Disease conditions of canine anal sacs

Ultrasound Morphology of Presumed Normal Anal Sacs in Dogs and Cats

Ultrasonographic evaluation of canine and feline anal sacs is a practical promising modality to identify anal sac disease. However, limited data are available about normal ultrasound morphology of the anal sacs. This study describes the ultrasound morphology of presumed normal anal sacs in a larger sample of client-owned dogs and cats. A single-institutional prospective cross-sectional descriptive study was performed, and 137 dogs and 131 cats were included. The most common ultrasound features of the evaluated anal sacs in the dorsal plane were oval shape (99.3% of dogs and 98.5% of cats) and bilaterally similar content (94.2% of dogs and 95.4% of cats), mostly hypoechoic with diffusely hyperechoic points or unformed echogenic material (42.6% of dogs and 44% of cats). Gas in the lumen of the anal sac was detected in two dogs and mineralization in one dog. There was a statistically significant positive correlation between body weight and the size of anal sacs in dogs ≤15 kg and cats and a correlation between age and the size of anal sacs in cats. This simple method provides additional clinically significant information in detecting abnormal findings in asymptomatic patients and could contribute to the early detection of anal sac disease.

Bacterial microbiota and proinflammatory cytokines in the anal sacs of treated and untreated atopic dogs: Comparison with a healthy control group

The pathogenesis of anal sacculitis has not been extensively investigated, although atopic dogs seem to be predisposed to the disease. The aim of this study was therefore to characterize and compare the bacterial microbiota and pro-inflammatory cytokines in the anal sacs of dogs from three groups (healthy dogs, untreated atopic dogs and atopic dogs receiving antipruritic treatment or allergen-specific immunotherapy) in order to determine whether changes could be at the origin of anal sacculitis in atopic dogs. Bacterial populations of anal sac secretions from fifteen healthy dogs, fourteen untreated and six treated atopic dogs were characterized by sequencing the V4 region of the 16S rRNA gene using Illumina technology. Proinflammatory cytokines were analyzed with the Luminex multiplex test. Community membership and structure were significantly different between the anal sacs of healthy and untreated atopic dogs (P = 0.002 and P = 0.003, respectively) and between those of untreated and treated atopic dogs (P = 0.012 and P = 0.017, respectively). However, the community structure was similar in healthy and treated atopic dogs (P = 0.332). Among the proinflammatory cytokines assessed, there was no significant difference between groups, except for interleukin 8 which was higher in the anal sacs of untreated atopic dogs compared to treated atopic dogs (P = 0.02), and tumor necrosis factor-alpha which was lower in the anal sacs of healthy dogs compared to treated atopic dogs (P = 0.04). These results reveal a dysbiosis in the anal sacs of atopic dogs, which may partially explain the predisposition of atopic dogs to develop bacterial anal sacculitis. Treatments received by atopic dogs (oclacitinib, desloratadine and allergen-specific immunotherapy) shift the microbiota of the anal sacs towards that of healthy dogs. Further studies are required to identify significant cytokines contributing to anal sacculitis in atopic dogs.

A retrospective study of treatment, outcome, recurrence and concurrent diseases in 190 dogs with anal sacculitis

BACKGROUND

Few studies report the treatment and recurrence rate in anal sacculitis (AS).

OBJECTIVES

Retrospective study reporting the management, recurrence and concurrent diseases in dogs with AS in a primary care practice.

ANIMALS

One hundred and ninety privately owned dogs in Sweden.

MATERIALS AND METHODS

Clinical records of dogs diagnosed with AS between 2018 and 2021 were reviewed, and management, time until clinical resolution, number of recurrent episodes and comorbidites were recorded.

RESULTS

The 190 dogs developed 290 episodes of AS. The most common management, in 235 of 290 (81.0%) episodes, was flushing ± infusion of an antimicrobial product into the sacs ± prescription of a nonsteroidal anti-inflammatory drug (NSAID), providing resolution in 213 of 235 (90.6%) episodes. Median time to resolution was one week (range 1-16 weeks), with resolution seen within one week in 205 of 290 (70.7%) episodes. A single episode of AS developed in 126 of 190 (66.3%) dogs. Dogs with concurrent cutaneous allergic disease were more likely (p < 0.001) to have recurrence of AS when compared to dogs with other comorbidities. Cutaneous allergic disease occurred more often (p < 0.001) in dogs with AS than in the practice population.

