Top 5 Clinical Signs of Stress in Dogs & Cats During Examination

A stress response activates the hypothalamic–pituitary–adrenal axis and autonomic nervous system (Figure 1), allowing the ability to cope with perceived or actual threats to homeostasis or well-being. Patient response to environmental stressors (eg, riding in a car, being in a carrier, other patients in the clinic, separation from the owner, examination in the clinic) can lead to changes in physical examination results and diagnostic findings. Recognizing the stress response is key for accurate interpretation of examination findings and diagnostic results and alleviation of patient stress during future examinations.

Following are the most common clinical signs of patient stress during examination and diagnostic testing, according to the author.

Dogs and cats use body language to express fear, anxiety, and stress. These signals can be subtle and easily missed; therefore, veterinary staff should be trained to observe and interpret clinical signs associated with stress (see Signs of Stress in the Body Language of Dogs & Cats).

The primary coping strategies of stressed patients include freezing, fleeing, fidgeting, or fighting, depending on patient proximity to the stressor, ability to escape, previous success of coping strategies, personality and genetics, and the speed at which the stressor moves toward the patient.^5,6 

Freezing is a passive coping strategy in which a dog or cat becomes as small, still, and quiet as possible to avoid a stressor.⁵ Freezing is often not recognized as a sign of stress because a frozen patient can appear cooperative and allow examination and diagnostic testing. Although these patients may appear normal, they are in emotional distress.

Patients may attempt to flee despite the limited size of typical examination rooms.⁵ This strategy may also be impossible when a patient is on a leash or in a carrier. 

Fidgeting is a means of displacing stress.⁵ Dogs may scratch their ears, rapidly blink their eyes, sniff excessively, lick their paws or genitals, lick their lips and yawn, or pant excessively. Cats may groom themselves excessively, scratch their ears, pant, or search for alternative hiding places. 

Fighting is often a last resort when other strategies to eliminate the stressor have been ineffective or the stressor is overwhelming and is an attempt at self-protection by moving the stressor away.⁵ Dogs may growl, snarl, lunge, bark, snap at the air, and/or bite. Cats may hiss, swat, growl, and/or bite. These aggressive behaviors can be a risk for veterinary staff and owners; therefore, minimizing patient stress is also important for human safety.

Vital signs (ie, heart rate, respiratory rate, temperature, blood pressure) can be altered by even low levels of stress (eg, during measurement of vital signs), making interpretation of test results difficult. Psychological stress activates the hypothalamic–pituitary–adrenal axis and engages the autonomic nervous system, resulting in a cascade of neurohormonal changes that can lead to tachycardia, tachypnea, hyperthermia, and hypertension.^7,8 A study comparing healthy dogs at home with those at the clinic demonstrated that pulse rate increased by 11%, panting significantly increased, rectal temperature slightly increased (<1%), and mean blood pressure increased by 16% in dogs at the clinic.⁹

Stress-induced activation of the hypothalamic–pituitary–adrenal axis results in elevated cortisol levels, leading to alterations in the CBC and serum chemistry profile. Hallmarks of a stress leukogram include neutrophilia, lymphopenia, monocytosis, and eosinopenia.¹⁰ Neutrophilia in dogs is ≈1 times the upper reference interval; however, in cats, neutrophilia can be ≤2 to 3 times the upper reference interval.¹⁰ Endogenous glucocorticoids induce gluconeogenesis, and high levels of epinephrine stimulate glycogenolysis, both of which can lead to hyperglycemia.¹⁰ High levels of circulating cortisol during hypothalamic–pituitary–adrenal axis activation can cause hypercortisolemia and hypercortisoluria that can be misclassified as possible hyperadrenocorticism.  

Recovery following acute psychological stress is important for mental well-being but can be impaired in patients with poor resilience or intense or prolonged psychological stress. Long-term stress can result in physical and/or emotional welfare challenges, including greater susceptibility to infection, delayed wound healing, sensitivity to pain, decreased postvaccination antibody response, and decreased life span.^11-16 Patients can also develop intense fears and phobias of the carrier, car ride, clinic, clinician, and/or handling procedures after just one stressful visit. 

Patients that return home and experience poor recovery from stress can develop chronic fear, anxiety, and stress that can lead to fear of or aggression toward the owner or other animals in the household, as well as increased stress at future visits to the clinic.

Mitigating fear, anxiety, and stress in patients is key to caring for emotional health. Patient stress should also be minimized for physical health, which can be affected by physiologic consequences of stress. Interpreting body language, identifying behavioral responses, and recognizing stress-associated changes in vital signs and diagnostic tests can help identify when intervention is needed.