Mycoplasma pneumoniae and central nervous system complications: a review

Mycoplasma pneumoniae: nervous system complications in childhood and review of the literature

Mycoplasma pneumoniae is an important pathogen which causes nervous system disorders during or after the course of a respiratory tract infection. The exact pathogenic mechanism which causes neurological disorders still remains unknown. Although meningoencephalitis and acute disseminated encephalomyelitis are common complications, there are few cases of acute transverse myelitis and isolated abducens nerve palsy associated with M. pneumoniae infection in childhood. The association between ocular myasthenia gravis and M. pneumoniae infection has not been described before. Here, we describe five patients with different nervous system complications associated with M. pneumoniae infection and discuss the pathological features of central nervous system involvement.

Role of Mycoplasma pneumoniae in pediatric encephalitis

A retrospective study investigating all the infectious encephalitis cases hospitalized at the pediatric intensive care unit of Edouard Herriot University Hospital in Lyon, France, was carried out in order to estimate the prevalence of Mycoplasma pneumoniae in acute childhood encephalitis. From January 2001 to December 2005, the cases of 29 children were selected and reviewed. M. pneumoniae related encephalitis was considered as probable in five cases (17%) on the basis of positive serological tests or positive polymerase chain reaction (PCR) tests in throat or nasopharyngeal swab while the PCR tests performed from the cerebrospinal fluid were negative. This study suggests that M. pneumoniae may be a major cause of infectious encephalitis in children as well as enteroviruses or Epstein-Barr virus detected in five and three cases, respectively.

Mycoplasma meningitis resulting in increased production of cerebrospinal fluid: case report and review of the literature

PURPOSE

We report a case of increased cerebrospinal fluid (CSF) production in a child with concomitant mycoplasma meningitis.

MATERIALS AND METHODS

This 4-year-old boy presented with a 2-week history of body aches, malaise, and headaches. He developed sudden onset of obtundation, apnea, left eye deviation, and bilateral dilated and unreactive pupils. A ventriculostomy was placed initially for a poor neurologic examination in the setting of likely meningitis. Initial intracranial pressure was high, and CSF production was supraphysiologic for the first few days of empiric, broad-spectrum treatment. Mycoplasma meningitis was diagnosed. The ventriculostomy was weaned after adequate treatment for mycoplasma meningitis.

RESULTS AND CONCLUSIONS

At 4 months follow-up, the child remains shunt-free with only mild cognitive-linguistic impairment. Untreated mycoplasma meningitis may cause raised intracranial pressure (possibly as a result of increased CSF production) and result in a poor neurological examination. In this setting, CSF diversion in the form of an external ventricular drain may be beneficial to preserve neurologic function during treatment with antibiotics.

Mycoplasma pneumoniae encephalopathy: recovery after intravenous immunoglobulin

In a case of Mycoplasma pneumoniae encephalopathy in a 7-year-old girl, the microorganism was identified by serologic and pharyngeal-swab polymerase chain reaction methods. Failure to detect or isolate the pathogen in the cerebrospinal fluid and the significant rapid clinical recovery of the patient after intravenous immunoglobulin administration suggest an immune-mediated mechanism. In critically ill patients with M. pneumoniae encephalopathy, prompt intravenous immunoglobulin treatment may be beneficial and can be considered as a primary or alternative therapeutic approach, especially when use of corticosteroids is insecure.

[Optic neuritis attributable to Mycoplasma pneumoniae]

Optic neuritis (ON) is an inflammatory disease whose etiology remains obscure. We report a case of ON attributable to Mycoplasma pneumoniae (MP). A 26-year-old man presented a sudden onset bilateral loss of visual acuity, without any history of pulmonary or ear-nose-throat infection. Diagnosis of optic neuritis was made on the basis of visual field loss, though optic disks and visual evoked potentials were normal. Color vision could not be assessed due to a congenital dyschromatopsia. The neurological examination was normal. On magnetic resonance imaging, there was no enhancement or enlargement of optic nerves, but a demyelinating lesion of the cervical spinal cord. Lumbar puncture revealed lymphocytic meningitis with 60 white blood cells, all of them being lymphocytes. Oligoclonal bands were presents in the CSF. With no evidence of any other infection or auto-immune disease, the diagnosis of Mycoplasma pneumoniae infection was established due to the presence of Mycoplasma pneumoniae specific IgM antibodies. Outcome was quite favorable within three months without treatment. Neurological symptoms--encephalitis, meningitis, polyradiculitis, or more rarely ON or cerebella ataxia--are the main extra pulmonary manifestations of Mycoplasma pneumoniae infection. Search for anti-Mycoplasma pneumoniae IgM antibodies should be performed routinely when On is diagnosed.

