This is necessarily conjecture at this time but you appear to be describing sundowners syndrome - a form of cognitive dysfunction in dogs and humans. It's conjectured that the dark and quiet of night magnifies the sensory loss in these patients which results in their anxiety and subsequent aberrant behavior
. Other indications of cognitive dysfunction include disorientation, changes in social and interactive behavior - becoming "needier" or, conversely, more aloof - changes in locomotor and sleep cycle behaviors, and loss of "housetraining".This is a progressive disorder, however, and so if Auden normalized for many weeks, cognitive dysfunction isn't likely and, instead, a medical disorder such as episodic gastroesophageal reflux (GERD, acid reflux, heartburn) might be considered. In that case, an over the counter antacid such as famotidine
(Pepcid) dosed at 0.25 mg/lb prior to bedtime might be administered as a test for heartburn. In cases of cognitive dysfunction, ancillary care involves physically and mentally stimulating exercises such as swimming, massage, and range of motion exercises, encouraging relaxation, ensuring that Auden is taken out frequently to minimize the cost of elimination "mistakes", encouraging reestablishment of daily cycles by feeding
at regular hours and at least a few hours before bedtime, and perhaps administering an anxyiolic (anti-anxiety) benzodiazepine such as diazepam or alprazolam (if available where you live) before bed. Specialized diets rich in antioxidants may be of value such as Hill's Prescription Diet b/d. The monoamine oxidase inhibitor selegiline (Anipryl) is the only drug licensed for use for the treatment of canine cognitive dysfunction in the States. Many of us aren't impressed with the studies supporting its use, however.Cognitive dysfunction in dogs is just as difficult to manage as is Altzheimer's in humans. Please respond with further questions or concerns if you wish.