What is the underlying pathophysiology of EM’s condition?

Patient With Fatigue

EM is a 74-year-old male with a history of rheumatoid arthritis (RA) who presents in the clinic with a complaint of fatigue. EM is ambulatory with a walker and recently has had intermittent flare-ups of his rheumatoid arthritis (RA) disease activity, with increasing pain and swelling in his affected joints. His energy has been declining over the past few months, so he thought it was a good time to come in for follow-up laboratory testing and reassessment of his medications. Most troublesome, he has fainted twice in the past 2 weeks, which resulted in falls onto his carpeted floor. He is afraid to go out into public and even more afraid to drive his car. He has also had some chest pains with exertion. He is eating and sleeping okay, although he does sleep better if his head is elevated on a few extra pillows. He lives alone and gets meals delivered by a local organization.

Past Medical History

RA for 35 years, affecting hands, feet, knees, hips, and cervical spine
Systolic hypertension
Presbycusis

Medications

Ibuprofen, 600 mg three to four times per day as needed
Methotrexate, 7.5 mg weekly
Atenolol, 25 mg daily
Hydrocodone/acetaminophen, 5 mg/500 mg every 6 hours as needed for pain

Physical Examination

Height: 71 inches; weight: 160 lbs.; BMI: 22.3; blood pressure: 162/60; pulse: 84; respiration rate: 16; temperature: 98.6 °F
Well-developed, well-nourished elderly male in no distress; pale
Lungs: bibasilar rales
Heart: regular rate and rhythm, grade 3/6 systolic murmur, audible S3; positive carotid bruit on the left
Abdomen: no masses, nontender
Rectal: prostate 3+ enlarged, hemoccult negative brown stool
Extremities: marked ulnar deviation of MCP and IP joints in both hands