I frequently evaluate dogs and cats that fail to respond appropriately to a steroid trial initiated in primary care practice. In many cases, a family veterinarian examines a pet, makes a presumptive diagnosis, and prescribes a corticosteroid, most often prednisone or prednisolone, without confirmatory diagnostic testing.
Sometimes the pet improves. That response may suggest the initial clinical suspicion was correct. In other cases, however, the pet fails to improve or continues to decline. When that happens, important questions arise. Did the veterinarian recommend definitive diagnostic testing? If so, why did the family decline it? If not, why did treatment proceed based on a presumptive diagnosis rather than diagnostic confirmation?
These questions do not assign blame. Instead, they reflect the realities of clinical veterinary medicine and highlight the importance of communication, shared decision-making, and informed consent.
Empirical Therapy Within the Spectrum of Veterinary Care
Empirical therapy plays a legitimate role in veterinary medicine. In fact, it often represents an essential component of spectrum-of-care or contextualized care. Financial limitations, patient stability, concurrent disease, or client circumstances may prevent immediate pursuit of definitive diagnostics. In those situations, empirical therapy allows veterinarians to relieve suffering, stabilize patients, and provide clinically meaningful care.
However, empirical therapy carries important limitations, especially when corticosteroids enter the treatment plan. Steroids can alter diagnostic accuracy and influence long-term outcomes. For that reason, veterinarians must pair empirical steroid therapy with clear, explicit informed consent.
Pet parents deserve to understand why a veterinarian recommends empirical therapy, what benefits it may provide, and what risks or downstream consequences may follow.
Why Pet Parents Seek a Veterinary Specialist
Pet parents who seek consultation with a board-certified veterinary specialist demonstrate a deep commitment to their pet’s health. They often invest significant time, effort, and financial resources to improve the likelihood of a positive outcome. I feel privileged to work with many such families every day.
During these consultations, I obtain a detailed medical history and perform a comprehensive physical examination. I then recommend diagnostic testing to establish a definitive diagnosis and outline treatment options that can improve quality of life. Some families pursue all recommendations. Others decline specific diagnostics or therapies due to financial or personal constraints.
When families defer diagnostic testing, empirical therapy may again become necessary. In those cases, veterinarians must clearly explain the limitations of that approach.
When Empirical Steroid Therapy Creates Challenges
Veterinarians rely on empirical therapy when clinical circumstances demand flexibility. Clinical experience and probability often guide these decisions. However, corticosteroids introduce unique challenges. Steroids may temporarily improve clinical signs while simultaneously obscuring the underlying disease.
The following example illustrates how this situation commonly unfolds.
A Common Clinical Scenario
Consider a geriatric Maltese with intermittent vomiting for one month. Concerned, you bring her to your primary care veterinarian for evaluation.
The First Round of Treatment
During the physical examination, the veterinarian notes weight loss compared with the previous visit six months earlier. Baseline bloodwork and abdominal radiographs appear normal. Suspecting dietary indiscretion, the veterinarian prescribes an antibiotic and an anti-vomiting medication. Despite consistent administration, vomiting persists. Appetite declines, and intermittent diarrhea develops.
The Second Round of Treatment
The veterinarian performs testing for pancreatitis, which returns normal. Based on concern for inflammatory bowel disease, the veterinarian prescribes a different antibiotic, a prescription diet, an appetite stimulant, and an alternative anti-nausea medication. After several weeks, the dog shows no meaningful improvement.
The Third Round: Steroids
Frustrated and worried, you return for reevaluation. The veterinarian continues to suspect inflammatory bowel disease and prescribes prednisone. Over the next two weeks, appetite and stool quality improve modestly. Vomiting and weight loss, however, persist. At this point, the veterinarian recommends referral to a board-certified internal medicine specialist.
The Specialist Consultation
During the consultation, the specialist performs a thorough evaluation and agrees that a primary gastrointestinal disorder likely explains the dog’s clinical signs. The leading differential diagnoses include inflammatory bowel disease and gastrointestinal lymphoma. The specialist explains that gastrointestinal biopsies provide the only way to definitively distinguish between these diseases.
You elect to pursue biopsies to determine whether your dog has inflammatory bowel disease or cancer. Unfortunately, prior steroid administration complicates that plan.
How Steroids Interfere With Diagnosis and Treatment
Steroids Alter Biopsy Results
Veterinarians commonly use corticosteroids to treat both inflammatory bowel disease and gastrointestinal lymphoma. Although steroids reduce inflammation, they also alter cellular morphology. As a result, pathologists may struggle or fail to confirm lymphoma after steroid exposure.