CONCLUSIONS AND CLINICAL RELEVANCE

Local treatment of the anal sacs ± systemic NSAID was the most common treatment, inducing clinical resolution in the majority of dogs. Cutaneous allergic disease was the most common concurrent diagnosis, with higher recurrence rate of AS compared to other diseases and occurring in higher prevalence than in the practice population. Further studies are needed to determine if management of cutaneous allergic disease would reduce the risk of AS.

Inside-out anal sacculectomy in small dog breeds and cats

This report describes a new, simple and rapid surgical technique for the removal of anal sac in small dogs and cats. The anal sacs were simply everted using mosquito hemostatic forceps and excised with the aid of an electrocautery surgical unit. On the evaluation of postoperative complications, only one dog of 28 animals experienced short-term minor complications of mild fecal incontinence and scooting. Thus, we suggest that this new surgical technique is easy, inexpensive and time-saving and some of the complications with previously reported methods used for small dog breeds and cats may be avoided by using this technique.

Local treatment for canine anal sacculitis: A retrospective study of 33 dogs

Background

Little information has been published regarding treatment of canine anal sacculitis (AS).

Objectives

Primary objective: determine the outcomes of AS local treatment at the referral dermatology service of the authors' institution. Secondary objective: determine signalment, body condition score (BCS), stool quality and comorbidities associated with AS.

Animals

Thirty‐three dogs with AS presented to the referral dermatology service between 1 January 2010 and 31 March 2021.

Materials and methods

An electronic medical record search was conducted. Information regarding sex, breed, age at disease onset, weight, BCS, stool quality, comorbidities, treatment and treatment outcome were collected. Treatment outcome was categorised as “resolved clinically”, “clinical signs resolved per owner”, “did not complete treatment” or “failed”. Dogs were excluded if seen by another service, not treated for AS, or if perianal sinuses (fistulae), anal sac masses, or anal sac abscesses were identified.

Results

Nineteen dogs were male and 14 female. Twenty‐four breeds were included. Average age at disease onset was 4.4 years. Average BCS was 5.8 of 9. Stool quality was “poor” in seven of 33 and normal in 23 of 33 cases. Atopic dermatitis was the most common comorbidity (12 of 33). Treatment typically consisted of anal sac flushing with saline followed by infusion using a commercially available steroid/antibiotic/antifungal ointment. Treatment was repeated on average 2.9 times. Resolution of AS was obtained in 24 of 33 cases, clinical signs resolved per owner in four of 33, five of 33 cases did not complete treatment, and no cases failed treatment.

Conclusions and clinical relevance

Local treatment with flushing and infusion is effective for treating AS in dogs.

Background – Little information has been published regarding treatment of canine anal sacculitis (AS).

Objectives – Primary objective: determine the outcomes of AS local treatment at the referral dermatology service of the authors' institution. Secondary objective: determine signalment, body condition score, stool quality and comorbidities associated with AS.

Conclusions and clinical relevance – Local treatment with flushing and infusion is effective for treating AS in dogs.

A Cross-Sectional Study on Canine and Feline Anal Sac Disease

Simple Summary

Anal sac disease is a common problem in private practice, but there is surprisingly little information available about anal sac disease in the literature. In this article, the incidence, predisposing factors, diagnostics, treatment options, and recurrence rates were investigated by the use of a questionnaire which was distributed among veterinarians in private practice. Dogs were more commonly affected than cats. Diarrhea and skin problems increased the risk for anal sac disease, and certain breeds were more often affected. Diagnosis was made based on the presence of clinical signs and characteristics of the anal sac content. Manual expression and treating any potential underlying disease were the most important treatments. Surgical removal was performed in the case of frequent recurrence. Surgical outcome of anal sacculectomy can be improved when surgery is performed after medical management. Future studies should investigate if these findings reported by veterinarians can be confirmed by asking veterinarians to keep a logbook on dogs and cats with anal sac disease.

Abstract

Limited data are available on canine and feline non-neoplastic anal sac disease. Therefore, the aim of this study was to obtain observational data on the incidence, predisposing factors, diagnosis, treatment, and recurrence rate of canine and feline anal sac disease. To this end, a questionnaire was distributed among veterinarians. The incidence of non-neoplastic anal sac disease was estimated at 15.7% in dogs and 0.4% in cats. Predisposing factors were diarrhea, skin problems, several dog breeds, and particularly small breed dogs, male cats, British shorthairs, and obesity in dogs. Diagnosis was made based on the presence of clinical signs and characteristics of the anal sac content. Manual expression and treating any potential underlying disease were the most important treatments for all three types of non-neoplastic anal sac disease. Anal sacculectomy was performed in refractory cases. The most recurrent anal sac disease condition was impaction. Diagnosis of anal sac disease should be based on clinical signs and rectal examination, as the evaluation of the anal sac content is not reliable. Surgical outcomes of anal sacculectomy can be improved when surgery is performed after medical management. Future studies should investigate these findings in prospective trials.

