Organ affected: kidneys

Lesson 2 Patient stories

Three patients describe kidney symptoms, diagnosis delays, treatment choices, and the relief that comes with the correct diagnosis, effective treatment, and careful follow-up.

Kidney involvement in IgG4-RD creates common but differing stories

Kidney involvement in IgG4-related disease (IgG4-RD) means the immune system causes inflammation in or around the kidneys, the ureters, or nearby tissue. The ureters are the small tubes that carry urine from the kidneys to the bladder. When inflammation or scar-like tissue blocks those tubes, urine can back up into the kidney and harm kidney function.

Kidney IgG4-RD does not always feel dramatic at first. In fact, when IgG4-RD affects the kidneys directly, most patients feel very normal for a long time. They may feel normal or almost normal while their kidney numbers – blood and urine tests – quietly demonstrate the slow progression of problems in kidney function. Others may fatigue or experience weight loss, but these symptoms are non-specific and don’t point clearly at the kidney as the source of the problem.

On the other hand, when the inflammation of IgG4-RD affects the ureters, blocking urine flow through these tubes and leading to the condition known as “hydronephrosis”, the presentation can be sudden and quite dramatic. The patient can be seized by pain in the right or left flank that is reminiscent of a kidney stone, leading very quickly to medical attention. But even hydronephrosis sometimes has a more subtle presentation that can take weeks, months, or even longer to become evident – all the while leading to kidney damage.

A common theme is that kidney IgG4-RD can look like other serious problems. Doctors may worry about cancer, multiple myeloma, kidney stones, or unexplained chronic kidney disease. That can lead to urgent imaging, biopsies, stents, specialist visits, and difficult treatment decisions before the full picture becomes clear.

In the stories below, you’ll hear how symptoms began, what made diagnosis difficult, and how treatment and careful follow-up helped patients move from fear and uncertainty toward a more stable life.

The kidneys are the body’s filter system. They clean the blood, help control blood pressure, balance fluids and electrolytes, and make urine. When IgG4-RD affects the kidneys or blocks urine flow, protecting kidney function becomes the main goal.

Patient stories

John Durcan: A “kidney stone” pain revealed retroperitoneal fibrosis

“It felt like someone had stabbed you in the left flank,” Said John

John Durcan’s story began suddenly, during an ordinary walk around Boston’s Jamaica Pond. He felt a sharp, stabbing pain in his left kidney area. Because the pain came on fast, caused nausea, and felt like classic kidney stone pain, that was his first thought. The pain slowly improved, and for a short time it seemed as if the problem might have passed.

The clue came later, at an annual visit. John’s blood pressure was higher than usual. When he mentioned the earlier “kidney stone” episode, his doctor added kidney function tests to the blood work. Those tests showed that his kidney function was down. Imaging then showed an abdominal mass near the aorta and hydronephrosis. The mass was leading to a blockage of urine flow to one of his kidneys, a condition known as hydronephrosis. Hydronephrosis is caused by a buildup of urine that cannot drain properly into the bladder. It is not a disease itself, but rather a sign of an underlying blockage in the urinary tract. If left untreated, this pressure causes swelling of one or both kidneys and can damage kidney function, sometimes permanently.

This sudden onset of flank pain was one of the classic presentations of retroperitoneal fibrosis, or RPF. Retroperitoneal fibrosis means inflamed, scar-like tissue forms deep in the abdomen, often around the aorta and the ureters. In IgG4-RD, that tissue can trap the ureters and block urine flow. Mr. Durcan needed a ureteral stent to relieve the blockage and protect the kidney. Prednisone did not shrink the mass enough, so treatment moved to B-cell depletion with rituximab. The mass improved, but scar tissue remained, and he ultimately underwent a surgical procedure called a “ureterolysis” to free the ureter from the fibrotic tissue.

Mr. Durcan’s story shows how kidney-threatening IgG4-RD can appear quickly, even when the actual inflammation may have been building quietly. It also shows why protecting urine flow is urgent. Sometimes the first step is not the final answer; it is the emergency step that keeps the kidney safe while the team works toward longer-term disease control.

“This presentation is classic,” said Dr. John Stone. “The retroperitoneal fibrosis with the appearance of the mass in this area really is a classic presentation.”

Michael Bamber: Kidney disease, weight loss, and the power of a caregiver’s voice

“All of a sudden, I lost 20 pounds,” said Michael.

Michael Bamber was diagnosed with IgG4-RD in 2015. Looking back, however, it is clear that his first symptoms had begun years earlier. In 2010, he had rapid, unexplained weight loss. He lost about 20 pounds over a short period. He and Linda spent the next year seeing many specialists and going through many tests, but no clear explanation emerged.

One important clue did appear: Michael had kidney disease. At first, no one connected the weight loss with the change in kidney function. An early kidney biopsy did not give an answer. For several years, things seemed fairly stable, and Michael focused on kidney-friendly eating and follow-up.

Then his kidney function began to decline again. His creatinine level kept rising, and Linda noticed that the scale kept moving in the wrong direction. When the response felt too slow, she pushed for earlier evaluation. Her words were plain and powerful: “There’s nothing wrong with our scales. And certainly something is very wrong with him.”