Steroids Impair Tissue Healing
Steroids interfere with collagen deposition and tissue growth factors, which impairs wound healing. Because of this effect, surgeons often hesitate to perform intestinal biopsies in patients currently receiving corticosteroids due to increased risk of surgical complications.
Steroids Can Worsen Lymphoma Outcomes
Prednisone administration before chemotherapy can induce drug resistance in lymphoma. Dogs that receive steroids prior to chemotherapy often experience shorter remission durations and poorer overall outcomes. Several studies associate worse prognosis with steroid administration lasting more than two weeks before chemotherapy initiation.
Why Informed Consent Matters With Empirical Steroid Therapy
When veterinarians recommend empirical therapy, especially when corticosteroids form part of the plan, pet parents must receive clear, transparent informed consent. These discussions should address:
- The potential benefits, including symptom control or short-term clinical improvement
- The limitations, such as masking or altering the underlying disease process
- The risks, including reduced diagnostic accuracy and restricted future treatment options
Informed consent ensures pet parents understand not only what a medication may accomplish today, but also what it may compromise tomorrow. This understanding supports ethical decision-making and strengthens the veterinarian-client-patient relationship.
The Take-Home Message About Steroids in Dogs
Veterinarians should always prioritize definitive diagnosis whenever possible. A confirmed diagnosis allows clinicians to select targeted therapies, optimize outcomes, and minimize unnecessary risk.
That said, empirical therapy remains an important and compassionate component of the spectrum of veterinary care. When veterinarians use empirical steroid therapy thoughtfully and pair it with thorough informed consent, they can provide ethical, patient-centered care while preserving trust and transparency.
Hi Dr Byers, I thought the recent studies showed that pre-treatment with prednisolone did NOT create a drug resistenc ein lymphoma? Maybe that is just cats? I’ll hunt around for the reference if you haven’t read that particular one. It makes sense that cancer cells can be selectively resistent in the same way as bacteria. However, while appreciating how difficult it is for the specialists, the primary care veterinarian is under somewhat different pressures – I would like to know how many ex-lap biopsies have to be done for pets-of-a-specified-group in order to find one or two cases where the differential mattered over a 12 – 18 month period. I don’t think anyone knows, which is why it is hard to sound convincing to an owner when recommending – essentially – major surgery on a .. gut .. feeling. Biology is tricky isn’t it?
Indeed biology can be truly tricky!
Pre-chemotherapy glucocorticoid exposure is thought to affect response duration with minimal-to-no effect on response rate. The story about pretreatment with corticosteroids having negative impact on median survival for canine multicentric lymphoma started more than 20 years ago (Price et al, J Vet Intern Med, 1991) and has been evaluated several times since in retrospective studies. There was a recent retrospective of feline gastric LSA (Gustafson et al, J Am Anim Hosp Assoc, 2013) that showed prior treatment with prednisolone was not a significant prognostic variable. But another study by Taylor et al (J Sm Anim Pract, 2009) retrospectively evaluated feline extra nodal lymphoma. For cats in this study who achieved complete remission, prior treatment with corticosteroids significantly reduced survival time.
Nevertheless this issue still hasn’t been rigorously studied in an organized, prospective fashion. We still don’t know the impact of different corticosteroids, different dosing regimens, different lengths of treatment before starting chemo, etc. Although the negative effects of pre-chemotherapy steroids may occur as soon as a few days after commencing use, clinically it seems like the window may be something closer to 2 weeks (at least in dogs). Until we have more data, I agree wholeheartedly with medical oncologists who state it is prudent to avoid corticosteroid pretreatment. Having said that, I recognize there are times when it is unavoidable. If you find yourself in that situation, try not to worry about it…too much! A major point is to avoid starting steroids before staging is complete.
To your second point as to whether the differential matters (and if I interpreted your point correctly), I wholeheartedly believe it matters. I can never stress enough the importance of basing treatment on a definitive diagnosis whenever possible. While it is true small cell/low-grade alimentary LSA may be treated quite similarly to lymphoplasmacytic enteritis/IBD (with prednisolone & chlorambucil), large cell/high-grade alimentary LSA should ideally be treated with a multi-agent chemotherapy protocol (i.e. CHOP, etc.). Alternatively if your IBD patient doesn’t positively respond to initial therapies, by having a definitive diagnosis you have the ability to safely reach for another appropriate & justifiable immunomodulatory agent rather than making a best guess. Finally survival times are quite different, and in my experience, parents prefer to know this information. A well-controlled IBD cat can lead a normal & happy lifestyle, and certainly the MST for small cell LSA is better than that for large cell LSA. In my experience, when I provide parents with this information, they elect to obtain a definitive diagnosis much more often than not.