A 38-yr-old man presented to our emergency room complaining of a 2-week history of productive cough followed by fever on January 10, 2012. He was previously treated for respiratory tract infection at a private clinic, but there was no improvement in his symptoms. His past medical history was unremarkable. He appeared acutely ill. His blood pressure was 90/60 mmHg, temperature 101F, respiratory rate 22/min, and pulse rate 108 beats/min.
On examination, crackles were present in the right lower lung. A chest radiograph showed consolidation in the entire right lower lung field (Fig. 1A). Computed tomography of the chest demonstrated lobar consolidation of the right lower lobe, accompanied by some patchy consolidation in the right middle and left upper lobe (Fig. 1B). No evidence of pleural effusion was observed. Laboratory tests showed normal complete blood cell counts, an erythrocyte sedimentation rate of 65 mm/hr (0-10 mm/hr), and C-reactive protein levels of 19.2 mg/dL (< 0.5 mg/dL). Oxygen saturation was 94% in room air. A urine antigen analysis for Streptococcus pneumoniae and Legionella pneumophila tested negative for both organisms. Procalcitonin level was 0.35 ng/mL (0-0.05 ng/mL). Testing for IgM and IgG antibodies against M. pneumoniae showed elevated titers for both (Table 1). Testing for cold agglutinin disease also revealed positive findings (1:32). A diagnosis of pneumonia subsequent to M. pneumoniae infection was made, and azithromycin was intravenously administered.
On the second hospital day, the patient began to complain of a bilateral headache and diplopia. A neurologic examination revealed the pupils to be equal and responding to light. However, ocular movements were impaired. Prominent limitation of supraduction and mild limitation of abduction were discerned. Head turning and nodding did not influence eye movement. Nystagmus was absent. The visual acuity was not decreased bilaterally, and no signs of meningeal irritation were present. Deep reflexes were decreased. A wide-based ataxic gait was observed, although motor power in the arms and legs was good. Sensation was within normal limits, but a Romberg test to detect poor balance was positive. Brain magnetic resonance imaging (MRI) revealed no abnormalities.
A lumbar puncture was performed and revealed a slightly increased white blood cell count and elevated protein levels (Table 1). Cerebrospinal fluid (CSF) glucose and adenosine deaminase levels were normal. Cultures for bacteria, virus, and fungi were negative, and CSF polymerase chain reaction tests for Mycobacterium tuberculosis, herpes simplex virus, cytomegalovirus, Epstein-Barr virus and M. pneumoniae were all negative. Nerve conduction tests showed decreased sensory nerve action potentials of the right sural nerve. Motor nerve conduction velocity of the right common peroneal nerve was decreased. The blink reflex was normal. Additionally, serological tests for IgM and IgG antibodies against anti-GT1a and GM1 antibody were all negative, but the test for anti-GQ1b IgG antibody was positive.
A diagnosis of FS with antecedent M. pneumoniae pneumonia was made, and treatment of the underlying pneumonia was maintained. Three days later, the patient's body temperature had normalized, and the productive cough was somewhat suppressed. However, headache and diplopia continued. Five days after azithromycin administration, the headache and ataxia began to subside, but diplopia had not resolved. One week after admission, the respiratory symptoms were absent, and diplopia began to improve slowly. Limitation of supraduction resolved earlier than limitation of abduction. Improvement thereafter was gradual, and the patient was discharged 10 days after admission. The ataxic gait and areflexia were completely recovered, but remnant mild diplopia remained at the time of discharge. Follow-up testing for antibodies against M. pneumoniae showed still elevated IgM (8.5 index) and more elevated titers for IgG (> 100 AU/mL) a week after discharge. The patient returned 1 month later for additional follow-up. His ocular examination revealed complete resolution of ocular motility.
Chest radiographic and computed tomography (CT) findings. (B) CT of the chest demonstrated lobar consolidation of the right lower lobe, accompanied by patchy consolidation in the right middle and left upper lobe.