A second kidney biopsy and imaging review brought the diagnosis into focus. Doctors told Michael and Linda that the scans did not look like cancer, but did suggest IgG4-RD affecting the kidneys. Steroids helped save kidney function, but they brought side effects, including moon face, thinning skin, and concerns about blood sugar. Later, Michael went to the Massachusetts General Hospital (MGH), participated in a clinical trial, and then used B-cell depletion when disease activity returned.

Michael and Linda’s story shows that kidney IgG4-RD may be easy to miss when symptoms are general, like weight loss and fatigue. It also shows how important caregivers can be. Linda did not diagnose the disease, but she helped keep the urgency visible when the numbers and the lived experience did not feel reassuring.

“The technical terms for it is hypodense areas in the cortex of the kidney,” said Dr. Stone. “That can be the radiologic finding which is typical of interstitial nephritis, which is the most common manifestation of IgG4 disease in the kidney.”

Christopher Prah: Urination trouble, enlarged kidneys, and a fast-moving diagnosis

“I could not release urine,” said Christopher.

Christopher Prah first noticed that he could not urinate normally. He also lost about 15 pounds over two to three months and felt a deep lack of energy. He had no fever, but he described fatigue, low appetite, and a general sense that something was wrong.

Because he had experienced kidney stones years earlier, Christopher knew this felt different. It was not the same kind of pain. Instead, he felt the need to urinate but could not release. Imaging showed enlarged kidneys, and his kidney function was reduced. His doctors considered multiple myeloma, a cancer of the bone marrow that can cause kidney problems, because his blood protein levels were high. A bone marrow biopsy ruled that out.

The kidney biopsy shifted the thinking, and Dr. Stone later connected the high blood protein level to IgG4. Christopher’s kidney disease was moving quickly, so early treatment mattered. Prednisone helped quickly, especially with urination. He then entered a clinical trial of a B-cell-inhibiting medicine called XmAb 5871, now known as obexelimab, and did well during the trial. Later, received rituximab when lab markers suggested the disease was becoming active again, he received B cell depletion.

Christopher’s story shows that IgG4-RD can affect the kidneys and the genitourinary tract in ways that are easy to mistake for more common problems. It also shows how useful monitoring can be after treatment. For Christopher, rising IgG4 levels and falling complement levels helped signal when treatment might be needed again.

“If we can make the diagnosis early enough before there is major organ damage…we can get patients back to feeling normal,” said Dr. Stone. “But they have to be monitored carefully.”

Common themes among kidney patients

Many people with kidney involvement in IgG4-RD tell stories that echo one another. Some have sudden pain. Some have quiet blood test changes. Some lose weight or feel unusually tired. Some have trouble urinating. Some – nearly all, it seems – are told about frightening possibilities such as cancer before the diagnosis of IgG4-RD becomes clear.

A major theme is that kidney IgG4-RD can be either visible or hidden. Retroperitoneal fibrosis may cause dramatic pain when a ureter becomes blocked. Tubulointerstitial nephritis, a form of inflammation inside the kidney tissue, may be much quieter and show up first as a rising creatinine level on blood tests.

You’ll often hear people describe:

• A sudden “kidney stone” moment, with flank pain, nausea, or severe discomfort, especially when a ureter becomes blocked.

• A quiet kidney-function problem, where blood tests show rising creatinine or falling filtration before the person feels very sick.

• Weight loss, fatigue, and low appetite that are real and important, even when they do not point to one obvious organ at first.

• A mass or abnormal imaging finding that raises fear of cancer, especially when tissue builds up around the aorta, ureters, or kidneys.

• Biopsy uncertainty, because a small or early sample may not always capture the disease clearly.

• A need for several specialists, often including nephrology, urology, rheumatology, radiology, and pathology.

• Treatment tradeoffs, especially when prednisone works but causes side effects, or when B-cell-directed therapy helps control disease but raises infection-related concerns.

• Caregiver advocacy, because family members may notice changes in weight, energy, mood, or daily function before those changes look dramatic on paper.

• Long-term monitoring, because kidney IgG4-RD may improve with treatment and later become active again.

In these kidney stories, the turning point is often the same: someone recognizes that the symptoms, imaging, blood tests, biopsy results, and patient story all belong together. Once that happens, the care plan can shift from chasing separate clues to protecting kidney function with purpose.

Why diagnosis can be challenging

Kidney IgG4-RD is challenging because it often looks like other conditions. A ureter blockage can look like a kidney stone. A mass near the aorta can raise concern for cancer. Kidney injury with high blood protein can raise concern for multiple myeloma. A mildly elevated IgG4 level may not seem dramatic enough to explain the problem. In some patients, the IgG4 blood level is not very high at all.

A biopsy can be very helpful, but it is not always simple. A small needle biopsy may show that cancer is unlikely, but it may not always provide enough tissue to fully prove IgG4-RD. In kidney disease, a biopsy can also miss the affected area if the inflammation is patchy. That is why diagnosis often depends on putting many clues together: symptoms, kidney function, urine flow, imaging patterns, blood tests, biopsy results, and expert review.

This can be frustrating for patients. It may feel as if each test answers only part of the question. But that careful approach matters, because the treatment plan for IgG4-RD is different from the plan for cancer, kidney stones, infection, or other causes of kidney disease.