pressure (SAP), heart rate, packed cell volume (PCV) and plasma lactate and haemoglobin ([Hb]) concentrations were measured. Arteriovenous O2 content difference, cardiac output, stroke volume, pulmonary vascular resistance (PVR) and total systemic resistance (TSR) were calculated. Oxygen uptake, arteriovenous O2 content difference, heart rate, cardiac output, stroke volume, TSR and lactate did not differ between groups. The RCHV horses had significantly higher both mean diastolic and systolic PAP compared to NV horses and this difference increased with higher workload. Further, a higher SAP, PVR, PCV and [Hb] were found in RCHV horses during the course of exercise. Eleven of the RCHV horses, but none of the NV, showed exercise-induced pulmonary haemorrhage on endoscopic examination. The increase in red cell volume, resulting in a high PCV and high total blood volume, is suggested to be an important contributor to both the increased blood pressures in pulmonary and systemic circulation during exercise and to the development of exercise-induced pulmonary haemorrhage in RCHV horses.     

Transthyretin amyloidosis and two other aging-related amyloidoses in an aged vervet monkey

An aged male vervet monkey showed severe cardiac arrhythmia for more than 3 years. A multifocal amyloid consisting of transthyretin was deposited in all areas of the heart wall, especially in the extracellular stroma among muscle fibers and external tunica of arterioles. Moreover, the amyloid was deposited in the stroma and arterioles of other systemic organs except the liver and spleen. These characteristics are consistent with senile systemic amyloidosis in humans. A second amyloid consisting of amyloid beta protein was in senile plaques and cerebral amyloid angiopathy in the cerebral cortex. A third amyloid consisting of islet amyloid polypeptide was deposited in islets of the pancreas. Apolipoprotein E and amyloid P component colocalized with the 3 amyloids. Thus, 3 different aging-related amyloids were found in an aged vervet monkey. In particular, to our knowledge, this is the first report on spontaneous transthyretin amyloidosis in animals.     

Amyloidosis in six dairy cows

Amyloidosis was diagnosed in 6 Holstein cows that were examined because of chronic intractable diarrhea. Besides diarrhea, the chief finding was a nephrotic-like syndrome, in that there was edema, hypoproteinemia, and proteinuria. Other consistent clinicopathologic abnormalities were hyperfibrinogenemia, low-normal serum calcium content or hypocalcemia, hypomagnesemia, prolonged bromosulphalein half time, high serum urea nitrogen concentration, high serum creatinine concentration, and low urine specific gravity. Foci of inflammation including traumatic reticuloperitonitis, traumatic pericarditis, salpingitis, mastitis, and metritis were found. There was histologic evidence of amyloid in the kidneys, liver, adrenal glands, and spleen. The iodine-sulfuric acid test for amyloid was positive in 2 cows. The Congo red dye test for amyloid was positive in 2 other cows. In spite of supportive care, all the cows either died naturally or were euthanatized. Because foci of inflammation were found in each cow, it was concluded that the most likely classification of amyloidosis in these cases would be reactive systemic amyloidosis and that the major amyloid fibril protein would be type AA.     

Review of Corynebacterium (Rhodococcus) equi lung abscesses in foals: pathogenesis, diagnosis and treatment

Corynebacterium (Rhodococcus) equi is becoming increasingly significant as a cause of bronchopneumonia and lung abscessation in foals. The organism can survive within macrophages and may thus escape normal pulmonary defence mechanisms, particularly in immunocompromised animals. The disease has hitherto been associated with mortality rates as high as 80 per cent, partly as a result of inappropriate therapy. The selection of lipid-soluble antibiotics capable of intracellular penetration is critical for the successful treatment of C equi lung abscesses. A combination of two such antibiotics, erythromycin (25 mg/kg three times daily) and rifampicin (5 mg/kg twice daily) has been used on foals since 1981. Most of these animals had radiographic evidence of extensive lung abscessation, and in all cases the presence of C equi was confirmed on culture of tracheal aspirates. The duration of therapy ranged from four to nine weeks. Mild gastritis and diarrhoea were occasionally noted, but never such as to require termination of the therapy. No other adverse side effects were encountered. The success rate, as judged by a return to normal of chest radiographs and plasma fibrinogen concentrations, has exceeded 80 per cent.     

