Mycoplasma Pneumoniae and Hemolytic Anemia

Today we had the pleasure of a guest visit from Dr. Ho Ping-Kong, who walked us through a fascinating case of cold-agglutinin hemolytic anemia secondary to mycoplasma pneumoniae infection in a young man presenting with jaundice.

Mycoplasma pneumoniae is a common cause of community-acquired pneumonia in younger patients. It can cause both upper and lower respiratory tract infections. It typically has a prolonged and gradual onset, with prolonged paroxysmal cough. Its incubation period can be up to three weeks. Of note, although one of the most common causes of pneumonia in people younger than 40, only 10% of patients with mycoplasma pneumoniae infection will develop pneumonia.

Typically patients complain of fever, malaise, persistent dry cough, headache, chills, and coryza. Tracheal tenderness, chest soreness and pleuritic chest pain can occur, all because of the protracted cough. Patients typically do not appear unwell, and have nonspecific findings like pharyngeal injection and usually normal lung fields. Imaging can show bronchopneumonia, interstitial or reticulonodular infiltrates bilaterally (lower lobe predominance), and atelectasis.

Mycoplasma pneumoniae is associated with many extra-pulmonary manifestations, including acute hepatitis, ITP, cold-aggulitinin mediated autoimmune hemolytic anemia, arthritis, Stevens-Johnson syndrome, conduction abnormalities and transverse myelitis. These can occur before, during, after, or even in the absence of respiratory symptoms.

It is difficult to culture and, lacking a cell wall, cannot be seen on gram stain. Mycoplasma serology and PCR testing can be done. Cold agglutination testing is often positive, even in patients not actively hemolyzing. Often these cold agglutinants result in subclinical hemolysis and reticulocytosis.

In patients presenting with jaundice found to have hemolytic anemia, it is important to think of other potential causes of hemolysis - our patient had incidental G6PD deficiency! Similarly, mycoplasma pneumonia has been associated with chest crisis in sickle cell disease, making this an important entity to rule out as well.

Macrolides or doxycycline can be used against this atypical pneumonia. The complications of the pneumonia can be treated supportively. Patients who are hemolyzing should not be transfused if possible, as this can worsen the hemolysis. While admitted, patients should be under droplet precautions.

See here for a quick case report and review.