Mycoplasma pneumoniae Infection as a Treatable Cause of Brainstem Encephalitis

We read the recent article by Cree et al¹ with great interest. The authors present a case of a 33-year-old woman previously treated with immunosuppressive agents for Henoch-Schönlein purpura. Progressive development of initially flulike symptoms to severe neurological impairment with lethargy, cogwheeling, increased limb tone, and brisk reflexes was diagnosed as coxsackievirus B4 meningoencephalitis. Experimental therapy with the antiviral agent pleconaril was ineffective. Magnetic resonance imaging showed focal hyperintense lesions in the brainstem that correlated with pathologic findings seen at autopsy after fatal central nervous system infection and myocarditis.

One might suspect that coxsackie-virus B4 detection was associated with rather than causative of meningoencephalitis in this patient, so our recommendation is to extend the spectrum of differential diagnoses according to our experience in a case with a similar history as well as clinical and magnetic resonance imaging findings. A 20-year-old man was admitted to our hospital with a 2-week history of flulike symptoms followed by subacute development of neurological deficits including meningism, lethargy, proximal tetraparesis with brisk reflexes and equivocal plantar responses, and urinary bladder dysfunction. Examination of the cerebrospinal fluid revealed polymorphonuclear pleocytosis and serologic proof of Mycoplasma pneumoniae infection. Magnetic resonance imaging showed subtle, linear hyperintense lesions on T2-weighted images similar to the findings of Cree and colleagues (Figure 1). After modification of the initial empirical antibiotic therapy with doxycycline hyclate, the clinical course was favorable. After 4 weeks, the patient was discharged with only slight neuropsychologic deficits and no lesions henceforth in his magnetic resonance imaging results.

Both case histories show characteristics of acute brainstem encephalitis. Myocarditis was present in the case of Cree and colleagues, whereas our patient was diagnosed as having pneumonia. Although the combination of brainstem encephalitis and myocarditis is well recognized in M pneumoniae infection, testing for this atypical germ was not reported in the published case. Because treatment of this bacterial infection can result in a good prognosis, as demonstrated in our patient, we wonder whether therapy with tetracyclines or macrolides might have been beneficial in the patient described by Cree and colleagues had they tested for M pneumoniae.