Brain abscess and bacterial endocarditis in a Kerry Blue Terrier with a history of immune-mediated thrombocytopenia

Objective: To describe a case of multifocal brain abscessation as a sequela from bacterial endocarditis in a dog with a 4‐month history of immune‐mediated thrombocytopenia (ITP) and treatment with immunosuppressive therapies. Case summary: An 8‐year‐old spayed female Kerry Blue Terrier weighing 13 kg was presented for evaluation of progressive neurologic deficits after a 4‐month history of immunosuppressive treatment of ITP. Brain magnetic resonance imaging revealed lesions consistent with multiple central nervous system abscesses and rupture of an abscess into an adjacent ventricle. Staphylococcus species were cultured from blood and cerebral spinal fluid and a vegetative lesion of the mitral valve was identified by echocardiographic examination. Intensive care, intravenous antibiotics, and supportive therapy led to resolution of clinical signs. Resolution of the vegetative lesion on the mitral valve was documented by serial echocardiographic examination. The dog was clinically normal 11 months after treatment. New or unique information provided: Bacterial endocarditis can be an occult infection and difficult to diagnose. Emboli from endocarditis are common, but those that affect the spleen and kidneys are often clinically silent in dogs. This case represents the first report of multifocal brain abscessation (documented with magnetic resonance imaging) as a sequela from bacterial endocarditis.     

Survey of the Large Animal Diplomates of the American College of Veterinary Internal Medicine Regarding Percutaneous Lung Biopsy in the Horse

A survey designed to obtain information on the indications, contraindications, complications, and methodology of percutaneous lung biopsy in the horse was sent to large animal diplomates of the American College of Veterinary Internal Medicine. Sixty-five of 190 diplomates returned the survey (response rate: 34%) and 59 of these 65 respondents (91%) indicated that they worked with horses. Forty-four diplomates had performed a percutaneous lung biopsy in 1 or more horses (ie 75% of those diplomates working with horses and 68% of total respondents). Clinical and radiologic diagnoses that prompted diplomates to perform percutaneous lung biopsy in the horse included a pulmonary miliary pattern (93%), suspicion of pulmonary infiltrative disease (91%), suspicion of pulmonary neoplasia (91%), suspicion of chronic obstructive pulmonary disease (COPD) (20%), and suspicion of exercise-induced pulmonary hemorrhage (EIPH) (7%). Only one of the respondents reported the use of percutaneous lung biopsy in the diagnostic workup if pneumonia was suspected, but 11% of respondents reported that suspicion of pulmonary abscessation would prompt them to perform a percutaneous lung biopsy. In contrast, a variable percentage of respondents felt there were contraindications to performance of this technique, which included neonatal septicemia (68%), pulmonary abscessation (65%), pleuropneumonia (55%) and pneumonia (42%), EIPH (41%), and COPD (26%). No respondent indicated that suspicion of neoplasia was a contraindication to percutaneous biopsy. Most common complications observed by respondents were epistaxis (68% of respondents), putative pulmonary hemorrhage (52%), tachypnea (39%), and respiratory distress (32%). Ten of 44 respondents (23%) had not seen any complications with percutaneous lung biopsy. Forty-two of 44 respondents (96%) warned owners about possible complications before performing percutaneous lung biopsy. All respondents to this question reported that they would perform percutaneous lung biopsies in horses in the future, but 4 of 41 would use the procedure only as a last resort.     

Septic epiglottic chondritis with abscessation in 2 young Thoroughbred racehorses

Septic epiglottic chondritis with abscessation diagnosed in 2 Thoroughbred racehorses. Infected cartilage removed videoendoscopically followed by systemic antibiotics. The infectious process was successfully controlled, but permanent dorsal displacement of the soft palate (DDSP) with a shortened, deformed epiglottic cartilage developed. Surgery for the DDSP using bilateral partial sternothyroidectomy or laryngeal tie-forward failed.     

Morbidity and mortality associated with Arcanobacterium pyogenes in a group of captive blackbuck (Antilope cervicapra).

Arcanobacterium pyogenes was associated with necrotizing pneumonia; mandibular osteomyelitis; peritonitis; and hepatic, pulmonary, renal, and subcutaneous abscessation in a group of captive blackbuck (Antilope cervicapra). Males were more frequently (73.3%) affected than females. Infection with A. pyogenes was fatal or necessitated euthanasia in 15 of 16 (93.7%) cases. Deaths associated with A. pyogenes occurred most frequently (60%) during winter.     

