Botox for Horse Joint Pain?

Hello, Summarians!

Pain control is a big deal. I’m intrigued to see all the research that we can share across all species. Originally Botox was used in humans for refractory pain and has shown some success in other animals as well.

Please give me feedback on ways I can make it more useful to you.

If it is valuable to you please consider sending it on to a friend 😄 

Diagnosis of Ascites Issues in Dogs

Nonhemorrhagic ascites (NHA) is characterized by fluid accumulation in the peritoneal cavity with a packed cell volume (PCV) of less than 10%. In dogs, right-sided congestive heart failure (CHF) is a common cause of NHA, but other conditions like neoplasia, hepatic failure, hypoalbuminemia, pancreatitis, chyloabdomen, uroabdomen, and septic peritonitis can also lead to NHA. Differentiating between cardiac (cNHA) and noncardiac (ncNHA) causes can be challenging due to overlapping symptoms. Cardiac magnetic resonance imaging (MRI) is considered the gold standard for identifying right-sided heart disease in humans, but it is complex and requires general anesthesia in veterinary medicine. Transthoracic echocardiography is the primary imaging modality for identifying right-sided heart disease in dogs, but it has limitations such as cost, specialized training, and availability. Cardiac biomarkers like N-terminal brain natriuretic peptide (NT-proBNP) and cardiac troponin-I (cTnI) are noninvasive and widely available, making them of interest for distinguishing causes of NHA. Point-of-care ultrasound (POCUS) has also been investigated as a potential tool for differentiating causes of NHA. A study compared NT-proBNP, cTnI, and POCUS in dogs with cNHA and ncNHA. The researchers hypothesized that NT-proBNP and cTnI concentrations would be significantly increased in dogs with cNHA compared to ncNHA and that NT-proBNP would be significantly increased in dogs with cardiac non-pericardial disease compared to pericardial disease. The study found that NT-proBNP concentrations could differentiate between cNHA and ncNHA. The specificity improved when dogs with pericardial disease were excluded, further distinguishing dogs with cardiac non-pericardial diseases from those with ncNHA. However, cTnI concentrations were not useful for distinguishing between cNHA and ncNHA. The study also evaluated POCUS findings and identified variables that could help differentiate cNHA from ncNHA. Hepatic venous and caudal vena cava (CaVC) distension were significantly associated with cNHA. Jugular distension, jugular pulsation, and the presence of a heart murmur were more common in dogs with cardiac non-pericardial disease compared to pericardial disease or ncNHA. However, the presence of a palpable fluid wave did not distinguish between cNHA and ncNHA. In conclusion, the study demonstrated that physical examination findings, NT-proBNP concentrations, and POCUS can be helpful in differentiating between cNHA and ncNHA in dogs. NT-proBNP was particularly useful in confirming underlying structural heart disease as the cause of NHA. However, it is important to consider these diagnostic tools in combination and not rely on them alone for a definitive diagnosis. 

Morey, AGN, Lamb, KE, Karnia, JJ, et al. N-terminal brain natriuretic peptide, cardiac troponin-I, and point-of-care ultrasound in dogs with cardiac and noncardiac causes of nonhemorrhagic ascites. J Vet Intern Med. 2023; 37( 3): 900- 909. doi:10.1111/jvim.16702 

Bottom line — NT-proBNP is useful to confirm structural heart issues in ascites cases

Botox for horse joint pain

In the year 2000, approximately one-third of domestic equids in the United States suffered from lameness due to osteoarthritis (OA), resulting in significant veterinary care expenses. The available therapies for OA were not ideal, and there was a need for more effective treatments. Botulinum neurotoxin type A (BoNT-A), which had been used in human medicine for various conditions, including refractory joint pain related to OA, showed promising results. Studies in horses and other animals suggested that intraarticular injections of BoNT-A could decrease pain and improve joint function. However, little was known about the direct effects of BoNT-A on articular cartilage. To address this, the objective of a recent study was to investigate the effects of BoNT-A on equine articular cartilage in vitro. The researchers used cartilage explants challenged with equine recombinant interleukin 1 (rEq IL-1) as a model for OA. They assessed various parameters related to cartilage matrix degradation, proteoglycan production, and the inflammatory response. The study hypothesized that BoNT-A would mitigate the catabolic and inflammatory effects of rEq IL-1 on articular cartilage in a concentration-dependent manner. However, the results did not support the hypothesis. BoNT-A treatment did not ameliorate the changes caused by rEq IL-1 challenge in the cartilage explants. The researchers also failed to disprove the null hypothesis that BoNT-A would have no concentration-dependent effects on cartilage matrix homeostasis and chondrocyte viability in unchallenged cartilage explants. The concentration range of BoNT-A used in the study was chosen to include the estimated clinically achieved synovial fluid concentration in horses. Although the study did not find quantifiable levels of collagen degradation in the media samples, it concluded that BoNT-A is likely safe for articular cartilage at the concentrations tested, as it did not have detrimental effects on cartilage matrix homeostasis or chondrocyte viability. However, it did not demonstrate disease-modifying or anti-inflammatory effects in the model used. The study had limitations, including its in vitro design, which did not consider the effects of treatment on other joint components, and the small number of horses used. The authors recommended further investigations to determine if BoNT-A has disease-modifying effects in vivo and to study its mechanism of action in equids with OA. In summary, the study did not find evidence to support the hypothesis that BoNT-A mitigates the effects of rEq IL-1 on equine articular cartilage in vitro. However, it indicated that BoNT-A may be safe for articular cartilage at the concentrations tested. Further research is needed to determine the potential disease-modifying and symptom-modifying effects of BoNT-A in equids with OA. 

