Man’s case shows bacterial lung infection can ‘provoke’ clots, CAD
Report highlights potential dangers of M. pneumoniae bacterium
A bacterial lung infection caused by Mycoplasma pneumoniae— a very small cell bacterium known as M. pneumoniae for short — triggered cold agglutinin disease (CAD) and severe blood clotting in a man in his late 50s, according to a case report from the U.S.
The man recovered after treatment with plasmapheresis, a blood-cleaning procedure that can remove harmful self-reactive antibodies from the blood, and anticoagulants, or blood thinners.
But a trio of researchers noted that his case highlights the uncommon, but severe issues that can arise in people who develop respiratory tract infections due to M. pneumoniae.
“Although Mycoplasma pneumoniae commonly presents as a self-limited respiratory illness, it can infrequently provoke severe … complications” outside the lungs — such as the blood clots seen in this patient — the team wrote.
Their report, “Fulminant Thromboembolism and Cold Agglutinin Hemolysis Secondary to Mycoplasma pneumoniae Infection,” was published in the journal Archivos de Bronconeumología.
An autoimmune disorder, CAD is caused by the immune system’s wrongful production of self-targeting antibodies, called cold agglutinins, that bind to red blood cells at low temperatures. This attachment causes the cells to clump together and be marked for destruction, a process known as hemolysis.
It can lead to the formation of blood clots that block vessels, and also reduce the number of circulating red blood cells, leading to anemia, impaired oxygen delivery throughout the body, fatigue, and other CAD symptoms.
CAD can occur on its own or be triggered by infections, cancer
The autoimmune disease, which is rare, may arise on its own or as secondary to other conditions, most commonly blood cancers or infections, such as those caused by the M. pneumoniae bacterium.
While this bacterium is best known for causing mild respiratory infections, it can sometimes lead to severe complications outside the lungs, including widespread blood vessel blockages.
Now, a team of researchers at The University of Toledo in Ohio described the case of a 59-year-old man who developed CAD and extensive blood clot-related problems secondary to an M. pneumoniae lung infection.
The man had recently returned from Europe when he developed a cough and pain in his right leg. He sought treatment at the hospital with shortness of breath, elevated heart rate, and low oxygen levels. A scan revealed multiple blood clots blocking blood vessels in both lungs, a condition known as pulmonary embolism, along with signs of heart strain.
He underwent an emergency thrombolysis — in which medications are administered promptly to help dissolve blood clots — as well as surgery to remove the clots and restore blood flow.
The man was treated with broad-spectrum antibiotics and blood thinners, and a subsequent test confirmed the airway infection was caused by M. pneumoniae, prompting a change in antibiotics.
Man made full recovery after treatment with plasma exchange
Still, the man’s condition worsened: He developed additional clots in both legs, low counts of blood clot-inducing platelets, and hemolytic anemia, in which the red blood cells are destroyed faster than they can be made. Overall, these signs and symptoms suggested CAD.
The man also showed signs of disseminated intravascular coagulation, a life-threatening condition in which the body’s clotting system becomes overactive, leading to many tiny clots in blood vessels all over the body.
Further tests confirmed red blood cell clumping and high levels of cold agglutinins — hallmarks of CAD. With other causes ruled out, the clinicians determined that M. pneumoniae had triggered CAD in this case.
This case underscores the potential of M. pneumoniae to act as a [body-wide] pathogen capable of triggering [several blood clot-related problems].
The man was started on plasmapheresis, or plasma exchange, to remove cold agglutinins from the bloodstream, along with blood transfusions and blood thinners. He responded well to treatment, with resolution of hemolysis, improved oxygen levels, and normalization of his blood clotting parameters, according to the team. His lung function recovered completely, the researchers reported.
According to the team, “this case underscores the potential of M. pneumoniae to act as a [body-wide] pathogen capable of triggering [several blood clot-related problems].”
The researchers concluded: “Our case contributes to growing awareness of this unusual but serious complication of a common respiratory pathogen and emphasizes the value of a high index of suspicion and interdisciplinary management.”
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