Clinical
From the guidelines: Chemotherapy nadir appointment considerations
A chemotherapy patient’s nadir appointment is the period after treatment when blood counts (especially white blood cells) hit their lowest point, which can have serious implications.
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The 2026 AAHA Oncology Guidelines for Dogs and Cats offer the latest recommendations on cancer diagnosis and treatment for the primary care veterinary team.
Section 5 of the guidelines deals with chemotherapy, a common cancer treatment that offers a variety of approaches tailored to small animal patients. Most veterinary chemotherapy protocols are well tolerated, with side effects that are typically mild and manageable, such as vomiting, diarrhea, and lethargy.
However, with certain drugs, chemotherapy can also lead to myelosuppression (bone marrow suppression) which can cause neutropenia. Neutropenia is a condition characterized by low levels of neutrophils, a type of white blood cell that fights bacterial infections, leaving the patient more vulnerable to infection. Febrile neutropenia is an oncologic emergency requiring hospitalization.
Neutrophil levels are typically lowest 7 days after the chemotherapy treatment (known as the nadir), but this will vary depending on the drug(s) administered and protocol. It is important to check the patient’s complete blood count (CBC) at the time of the anticipated nadir.
The guidelines state that at the nadir appointment, it is important to run a CBC, gather a thorough history, take vital signs (especially temperature, as identifying fever is crucial in neutropenic patients), and conduct a complete physical examination. The neutrophil count, not the total white blood cell count, is the primary indicator of concern. Table 5.4 below lays out the plan of care for when different levels of neutrophils are detected.
Understanding chemotherapy side effects, especially serious ones like neutropenia, is key to providing the best patient outcome possible.
TABLE 5.4 Nadir Appointment Action Plan
Neutrophil Count/microLiter |
Fever and Systemic Signs |
Plan |
|---|---|---|
1000 to 2000 |
No |
|
<1000 |
No |
|
<1500 |
Yes |
|
AAHA’s veterinary practice guidelines offer the latest clinical and nonclinical guidance on a wide range of topics. From the Guidelines presents bite-sized nuggets of wisdom from these guidelines for the practice team to consider.
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