[Legionnaires' disease with pronounced cerebellar involvement: case report and literature review]

Objective: To summarize the clinical course, neuroimaging and cerebrospinal fluid (CSF) analyses of cerebellar dysfunction in Legionnaires' disease. Methods: A case of Legionnaires' disease with pronounced cerebellar involvement was reported. The related literatures published up to February 2019 were reviewed with "Legionella, legionellosis, legionnaires' disease, cerebellum, cerebellar" as the keywords in CNKI, Wanfang and PubMed databases. Results: A 69-year-old man complained of anorexia and diarrhea for several days. He was subsequently admitted to the hospital after he had fever, ataxia, dysarthria and involuntary tremor. Chest CT revealed right lower lobe pneumonia. Routine urinalysis showed hematuria and proteinuria. Serum alanine transaminase was 52 U/L, creatinine 137 μmol/L, sodium 128 mmol/L, and creatine kinase 6 893 U/L. Cranial CT was normal. Analysis of CSF showed mildly elevated total protein. Legionella colonies isolated from bronchoalveolar lavage fluid was positive by PCR. After initial treatment with moxifloxacin and azithromycin for 7 days, the fever and neurological symptoms persisted. Corticosteroid therapy was administered for 3 days, the fever resolved, whereas the neurological symptoms improved gradually and slowly by 4 weeks of antibiotic therapy. Finally, successive serological test confirmed Legionella pneumophila serogroups 6 and 7 by indirect immunofluorescence. Twenty-one literatures with 23 cases were reviewed, and plus our case, there were a total of 24 cases for analysis. There were 16 males and 8 females, aged from 22 to 71 years. Ataxia and dysarthria were the cerebellar symptoms most frequently reported, occurring in 22 and 18 cases, respectively. All patients had various central and peripheral neuropathies during their illness. Neuroimaging and analysis of CSF was reported in 21 cases. There were no abnormalities in 18 cases of cranial imaging, 1 case with slight hydrocephalus on cranial CT, and 3 cases with hyperintensity in the splenium of corpus callosum on cranial MRI. Eighteen cases of CSF analyses were normal, whereas 1 case with elevated lymphocytes and 3 cases with elevated proteins. Nine cases were eventually identified as Legionella pneumophila serotype 1 by urinary antigen detection, 1 case as Legionella pneumophila serogroups 6 and 7, while the remaining 14 were unknown serotype. Long-term neurologic follow-up showed that 3 cases recovered completely in the first week, while 19 cases improved slowly in the following 3 weeks, and 13 cases had persistent deficits of gait or speech after 3 months. Conclusions: Legionellosis with cerebellar insufficiency is rare. It may be misdiagnosed in the onset of illness. After treatment, there is a trend of slow recovery and neurological symptoms may persist in long-term follow-up.