Outcomes and complications of anal sacculectomy for non-neoplastic anal sac disease in cats: 8 cases (2006-2019)

OBJECTIVES

To describe the features of non-neoplastic anal sac disease in cats, the surgical procedure, complications, surgical outcome and prognosis compared to well-established data for anal sacculectomy in canine patients.

MATERIALS AND METHODS

A retrospective review of medical records of cats undergoing anal sacculectomy for non-neoplastic disease between 2006 and 2019.

RESULTS

Eight cats were included in the study of which four of eight developed minor and self-limiting complications including defaecatory complications in three cases and superficial corneal ulceration in one case. No cat developed permanent faecal incontinence. No long-term postoperative complication was recorded. Median surgical time was 35 minutes (range, 20 to 42). Median hospitalisation time was 1.5 days (range, 1 to 4). The incidence of short-term minor complications is higher than previously reported in dogs, although this might be in agreement with a reported higher incidence in dogs smaller than 15 kg.

CLINICAL SIGNIFICANCE

Anal sacculectomy for non-neoplastic anal sac disease is a safe procedure in cats with relatively high rate of short-term but self-limiting, minor, postoperative complications.

Anal sacculiths may be an incidental finding in dogs

Mineral-attenuating material is occasionally seen in the anal sacs of dogs during abdominal CT studies. This retrospective, descriptive study was performed to estimate the prevalence and CT appearance of this mineral-attenuating material. A total of 357 abdominal CTs were reviewed retrospectively. The mineral-attenuating material was most easily identifiable using the brain window setting (window width: 120 HU; window level: 40 HU). In the current study, the prevalence of mineral-attenuating material in the anal sacs was 7.6% (95% confidence interval, 5.0-10.8%) with 48.1% bilateral involvement and equal distribution in the right and left in dogs with unilateral involvement. Successful collection and material analysis were performed in three dogs. The material was determined to be 100% dried blood, 100% waxy matter, and a "small amount of fat enmeshed in unidentified noncrystallined material." Given the CT appearance and the Hounsfield unit of these mineral-attenuating material within the anal sacs, the term "anal sacculiths" is proposed. All dogs with anal sacculiths within this study population did not have any reported disease of the anal sacs.

Staffordshire Bull Terriers in the UK: their disorder predispositions and protections

Background

The Staffordshire Bull Terrier is a popular dog breed in the UK but there is limited reliable evidence on disorder predispositions and protections within the breed. Using anonymised veterinary clinical data from the VetCompass™ Programme, this study aimed to identify common disorders with predisposition and protection in the Staffordshire Bull Terrier. The study hypothesised that Staffordshire Bull Terriers would have higher odds of aggression compared with non-Staffordshire Bull Terriers.

Results

The clinical records of a random sample of dogs of all types were reviewed to extract the most definitive diagnoses for all disorders existing during 2016. A combined list from the 30 most common disorders in Staffordshire Bull Terriers and the 30 most common disorders in non-Staffordshire Bull Terriers was generated. Multivariable logistic regression was used to report the odds of each of these disorders in 1304 (5.8%) Staffordshire Bull Terriers compared with 21,029 (94.2%) non-Staffordshire Bull Terriers. After accounting for confounding, Staffordshire Bull Terriers had significantly increased odds of 4/36 (11.1%) disorders compared to non-Staffordshire Bull Terriers with highest odds for seizure disorder (OR 2.06; 95% CI 1.24 to 3.40; p = 0.005). Conversely, Staffordshire Bull Terriers had reduced odds of 5/36 (13.9%) disorders, with lowest odds for patellar luxation (OR 0.15; 95% CI 0.04 to 0.61; p = 0.008). There was no significant difference in the odds of aggression between Staffordshire Bull Terriers compared with non-Staffordshire Bull Terriers (OR 1.09; 95% CI 0.75 to 1.58; p = 0.644).