The epidemiology of acute encephalitis

Encephalitis means inflammation of the brain matter. Despite being a rare condition, encephalitis is of public health importance worldwide because it has high morbidity and mortality. Yet, many details about its epidemiology have yet to be elucidated. This review attempts to summarise what is known about the epidemiology of the infective causes of encephalitis and is based on a literature search of the Medline archives. Infection is the most common cause identified, with viruses being the most important known aetiological agents. Incidence varies between studies but is generally between 3.5 and 7.4 per 100,000 patient-years. Encephalitis affects peoples of all ages; however, incidence is higher in the paediatric population. Although both sexes are affected, most studies have shown a slight predominance in males. Encephalitis occurs worldwide; some aetiologies have a global distribution (herpesviruses) while others are geographically restricted (arboviruses). Although definite epidemiological trends are evident, it is difficult to make generalisations as few population-based studies exist, most cases are not reported to health authorities, and many possible pathogens are implicated but in most cases a cause is never found. A better understanding of the epidemiology of this devastating disease will pave the way for better prevention and control strategies.

Mycoplasma pneumoniae-an emerging extra-pulmonary pathogen

Mycoplasma is a well-recognised pathogen that colonises mucosal surfaces of humans and animals. Mycoplasma pneumoniae infects the upper and lower respiratory tracts of children and adults, leading to a wide range of respiratory and non-respiratory clinical conditions. M. pneumoniae infection is frequently considered in the differential diagnosis of patients with respiratory illnesses, and is commonly managed empirically with macrolides and fluoroquinolones. This contrasts with patients who present with non-respiratory symptoms in the context of a recent or current unrecognised M. pneumoniae infection, for whom this pathogen is rarely considered in the initial differential diagnosis. This review considers the microbiological, epidemiological, pathogenic and clinical features of this frequent pathogen that need to be considered in the differential diagnosis of respiratory and non-respiratory infections.

[Acute disseminated encephalomyelitis and severe post-infectious encephalitis]

L’encéphalomyélite aiguë disséminée, acute disseminated encephalomyelitis, (ADEM), est une maladie inflammatoire démyélinisante du système nerveux central (SNC). Également appelée encéphalite post-infectieuse, elle est liée à un mécanisme auto-immun et s’installe typiquement dans les suites d’une infection après un intervalle libre de deux à 30 jours. L’ADEM est caractérisée cliniquement par un tableau d’encéphalopathie aiguë avec signes neurologiques multifocaux. Les patients peuvent nécessiter une admission en réanimation du fait de troubles de la conscience, de crises convulsives ou d’une tétraplégie. L’analyse du liquide céphalorachidien peut montrer une méningite lymphocytaire, mais on ne retrouve pas d’infection évolutive du SNC. Il n’existe pas de marqueur spécifique de la maladie et l’imagerie par résonance magnétique cérébrale est essentielle au diagnostic, permettant de mettre en évidence des lésions multifocales de la substance blanche du SNC sur les séquences T2 et FLAIR. Le traitement de l’ADEM est basé sur les corticoïdes fortes doses, éventuellement associés aux immunoglobulines polyvalentes ou aux échanges plasmatiques. Le pronostic est généralement favorable sous traitement, des récurrences peuvent néanmoins survenir dans l’évolution.

Use of therapeutic plasma exchange in the management of acute hemorrhagic leukoencephalitis: a case report and review of the literature

BACKGROUND

Acute hemorrhagic leukoencephalitis (AHLE) is a rare, fatal, central nervous demyelinating disease characterized by a rapid fulminant clinical course. Successful management requires early diagnosis, aggressive management of cerebral edema, and immunosuppression. Therapeutic plasma exchange (TPE) is infrequently used and commences after initial management fails.

CASE REPORT

A 31-year-old man presented with right arm weakness, whose symptoms rapidly progressed to hemiplegia and aphasia. The patient was initially managed with glucocorticosteroids. Decompressive craniotomy and brain biopsies were performed when his intracranial pressure increased. Brain biopsy findings were consistent with AHLE. Mycoplasma pneumonia immunoglobulin G and immunoglobulin M serologies revealed recent infection. Despite surgical and medical management, he decompensated on Day 11, and TPE was initiated. The patient received a total of 10 TPE treatments. On the fourth day of TPE treatment, he was extubated. Twenty-one days after TPE began, he was ambulating with near normal muscle strength and was discharged. Four months after initial presentation, the patient has normal strength and is working full-time.

