Unusual colon lesions lead to PNH diagnosis in woman: Case report

Considering underlying conditions during diagnosis is key, researchers say

Margarida Maia, PhD avatar

by Margarida Maia, PhD |

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An illustration of the digestive system is shown, with lesions in the abdomen highlighted.

Unusual colon lesions caused by ischemic colitis led to the diagnosis of paroxysmal nocturnal hemoglobinuria (PNH) in an 82-year-old woman in Japan, but appropriate treatment eased her symptoms.

According to the authors, her case highlights the importance of considering underlying diseases when unusual features are observed in a person with ischemic colitis, an inflammation due to reduced blood flow in the colon, which is a portion of the large bowel.

“When a patient with ischemic colitis presents atypical lower gastrointestinal endoscopic findings, it is important to explore the presence of an underlying disease,” the researchers wrote.

Her case was described in the study, “Ravulizumab can effectively treat ischemic enteritis caused by paroxysmal nocturnal hemoglobinuria,” published in the Journal of Nippon Medical School.

PNH is characterized by the premature breakdown of blood cells. The disease has a wide array of symptoms, ranging from abdominal pain and fatigue to blood clots and dark urine. Many of these symptoms overlap with those of other conditions, sometimes making PNH difficult to diagnose.

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Underlying condition can lead to complications

In this study, researchers described the case of an 82-year-old woman who initially presented with ischemic colitis, a common condition with an usually favorable prognosis. However, complications can arise, especially when there is an underlying disease.

The woman visited the hospital’s outpatient department due to abdominal pain during the night. She had a history of chronic heart and kidney disease, breast cancer, heart attack, and hemorrhoidal fistula.

A CT scan revealed that a large part of the colon was inflamed, which made doctors suspect ischemic colitis or a bacterial infection. She was prescribed bowel rest and the antibiotic levofloxacin.

Two nights later, her abdominal pain worsened.

Blood testing revealed low hemoglobin — the protein that carries oxygen in red blood cells. Lactate dehydrogenase was higher than normal, indicating damage to cells in the body, as was the number of reticulocytes (immature red blood cells).

She was diagnosed with hemorrhagic anemia caused by ischemic colitis. Hemorrhagic anemia occurs when there are not enough red blood cells to meet the body’s demands because they break down or die faster than the body can replace them.

“After admission, the patient fasted and received supplemental fluids [to stay hydrated], and her abdominal pain gradually decreased,” the researchers wrote.

An endoscopy, a procedure in which doctors use a long, thin tube with a small camera to examine the inside of the digestive tract, revealed ulcerative lesions in the ascending, transverse, and descending colon.

A tissue biopsy obtained during the endoscopy revealed the presence of multiple fibrin thrombus formations in small blood vessels within the colon. Fibrin thrombi are blood clots made up of fibrin, a protein involved in blood clotting. This made doctors suspect an underlying blood disorder.

Flow cytometry, a lab technique used to examine the characteristics and count different types of cells, revealed that a large proportion of the patient’s blood cells lacked CD55 and CD59 proteins on their surface. Lack or low levels of these two proteins is considered a hallmark of PNH.

Based on these findings, doctors made a diagnosis of PNH and the woman was discharged from the hospital 21 days after being admitted. Two days later, she experienced bloody stools and abdominal pain, “which resolved spontaneously.”

However, she was considered severely ill due to abdominal pain and the need for monthly red blood cell transfusions. Therefore, she was started on Ultomiris (ravulizumab) after receiving meningococcal vaccination to protect against meningitis, a potential side effect of the medication.

After treatment with Ultomiris, ischemic colitis did not return, and red blood cell transfusions were reduced from four to six units each month to about two every one to two months.

“If a patient with ischemic colitis presents atypical lower gastrointestinal endoscopic findings, it is important to explore the presence of an underlying disease,” the researchers wrote.