Seek urgent veterinary care if your Brittany collapses, faints, has marked difficulty breathing, shows sudden severe weakness, has a painful or swollen limb, cannot stand, or develops a sudden major change in awareness or behavior. These signs may reflect a serious heart, orthopedic, neurologic, or other medical problem and should not be monitored at home.
For milder but persistent changes—such as recurring limping, stiffness after rest, reluctance to jump, lower exercise tolerance, coughing, or a change in appetite or energy—book a veterinary appointment promptly. Your veterinarian can examine your dog, review its history, and decide whether imaging, heart evaluation, or other testing is appropriate.
Until you have advice, keep activity calm, prevent jumping or rough play if your Brittany appears painful, and do not give over-the-counter human medication. Note when the signs began, what makes them better or worse, and any family-health information you have.