Mycoplasmas: their role in pediatric disease

Pediatric encephalitis: what is the role of Mycoplasma pneumoniae?

BACKGROUND

Encephalitis is a complex, debilitating, and sometimes fatal neurologic condition to which children are especially prone. Mycoplasma pneumoniae, a common respiratory pathogen, has been implicated as an etiology of encephalitis. Evidence for recent or acute M. pneumoniae infection has been demonstrated in limited studies of both pediatric and adult patients with encephalitis.

PATIENTS AND METHODS

Unexplained encephalitis cases are referred to the California Encephalitis Project for diagnostic testing. Serum, cerebrospinal fluid, and respiratory specimens are tested by polymerase chain reaction and serology methods for the presence of multiple pathogens, including M. pneumoniae. M. pneumonia-associated cases of encephalitis were compared with other bacterial agents, herpes simplex virus 1, and enterovirus.

RESULTS

Of 1988 patients referred to the California Encephalitis Project, evidence of acute M. pneumoniae infection was found in 111 patients, of which 84 (76%) were pediatric patients. Eighty percent of the 84 patients were positive for M. pneumoniae by serology alone. Cerebrospinal fluid polymerase chain reaction for M. pneumoniae was rarely positive (2%). Patients with M. pneumoniae-associated pediatric encephalitis were a median of 11 years old, progressed rapidly (median: 2 days from onset to hospitalization), and were often in the ICU (55%). Symptoms included fever (70%), lethargy (68%), and altered consciousness (58%). Gastrointestinal (45%) and respiratory (44%) symptoms were less common. Compared with patients with other bacterial as well as viral agents, patients with M. pneumoniae-associated encephalitis had fewer seizures and less-severe hospital courses.

CONCLUSIONS

M. pneumoniae is the most common agent implicated in the California Encephalitis Project. Patients with M. pneumoniae-associated encephalitis are predominantly pediatric, and their presentations are clinically similar to enterovirus encephalitis, although they frequently require intensive care with prolonged hospitalizations. Given that M. pneumoniae infection is found more than any other pathogen, increased emphasis should be placed on elucidating the role and mechanism of M. pneumoniae in encephalitis.

Mycoplasma pneumoniae infection is associated with Stevens-Johnson syndrome, not erythema multiforme (von Hebra)

A review of the English-language medical literature revealed at least 70 cases of well-documented Mycoplasma pneumoniae infections associated with the Stevens-Johnson syndrome. There were no cases associated with erythema multiforme (von Hebra). Most of the patients were children and young adults, and male patients were more commonly affected. Most patients had prodromal symptoms of an upper respiratory tract infection before the onset of the eruption and an underlying pneumonia. Although the clinical course may be severe and prolonged, the prognosis is uniformly good with complete recovery in nearly all patients. Treatment is largely supportive and the use of antibiotics or steroids (or both) appears to have little effect on the course of the illness. We conclude that M. pneumoniae is the most common infectious agent associated with the Stevens-Johnson syndrome. It is not associated with erythema multiforme of von Hebra.

Bilateral chronic conjunctivitis and corneal scarring in a boy with X-linked hypogammaglobulinaemia

We report an unusual case of bilateral chronic conjunctivitis and corneal scarring in a boy with X-linked hypogammaglobulinaemia (XLH) who did not respond to the usual antibacterial and antiviral therapy. An immunofluorescence test for Chlamydia trachomatis from an eye swab was strongly positive. Within days of commencement of local and systemic tetracycline therapy, he showed marked improvement. Since conjunctival follicle formation, which depends on the presence of a B-cell population, may not occur in XLH, clinical examination in chlamydia conjunctivitis may be misleading and lead to a delay in diagnosis and treatment with resulting corneal complications, unless laboratory evidence of chlamydia infection is specifically sought.

Transverse myelitis associated with mycoplasma pneumoniae: case report

Acute transverse myelitis (ATM) is a disorder of the spinal region of the central nervous system. In the present case, the clinical course showed ATM associated with mycoplasma pneumoniae (MP) and little recovery; the girl was left with a flaccid paraplegia, and thus differed from other cases in the literature which all reported complete or near-complete recovery.