CONCLUSIONS

AHLE has a fulminant course requiring accurate and rapid diagnosis. Successful therapy requires aggressive management of intracranial pressure and immunosuppression. Two other reports of AHLE document successful management with TPE. Each of these patients survived with minimal neurologic impairments. Given the likely immune-mediated nature of this disease, combined treatment of steroids, surgery, and TPE may lead to shorter hospital stays and improved neurologic outcomes. Clinical studies are needed to further study the effect of TPE on neurologic outcome in AHLE.

Pre- and post-encephalitic neuropsychological profile of a 7-year-old girl

Our understanding of the neuropsychological effects of encephalitis has largely come from studies in which the level of premorbid functioning is estimated. Moreover, data on the neuropsychological effects of encephalitogenic pathogens other than the herpes simplex virus (HSV) are scant. We present the case of a 7-year-old girl who had intellectual and language assessment seven months prior to the onset of non-HSV encephalitis (possible aetiology: Mycoplasma pneumoniae), and again post-encephalitis. MRI post-illness demonstrated basal frontal, temporal and (limited) parietal damage. Details of speech, psychological and neuropsychological assessments were also documented. Pervasive changes were apparent in the domains of personality, behaviour, emotionality, attention, executive function, speech, language and memory. The patient's profile appears to differ most from that seen following typical HSV encephalitis with respect to marked executive and attentional difficulties. Her deficits appear to reflect both her acute basal brain injury and more diffuse insult, probably caused by postinfectious encephalitis.

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.

[Should presumptive meningoencephalitis treatment in adults be active against Mycoplasma pneumoniae?]

INTRODUCTION

Meningoencephalitis is the most common central nervous system complication caused by Mycoplasma pneumoniae. Its frequency is probably underestimated.

OBJECTIVE

The study's aim was to determine the retrospectively incidence of M. pneumoniae meningoencephalitis among other cases of encephalitis diagnosed in infectiology, neurology and ICU at the Clermont-Ferrand University hospital in 2004 and 2005.

DESIGN

A case of meningoencephalitis was defined by encephalopathy (altered level of consciousness and/or change in personality), with one or more of the following symptoms: fever, seizure, focal neurological findings, meningitis, electroencephalography or neuroimaging findings consistent with encephalitis. Tumor and hematoma diagnosed by scan were excluded. M. pneumoniae was considered as a possible cause when patients had positive serological test (IgM Elisa) and/or positive PCR results for the CSF.

RESULTS

Four (8.3%) patients among 48 cases of encephalitis could have been caused by M. pneumoniae. All except one convulsed initially. Pneumopathy was found in two patients. All received a specific treatment later. Antibiotics seemed to influence evolution in only two patients. These 4 cases appeared during an epidemic between November 2004 and August 2005: 48 hospitalized adults had positive serological test for M. pneumoniae in 2005 and 15 in 2004, whereas the number of tests was the same in 2004 and in 2005.

CONCLUSIONS

M. pneumoniae should be investigated as a cause of meningoencephalitis if initial tests are negative, if patients have respiratory symptoms and in case of epidemic. Presumptive treatment of meningoencephalitis should include an antibiotic active against M. pneumoniae.

Mycoplasma pneumoniae pneumonia: differential diagnosis by computerized tomography

OBJECTIVE AND BACKGROUND

This study was designed to clarify chest computerized tomography (CT) findings of Mycoplasma pneumoniae pneumonia facilitating differential diagnosis from CAP (community acquired pneumonia) caused by other organisms.

METHODS

We retrospectively reviewed the CT findings of 36 patients (median age 33 years, 15 males, 21 females) with serologically proven M. pneumoniae pneumonia and 52 patients (median age 61 years, 37 males, 15 females) suffering from CAP with no serological evidence of M. pneumoniae infection. The CT images were analyzed by experienced pulmonologists.

RESULTS

The most common finding in the M. pneumoniae pneumonia group was bronchial wall thickening, when we compared it with the CAP group (p<0.0001, Fisher's exact probability test). In the CAP group infected with other organisms, dense consolidations with air bronchograms were more frequent than any other findings (p=0.0279, chi-square test).

CONCLUSIONS

The diagnosis of M. pneumoniae pneumonia would appear to be reliable when we found bronchial wall thickening in the chest CT images.

