Boy treated for rare case of CAD linked to lung infection, blood clot
Treatment included antibiotics, steroids, IV immunoglobulin, blood thinners
A boy in China was diagnosed with a rare case of cold agglutinin disease (CAD) associated with a Mycoplasma pneumoniae lung infection and a pulmonary embolism, which is a blood clot in the arteries that supply the lungs, according to a new case report.
After treatment with antibiotics, immune-suppressing steroids, intravenous immunoglobulin, and blood thinners, he was discharged from the hospital without signs of CAD, infection, or embolisms.
These findings “aimed to strengthen the understanding and therapy of Mycoplasma pneumoniae (MP) pneumonia combined with cold agglutinin disease and pulmonary embolism in children,” researchers wrote.
The study, “Severe mycoplasma pneumoniae pneumonia combined with cold agglutinin disease and pulmonary embolism in childhood: A case report and review of the literature,” was published in the African Journal of Reproductive Health.
In CAD, self-reactive antibodies called cold agglutinins bind to red blood cells at cold temperatures, causing them to clump together and marking them for destruction (hemolysis). This leads to anemia, which occurs when the body doesn’t produce enough healthy red blood cells and hemoglobin, the protein that transports oxygen throughout the body.
Symptoms can include fatigue, pain, bluish discoloration of skin
Due to a lack of oxygen associated with anemia, patients develop symptoms such as fatigue, pain, and a bluish discoloration of the skin called acrocyanosis.
CAD is classified as primary when its cause is unknown, or secondary when it’s associated with another illness such as an infection, cancer, or another autoimmune disease.
In children, CAD is almost always secondary to an infection, most commonly Mycoplasma pneumoniae, a bacterium involved in respiratory infections, and the Epstein-Barr virus, which causes infectious mononucleosis, also known as “mono.”
In this report, investigators in China describe the case of a 7-year-old boy with secondary CAD combined with Mycoplasma pneumoniae and a pulmonary embolism.
The boy was taken to the hospital due to a fever that had lasted for seven days, a cough for five days, and recurrent acrocyanosis in the extremities for one day. Suspecting an infection, the doctors treated him with antibiotics for three days but the boy failed to improve. Although warming relieved the acrocyanosis, it reoccurred. As a result, he was referred for hospital admission.
When the boy’s blood was collected on the day of admission, the team noted a blood clot on the wall of the tube. Routine blood tests revealed elevated white blood cell counts and C-reactive protein (CRP), a sign of inflammation, and lower-than-normal red blood cell counts and hemoglobin levels. He also tested positive for antibodies against Mycoplasma pneumoniae.
On the second day of hospitalization, he had blood in his sputum, right chest pain, shortness of breath, and an elevated breathing rate. CT scans of the lungs showed signs of a pulmonary embolism, double pneumonia, and right-sided pleural effusion, or an unusual amount of fluid around the right lung. Blood tests continued to show low red blood cell counts and hemoglobin levels.
Direct Coombs test indicates cold agglutinin antibodies
When the blood clot found on the tube was heated to body temperature, it disappeared. A direct Coombs test was positive, indicating cold agglutinin antibodies in the blood. The boy’s reticulocytes, or immature red blood cells, were elevated, a sign of anemia. Moreover, he tested positive for C3d, an immune system molecule known to play a role in CAD autoimmune attacks.
Based on all of the clinical findings, the boy was diagnosed with severe Mycoplasma pneumoniae infection with CAD and a pulmonary embolism.
He was treated with antibiotics to control the infection, immunosuppressing steroids to dampen inflammation, and intravenous immunoglobulin to alleviate hemolysis. He also received anticoagulants (heparin and warfarin), or blood thinners, to prevent blood clots.
On the fourth day of hospitalization, his body temperature normalized, and his cough, chest pain, and shortness of breath gradually eased. On the seventh day, blood test results showed improvement, including white and red cell counts, hemoglobin levels, reticulocytes, and CRP.
The boy was hospitalized for 13 days with normal body temperature and stable breathing but with occasional cough. More blood tests continued to show improvement.
The boy was then discharged and continued to take oral steroids (prednisone) and warfarin. One month later, a Coombs test was negative, and a chest CT scan at three months showed no signs of a pulmonary embolism.
“When patients with [Mycoplasma pneumoniae] pneumonia have acrocyanosis, red blood cell agglutination, and disproportionate changes in the relationship between hemoglobin decline and red blood cells, … secondary cold agglutinin disease should be vigilant, and the primary disease should be actively treated to avoid further progression of the disease,” the researchers concluded, adding that “although the disease may be associated with severe complications such as embolism, acrocyanosis, and gangrene, the prognosis is relatively good for most patients.”
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