Conclusions

This study provides a reliable evidence base of breed-specific disorder predispositions and protections that can be used by breeders to optimise breeding decisions. The findings can assist prospective owners of Staffordshire Bull Terriers to make informed decisions when acquiring a dog. From the relative number of predispositions to protections identified, there is no evidence that Staffordshire Bull Terriers have higher overall health problems than non-Staffordshire Bull Terriers.

Miniature Schnauzers under primary veterinary care in the UK in 2013: demography, mortality and disorders

BACKGROUND

Individual dog breeds are often reported as predisposed to specific breed-related disorders but reliable epidemiological data on disease prevalence are sparse. The Miniature Schnauzer in the UK is a popular small breed dog that is often considered as relatively healthy and long-lived, but is this really true? This study aimed to use data from the VetCompass™ Programme at the Royal Veterinary College to characterise the demography, mortality and common disorders of the general population of Miniature Schnauzers under veterinary care in the UK.

RESULTS

The study population of 455,557 dogs from 304 clinics in the VetCompass™ database under veterinary care during 2013 included 3857 Miniature Schnauzers (0.85%). For dogs with data available, 1771 (56.9%) were neutered and 1893 (49.2%) were females. Mean adult bodyweight overall was 9.9 kg (SD 2.2 kg) and median longevity was 11.6 years (IQR 9.3-13.1, range 0.5-17.0). The most prevalent fine-level precision disorders recorded were periodontal disease (n = 343, prevalence 17.4, 95% CI: 15.7-19.1), obesity/overweight (164, 8.3, 95% CI: 7.1-9.6), anal sac impaction (114, 5.8, 95% CI: 4.8-6.9), vomiting (100, 5.1, 95% CI% 4.1-6.1) and otitis externa (99, 5.0, 95% CI% 4.1-6.1). The most prevalent grouped-level precision disorders were dental (n = 378, prevalence: 19.2, 95% CI: 17.5-21.0), enteropathy (270, 13.7, 95% CI: 12.2-15.3), cutaneous (250, 12.7, 95% CI: 11.2-14.2) and aural (197, 10.0, 95% CI: 8.7-11.4).

CONCLUSIONS

This study provides generalisable evidence on the demography, longevity and most prevalent disorders in the Miniature Schnauzer breed in the UK. Awareness of common diseases and breed predispositions can support evidence-based policies to improve breed health, guide veterinary surgeons when producing differential diagnosis lists, and assist owners when purchasing or caring for their pets.

Diagnostic imaging features of normal anal sacs in dogs and cats

This study was conducted to provide normal reference features for canine and feline anal sacs using ultrasound, low-field magnetic resonance imaging (MRI) and radiograph contrast as diagnostic imaging tools. A total of ten clinically normal beagle dogs and eight clinically normally cats were included. General radiography with contrast, ultrasonography and low-field MRI scans were performed. The visualization of anal sacs, which are located at distinct sites in dogs and cats, is possible with a contrast study on radiography. Most surfaces of the anal sacs tissue, occasionally appearing as a hyperechoic thin line, were surrounded by the hypoechoic external sphincter muscle on ultrasonography. The normal anal sac contents of dogs and cats had variable echogenicity. Signals of anal sac contents on low-field MRI varied in cats and dogs, and contrast medium using T1-weighted images enhanced the anal sac walls more obviously than that on ultrasonography. In conclusion, this study provides the normal features of anal sacs from dogs and cats on diagnostic imaging. Further studies including anal sac evaluation are expected to investigate disease conditions.

Sexual dimorphism and condition dependence in the anal pad of the small Indian mongoose (Herpestes auropunctatus)

Secondary sexual traits tend to be sexually dimorphic, and theory predicts that such traits should also be condition-dependent in a sex-specific manner. We investigate these phenomena in a field study of the small Indian mongoose (Herpestes auropunctatus (Hodgson, 1836); formerly Herpestes javanicus (É. Geoffroy Saint-Hillaire, 1818)), in the first attempt at understanding secondary sexual traits and sexual selection in this species. Small Indian mongooses are solitary and nonterritorial, and they likely depend on chemical (scent) rather than visual or acoustic signals for communication. Additionally, they possess a fleshy projection around their anus, the anal pad, thought to aid in scent-marking. Our results revealed strong male-biased sexual dimorphism in mass, skull and body lengths, canine diameters, and anal pad area. After controlling for the influence of body length, males were 31% heavier and possessed anal pads that were 68% larger than females’. Additionally, anal pad size was positively related to body size in males but not in females and was condition-dependent in males but not in females. Taken together, our findings provide indirect evidence that the anal pad might have evolved, at least in part, via sexual selection.