[Mycoplasma pneumoniae infections: retrospective study in Basse-Normandie, 1997-2005. Epidemiology--diagnostic utility of serology and PCR for a rapid diagnostic]

But de l'étude

L'objectif de cette étude est de décrire l'épidémiologie des infections à Mycoplasma pneumoniae (Mpn) en Basse-Normandie par une analyse rétrospective des résultats sérologiques et PCR, et de valider ces deux outils pour un diagnostic précoce de ces infections.

Patients et méthodes

De 1997 à août 2005, 6156 sérums et 6123 prélèvements respiratoires ont été réalisés chez des patients hospitalisés et analysés pour une recherche d'infection à Mpn, soit par PCR, soit par sérologie Elisa, soit par les deux. Pendant la période épidémique (2004–2005), les résultats de 1489 patients ont été analysés.

Résultats

Sur les neuf années, la séroprévalence moyenne se chiffre à 40,4 % et 525 cas d'infection ont été diagnostiqués par PCR et/ou sérologie, se profilant nettement sous l'aspect de deux pics épidémiques espacés de sept ans. Pendant la période épidémique, la séroprévalence augmente (50,2 %) et l'incidence est de 8,3 %. L'analyse des caractéristiques épidémiologiques des 124 cas diagnostiqués montre : une prédominance chez l'enfant et l'adulte jeune, une fréquence saisonnière estivohivernale, l'existence de co-infection virale. L'analyse des résultats chez 36 patients ayant bénéficié des deux tests diagnostiques, PCR et sérologie, montre une concordance dans seulement 41,7 % des cas.

Conclusion

Les infections à Mpn surviennent sur un mode endémo-épidémique, avec une incidence élevée lors des pics épidémiques, particulièrement chez l'enfant. Nous disposons actuellement d'outils bactériologiques performants permettant de réaliser un diagnostic précoce et fiable. Chez l'enfant, il convient d'associer une sérologie (IgM) et une PCR sur un prélèvement nasopharyngé ; chez l'adulte il faudra privilégier la PCR.

[Mycoplasma infections]

Mycoplasmas are prokaryote microorganisms without cellular wall, that usually colonize the respiratory and urogenital mucosae. The pathogenic species for mankind are Mycoplasma pneumoniae, that produce respiratory infections, among them pneumonia, and M. genitalium, M. hominis and Ureaplasma urealyticum, that produce urinary and genital infections. The diagnosis of these infections is fundamentally based on serology, since the culture of these germs is very laborious. In a near future, the antigen or DNA detection molecular techniques will probably permit a much faster and reliable diagnosis. The tetracyclines and fluorquinolones have excellent activity against these microorganisms.

Mycoplasma pneumoniae central nervous system infections

PURPOSE OF REVIEW

Mycoplasma pneumoniae is associated with a wide range of central nervous system diseases, most importantly with childhood encephalitis. This review summarizes and discusses recent findings in the field of M. pneumoniae central nervous system infections in context with previously published findings, with reference to clinical spectrum, pathogenesis, diagnosis, and treatment.

RECENT FINDINGS

Further insight into the pathogenesis has been provided by studies on cytokine production and autoantibody formation. Some new manifestations have been described (e.g. Kluver-Bucy syndrome, intracranial hypertension). Anecdotal descriptions on the association of M. pneumoniae with uncommon neurologic diseases remain to be confirmed by additional reports, however, especially when aetiologic diagnosis relied exclusively on serology. New knowledge on treatment options targeting the immune system has been provided by isolated reports. Recent diagnostic advances refer to general methods (polymerase chain reaction, serology), without specific reference to neurologic disease.

SUMMARY

M. pneumoniae must be considered as causative agent of various neurologic diseases. The recent literature shows, however, that the clinical spectrum of M. pneumoniae central nervous system disease is still not well defined. In addition, the main future challenges are the investigation of the pathogenesis of M. pneumoniae central nervous system disease and the establishment of therapeutic approaches.

Kluver-Bucy syndrome after mycoplasmal bronchitis

Kluver-Bucy syndrome is a rare neurobehavioral condition characterized by visual agnosia, excessive oral tendencies, hypermetamorphosis, placidity, altered sexual behavior, and changes in dietary habits. This description of a 14-year-old boy presenting with complete Kluver-Bucy syndrome after Mycoplasma pneumoniae bronchitis is the first such case report. MRI revealed left temporal horn dilation and asymmetry of both temporal lobes. We hypothesize that the pathophysiology of our case is immune-mediated damage by M. pneumoniae resulting in vasculopathy.