Case 1
A 5-year-old boy with no significant medical or family history was admitted to an outside hospital because of a paroxysmal cough with recurrent high fevers. The highest body temperature recorded was 41°C. He improved after treatment with ceftizoxime and bromhexine. However, on the ninth day of illness, he experienced a seizure of 30-minute duration and was transferred to our facility for further care.
The patient was unconscious on arrival with heart rate 120/minute, respiratory rate 30/minute, blood pressure 115/90 mmHg, and body temperature 37.3℃. On neurological examination, pupils were equal, lower extremity muscle tone was increased, and the Babinski sign was present bilaterally. White blood cell count was 11,310/mm3 (neutrophils, 90.1%; lymphocytes, 5.5%). Hemoglobin concentration and platelet count were 12.0 g/dL and 362,000/mm3, respectively. Erythrocyte sedimentation rate was 28 mm/h and C-reactive protein was 8 mg/L (reference range, < 10 mg/L). Procalcitonin level was 0.41 ng/mL (reference range, < 0.5 ng/mL). Biochemical investigations were normal. Fibrinogen concentration was 1.17 g/L(reference range, 1.8-4 g/L) and D-dimer concentration was 1.45 mg/L(reference range, < 0.3 mg/L). MP-specific IgM serum antibodies were strongly positive. Polymerase chain reaction (PCR) testing of sputum for MP showed 8.63 × 104 copies. Lumbar puncture yielded clear cerebrospinal fluid (CSF) with an opening pressure of 90 mm H2O. CSF white blood cell count was 3 × 106/L and red blood cell count was zero. CSF protein and glucose were 2.3 g/L and 4.0 mmol/L, respectively. CSF PCR testing for MP was negative. CSF cultures were sterile. Plain chest radiography showed bilateral pneumonia with right pleural reaction (Fig. 1A). Brain magnetic resonance imaging (MRI) showed abnormal signal in both occipital lobes, corpus callosum, thalamus, midbrain, pons, and both cerebellar hemispheres that suggested infarction (Fig. 1B and C). Magnetic resonance angiography (MRA) suggested occlusion of the basilar artery (Fig. 1D).
Acute cerebral infarction after MP infection was diagnosed. The patient was treated with thrombolysis, subcutaneous low-molecular-weight heparin (dose adjusted to maintain activated partial thromboplastin time twice the control), intravenous erythromycin (30 mg/kg/day), intravenous methylprednisolone (2 mg/kg/day), and intravenous immunoglobulin. He achieved a partial recovery and was discharged 1 week after his transfer to our facility. At the 1-month follow-up, he was hemiplegic and hypotonic.
Case 2
A 3-year-old girl presented to an outside hospital with high fever and dry cough and was admitted. She was treated with oral erythromycin (30 mg/kg/day) followed by intravenous ceftriaxone (80 mg/kg/day) and methylprednisolone (1 mg/kg/day). Other medical history and family history were unremarkable. Her symptoms did not improve and she developed impaired consciousness on the seventh day after admission. She was then transferred to our hospital for further care.
On arrival, she was unconscious with body temperature 39.2℃, pulse rate 160/minute, respiratory rate 37/minute, and blood pressure 119/63 mmHg. Physical examination showed mild throat congestion, shortness of breath, decreased breath sounds in the right lung, and coarse breathing on the left. Neurological examination showed unequal pupils (left, 5 mm; right, 3 mm) with weak light reflex, increased muscle tone, and hyperactive deep tendon reflexes. Babinski testing was positive bilaterally.
White blood cell count was 11,000/mm3 (67.7% neutrophils, 21.5% lymphocytes). Hemoglobin concentration, platelet count, and erythrocyte sedimentation rate were 11.0 g/dL, 389,000/mm3, and 55 mm/h. C-reactive protein concentration was 9 mg/L (reference range, < 10 mg/L). Serum biochemistry and procalcitonin level were normal. MP IgM antibody titers were positive (1:320). PCR testing for MP in respiratory secretions was positive (2.0 × 105 copies). D-dimer concentration was 18 mg/L (reference range, < 0.3 mg/L). Plain chest radiography showed pneumonia in the right lower lung lobe and a moderate right pleural effusion. (Fig. 2A). Severe MP pneumonia was diagnosed. CSF examination showed the following: nucleated cell count, 3 × 106/L; protein, 0.20 g/L; adenosine deaminase, 1.4 U/L; glucose, 2.99 mmol/L; and chloride, 116 mmol/L. CSF PCR for MP was negative. Blood and CSF cultures were sterile. Brain MRI showed areas of high signal intensity in the thalamus, brainstem, and cerebellar hemispheres on fluid-attenuated inversion recovery and diffusion-weighted imaging.(Fig. 2B and C). MRA showed no filling of the basilar artery (Fig. 2D).
The patient was treated with low-molecular-weight heparin, erythromycin, meropenem, mannitol, glycerol, methylprednisolone, immunoglobulin, and plasma exchange. Her body temperature returned to normal and she gradually regained consciousness. Eventually, the lung inflammation decreased and the pleural effusion was absorbed. She was discharged after 35 days in the hospital. Repeat brain MRI with MRA 4 weeks after discharge showed no significant improvement. One year later, she remained paralyzed, blind, and aphasic but responsive to verbal and painful stimuli.