NADPH-d-positive mast cells in the canine paranal sinus

This study aimed to investigate the enzyme histochemical expression of NADPH-d in mast cells in the wall of the paranal sinus in male and female dogs. NADPH-d-positive cells with weak, medium and strong enzyme histochemical expression were observed in the stroma of the sinus near the blood vessels of the microcirculatory bed and around the apocrine and sebaceous glands. In the same areas, mast cells with similar dimensions and morphology were demonstrated by metachromasia on paraffin and cryostat cross-sections and stained with 0.1% toluidine blue in McIlvane's buffer (pH 3). These findings suggest that the mast cells that are located in the stroma near the blood vessels, the lining epithelium and the glands correspond with the cells with marked NADPH-d activity. The possibility of mast cells having nitric oxide activity could be used in the regulation of mast cells function when treating paranal sinus tumours and inflammations.

Breed, gender and neutering status of British dogs with anal sac gland carcinoma

This study details the breed, gender and neutering status of a large cohort of British canine patients suffering from histologically confirmed anal sac gland carcinoma. Estimates of the relative risk for the development of this disease attributable to these factors are calculated. To reduce the impact of sampling errors, cases were selected from veterinary histopathology laboratories rather than referral hospital databases, and multiple estimates of the general British canine population were used. The weaknesses of the statistical assumptions made are discussed. There was no evidence to support a gender predisposition for the development of this condition. English cocker spaniels are significantly over-represented, with a mean relative risk estimate of 7.3. The mean relative risk estimate associated with being neutered was 1.4; the effect of neutering appeared to be more significant in male dogs compared with that in female dogs.

The role of surgery in the management of canine anal furunculosis. A review of the literature and a retrospective evaluation of treatment by surgical resection in 51 dogs

AIMS

To retrospectively evaluate the outcome of surgical management of anal furunculosis (AF) in 51 dogs. To compare the outcome of surgery with those of current medical protocols by way of a review of the literature.

METHODS

Dogs referred for treatment of AF (n=51) were treated by en bloc surgical resection of diseased tissue and primary wound closure. This technique was combined with bilateral anal sacculectomy in all cases in which the anal sacs had not been previously removed. Immunomodulatory therapies were not used, with the exception of post-operative metronidazole antibiosis for 7-10 days. Follow-up was performed by the author using a telephone questionnaire.

RESULTS

Forty-eight dogs were eligible for post-operative follow-up 1.5 to 36 (mean 17.4, median 18) months after surgery. Lesion recurrence, faecal incontinence and stricture formation occurred in 2%, 4% and 13% of dogs, respectively. The percentage of dogs considered by their owners to have an acceptable level of faecal continence and an improved quality of life was 94%.

CONCLUSIONS AND CLINICAL RELEVANCE

The aetiopathogenesis of canine AF remains unclear. Whilst recent advances in medical management by the use of various immunomodulatory medications (such as cyclosporine) hold promise, this approach has yet to be refined with respect to affordability, long-term efficacy and morbidity. With meticulous surgical dissection and reconstruction techniques (anoplasty), excellent success rates can be achieved following a single surgical procedure with minimal complications. Surgery remains a viable treatment option, alone or in combination with immunomodulatory medications, until a more thorough understanding of this debilitating disease is achieved.

Gross and Cytological Characteristics of Normal Canine Anal-Sac Secretions

A study was conducted to characterize the gross and cytological characteristics of secretions from normal canine anal sacs. Fifty dogs with no recent history of anal-sac disease were selected consecutively and their anal sacs manually expressed. Of the 47 dogs with known or estimated ages, 27 were < 1 year olds. However, these youngest dogs were not significantly different from the rest in cell counts, viscosity, or presence of dark or light solid portions of the secretions. For all dogs combined, the secretions typically contained 41 (median) corneocytes per 400x magnification microscopic field, lots of basophilic background debris, and a mixture of Gram-positive cocci (173 per field; median), Gram-positive rods (29 per field; median), and Gram-negative rods (two per field; median). Although median counts across 10 400x fields per sac indicated no leucocytes or yeasts, many of the normal dogs had an occasional 400x field with non-degenerate neutrophils and yeasts. Erythrocytes were not a feature of these anal-sac secretions, and mononuclear leucocytes were found only rarely. Extreme heterogeneity existed in gross colour, consistency and the amount of solid material. Thus, these latter parameters probably would not be valid indicators of anal-sac disease.