HEPATIC ABSCESSES IN 13 DOGS: A REVIEW OF THE ULTRASONOGRAPHIC FINDINGS, CLINICAL DATA AND THERAPEUTIC OPTIONS

Historical, physical examination, clinicopathologic, radiographic and ultrasonographic findings of 13 dogs with hepatic abscesses were reviewed. Liver abscessation was characterized by number, size, shape, echogenicity and location. Solitary lesions greater than 3 cm were more common than multiple ones. The abscesses were mainly poorly echogenic lesions, often with central cavitation. The shape of the lesion ranged from round to oval or irregular. Enhancement artifact, abdominal effusion, regional lymphadenopathy and hyperechoic perihepatic fat, were identified in several dogs. Ultrasound-guided aspiration was performed in 10 of 13 dogs, and confirmed abscessation with cytologic and microbiologic evaluation. Ultrasound-guided percutaneous drainage of abscesses was performed as an adjunct to medical management in four dogs.     

Angiostroneylosis in Cornwall: Clinical presentations of eight cases

Clinical signs in eight dogs with Angiostrongylus vasorum infection included chronic cough, dyspnoea, lumbar pain, hindleg paresis/paralysis, abdominal pain, weakness and collapse; two of the dogs were asymptomatic. Thrombocytopenia was present in two dogs and a mild anaemia in one. Thoracic radiographs showed mild right heart enlargement in two out of three dogs and a pneumothorax in one. At post mortem examination in three dogs, the lungs were swollen with a mottled appearance and there was dilatation of the right ventricle. Adult A vasorum were found in the right heart, the pulmonary artery and its branches. Adult worms were also found in the systemic vasculature in one dog, associated with thromboembolism. Treatment with ivermectin in two dogs and fenbendazole in three dogs resulted in the resolution of clinical signs and no demonstrable larvae in the faeces one to two weeks later.     

Ultrasonography as a diagnostic aid in horses with anaerobic bacterial pleuropneumonia and/or pulmonary abscessation: 27 cases (1984-1986)

The medical records of 83 horses with pleuropneumonia and/or pulmonary abscessation, in which thoracic sonography was used, were reviewed. The sonograms of these horses were reviewed retrospectively for free gas echoes within pleural or abscess fluid. Anaerobic infection was confirmed in 27 horses, and gas echoes were observed in 21 horses. There was a significant (P less than 0.001) correlation between the observation of gas echoes and anaerobic infection in horses with pleuropneumonia and/or pulmonary abscessation. A foul odor to the breath or pleural fluid was significantly (P less than 0.001) associated with anaerobic infection. Poor survival rates were associated with gas echoes or a foul odor to the breath or pleural fluid, both of which were associated with anaerobic infection. Gas echoes within pleural or abscess fluid were found to be a sensitive and specific indicator of anaerobic infection, as was a putrid odor to the breath or pleural fluid. Evaluation for gas echoes and foul odor had better predictive value than did evaluation for gas echoes or foul odor alone. Gas echoes within pleural or abscess fluid is highly suggestive of anaerobic infection. Ultrasonography should be performed repeatedly in horses with pleuropneumonia to assess the progression or resolution of pleural and parenchymal disease. The detection of gas echoes on subsequent ultrasonograms may indicate the development of anaerobic infection.     

Necrobacillary bronchopneumonia in a steer.

A one and one-half year old steer killed in a slaughterhouse had necrobacillary fibrinous bronchopneumonia with abscessation. Histologically, there were variably sized areas of coagulation necrosis in the lungs, thrombosis of pulmonary lymphatics, and fibrin deposits in the bronchioli and adjacent alveoli. Fusobacterium necrophorum in pure culture was isolated from the lung.     

Acute onset of pulmonary necrotising arteritis in a dog with a left-to-right patent ductus arteriosus

A 12-week-old, clinically normal Chihuahua was referred for investigation for a continuous heart murmur. Cardiac evaluation revealed an anatomically and haemodynamically typical left-to-right shunting patent ductus arteriosus. The continuous wave Doppler measurement of peak ductal jet velocity of 5.6 m/s was suggestive of a normal pulmonary to systemic arterial pressure ratio. The dog returned 16 days later with right heart failure and severe pulmonary hypertension. Marked reduction in left-to-right shunting was demonstrated and the ductal jet velocity had decreased to 2.5 m/s. Immediate ductus ligation, oxygen therapy before and after the operation, and administration of hydralazine failed to reduce pulmonary hypertension, and the dog was euthanased. Histopathological examination of the lung showed pulmonary necrotising arteritis with acute and chronic arterial lesions. Chronic pulmonary vascular changes related to high flow have been associated with altered nitric oxide and endothelin responses. These changes may be responsible for the acute onset of pulmonary hypertension due to relatively minor vascular insults in some human and veterinary patients with left-to-right shunts. The potential for acute progression supports the recommendations for early ductus ligation and the prognostic importance of detecting pulmonary hypertension presurgically in patent ductus arteriosus patients.