Introduction

Anal sac problems are rather common in domestic dogs and are not particularly difficult to diagnose. It is important for owners to take these problems seriously and to seek veterinary assessment and advice, because without treatment the problems can progressively worsen.

How Anal Sac Problems Are Diagnosed

A thorough history and physical examination are essential when anal sac problems are suspected. After taking a complete history, the attending veterinarian will evaluate the rectal area visually and digitally (by hand). The digital examination can be quite painful, depending upon the cause of the problem, and sedation or even general anesthesia may be required to complete the physical examination without causing significant discomfort to the patient. Normal anal sac secretions are clear to pale yellowish-to-grayish brown. Impacted anal sacs often are plugged with a thick, pasty brown material, and inflamed sacs can eontain a creamy yellow or thin greenish secretion. Abscessed anal sacs will discharge a reddish-brown material, typically accompanied by a fever and obvious swelling and redness around the anal area.

The results of blood work (a complete blood count and serum chemistry panel) and a urinalysis are typically normal in most cases of anal sac disorders, although there may be noticeable abnormalities on blood work if anal sac abscesses have ruptured and the infection has spread. The attending veterinarian may recommend thoracic and pelvic radiographs (x-rays), and possibly an abdominal ultrasound, to rule out neoplasia (cancer) that may have metastasized. The veterinarian will take samples of the anal sac contents during the digital examination and will examine these under a microscope to look at what types of cells are in the anal sac material. This is called “cytology.” It may or may not be appropriate to culture the contents taken from the anal sacs, because the culture results can be difficult to interpret due to the normal presence of a great number of bacteria (called “normal flora”)in that region. However, a diagnosis of bacterial infection becomes much more likely if a single bacterial species is cultured from the sample.

It may be appropriate to assess the levels of parathyroid hormone-related protein levels in the dog’s blood, because they can be elevated in dogs with certain types of anal sac tumors. Abnominal ultrasound may also be helpful to assess whether the lymph nodes have been affected by metastatic disease.

Special Notes

Most anal sac problems in our companion dogs are not especially serious. The diagnosis of anal sac disorders is not unusually difficult in most cases, since the area involved is so isolated and accessible.