Question

A university student presents to her primary care physician with fever, malaise, a sore throat, and a dry cough. The physician diagnoses her with flu symptoms and suggests bed rest, analgesics, and plenty of fluids. After 1 week, her symptoms worsened slightly with chest pain and earache. The patient’s primary care physician collects a sputum sample, after some effort on the patient’s part and obtains a blood sample. No bacteria are found in the sputum.  A chest radiograph shows small diffuse infiltrates that look worse than would have been expected. After receiving the result of the cold agglutinin titer from the laboratory, the physician is now pretty sure what is causing the problem.

1. What is causing the sickness in this student? What led you to this decision?

Answer 1

The sickness in this student is due to the infection caused by Mycoplasma pneumoniae.

Reason:

This pathogen primarily causes atypical pneumonia characterized by a sore throat, dry cough, chest pain, fever, and earache. Patients with Mycoplasma pneumoniae infection produce antibody against this pathogen. Interestingly these antibodies also react and agglutinate a suspension of human O group RBC when they were incubated at 4^oC. These are also called autoantibodies belonging to IgM class which specifically bind to the I antigen of human RBC. This is the principle of cold agglutination test.

In the given question, the physician was pretty much sure about the Mycoplasma pneumoniae infection as the student showed a positive result for the cold agglutinin test. Hence, this led to the decision that the sickness in this student is due to Mycoplasma pneumoniae infection.