McCarthy, M. B., Duesterdieck-Zellmer, K. F., & Larson, M. K. (2023). Botulinum neurotoxin type A does not exert concentration-dependent effects on equine articular cartilage in vitro, American Journal of Veterinary Research (published online ahead of print 2023). https://doi.org/10.2460/ajvr.23.04.0076 

Bottom line — Seems to be safe for cartilage but did not modify inflammation in this model. That may not be its mechanism of action for pain relief.

Error Rate for Veterinary Radioloigits

This passage discusses the importance of postmortem evaluations in medical education and hospital quality control, specifically focusing on radiologic evaluations in veterinary medicine. The study aims to quantify the radiologic error rate and identify the sources of discrepancies between radiologic and postmortem diagnoses. The passage highlights that while modern medical advancements have greatly improved antemortem diagnostic capabilities, postmortem evaluations remain valuable for assessing the accuracy of clinical diagnoses. Discrepancies between radiologic and postmortem autopsy diagnoses can occur due to various factors, including diagnostic errors and nonerror discrepancies. Nonerror discrepancies may involve lesion development or resolution over time, lesion obscuration by other diseases, or lesions too small to be detected by imaging. Radiologic errors, on the other hand, relate to the mistakes made by radiologists in identifying or interpreting lesions in imaging studies. The study's primary objective is to determine the radiologic error rate in a veterinary teaching hospital over a one-year period. The secondary objectives include identifying the most common sources of missed diagnoses, misinterpretations, and nonerror discrepancies. The study hypothesizes that the radiologic error rate in veterinary medicine would be similar to that reported in human studies. The passage also discusses specific findings from the study. It notes that the respiratory tract is the organ system most associated with discrepancies, with interstitial lung disease (ILD) being a common major diagnosis. ILD represents a group of diseases that affect the distal pulmonary parenchyma and can result in fibrosis and altered lung structure. While ILDs are well-characterized in human medicine, there is limited research on ILDs in veterinary medicine. The study population showed a similar frequency of primary ILD as reported in humans, but the low utilization of CT and lung biopsy in veterinary patients may contribute to infrequent antemortem ILD diagnoses. The passage also discusses the etiology of radiologic errors, categorizing them as either perceptual errors (missed diagnoses) or cognitive errors (misinterpretations). Perceptual errors in the study were mainly due to satisfaction of search error, where lesions were overlooked after identifying other abnormalities. Cognitive errors included biases such as framing bias, attribution bias, premature closure bias, and alliterative bias. The passage suggests that reducing errors requires considering both systematic causes (e.g., high workload, computer-related failures) and cultural causes (e.g., frequent interruptions, reluctance to share mistakes) and implementing strategies like systematic interpretation approaches and peer learning conferences. The study has limitations, including its retrospective nature and reliance on reported descriptions, archived materials, and photographs. Hindsight bias and selection bias in the autopsy cases are also acknowledged. Nevertheless, the study emphasizes the value of routine necropsy in auditing the accuracy of diagnostic imaging and highlights the occurrence of radiologic errors in veterinary medicine, with a reported error rate of 4.6%, similar to rates reported in human radiology literature. In summary, the passage discusses the importance of postmortem evaluations, particularly radiologic evaluations, in veterinary medicine. It highlights the objectives and findings of a study aiming to quantify the radiologic error rate and identify the causes of discrepancies between radiologic and postmortem diagnoses. 

Cohen, J, Fischetti, AJ, Daverio, H. Veterinary radiologic error rate as determined by necropsy. Vet Radiol Ultrasound. 2023; 64: 573– 584. https://doi.org/10.1111/vru.13259 

Bottom line — 4.6% error rate — similar to human radiologists

Just putting things in perspective …