Probing for inflammation
James Katz was the Senior Research Fellow at the National Institute of Arthritis and Musculoskeletal and Skin Diseases at the National Institutes of Health in Bethesda, Maryland. After hearing the patient’s story, he left the exam room to allow her to change into a hospital gown. While he waited, Katz considered the possibilities. When he first heard that she had joint pain that was resolved with prednisone, the specialist thought she likely had rheumatoid arthritis (RA). It was one of the most common inflammatory joint diseases in women her age and could sometimes affect the lungs. But she took extremely high doses of prednisone to manage her symptoms, and that wasn’t usually necessary to treat RA, which is usually extremely sensitive to the anti-inflammatory properties of steroids. Most patients with RA could be treated with five to 10 milligrams of prednisone. She needed 10 times that. No, decided Katz, that was probably something else.
At the top of his new list was a rare disease formerly known as Churg-Strauss syndrome, now known as eosinophilic granulomatosis with polyangiitis (EGPA). This is a disease not of the joints – like RA – but of the blood vessels. Vasculitis like EGPA is dangerous because the blood vessels affected can be anywhere in the body. EGPA often starts in the lungs, often in those with asthma, but can then spread throughout the body. But with EGPA, patients have high levels of eosinophils, the white blood cells that drive the disease. Yours were normal. And EGPA usually causes more muscle pain than joint pain. So it didn’t fit that well.
When the doctor examined the young woman, he paid special attention to her joints. If she had any signs of inflammation there – redness or swelling or fluid in the joint space – it would make the diagnosis of EGPA even less likely. Her knees looked normal – not red, not swollen – but they were quite tender. He let her straighten her legs and then pressed gently but firmly on her right thigh, a few inches above the knee, and moved his hand down the leg until he reached the kneecap. The joint space of the knee extends into the thigh and so a small amount of fluid may be missed unless it is collected at the joint. He found no obvious liquid.
Then he gently pressed the outside of the knee joint. If there was fluid there, the only remaining area would be a small swelling on the other side of the knee called a bulge mark. Sure enough, there it was. Interesting. There was inflammation somewhere in the joint. If it was on the outer smooth surface where the joint came together, known as the synovium, then it was likely RA. But what if it was in the cartilage that cushioned the joint? Then he put pressure on a place on her chest where cartilage connects the ribs to the sternum. The patient jumped back in pain. “I didn’t even know it hurt there,” she exclaimed.
For Katz, these two results pointed to a very rare disease, a disease that causes inflammation and eventually destruction of the cartilage. “Do you sometimes have an earache when you wear a hat,” he asked, “or when you sleep on your side?” The patient was amazed. No one had ever asked this question. Yes, she replied. And did her nose ever get sore or red while wearing sunglasses? Again she was amazed. Yes sir. Frequently. What on earth could that mean? She was a doctor, an intensive care medicine specialist, and an infectious disease specialist, and she had never heard of any of these symptoms.