early - stage tuberculous ( tb ) meningitis has no specific symptoms , which may lead to delayed diagnosis and consequently to a worsened prognosis . tb meningitis with dementia as the presenting symptom after intramedullary spinal cord tumor resection without meningitis symptoms or positive tests for tb has not been described . here , we report a fatal case with delayed diagnosis of tb meningitis after intramedullary spinal cord tumor resection . the patient was a 77-year - old man with recurrence of gait disturbance and dysuria . gadolinium - enhanced magnetic resonance imaging ( mri ) revealed tumor recurrence with syrinx formation ( fig . the postoperative course was uneventful and he was discharged after regaining the ability to walk normally . ( a ) t2 mri and ( b ) gd - enhanced mri before the initial surgery ( nine years ago ) , showing the presence of an intramedullary tumor . ( a ) t2 mri after the first surgery , showing total resection of the tumor . ( b ) t2 mri four years after the first surgery , showing regrowth of the tumor . ( c ) t2 mri and ( d ) gd enhanced mri nine years after the first surgery . at 1.5 months after surgery , the patient suffered from dementia with memory loss and diminished motivation and speech in the absence of fever , and was readmitted . tumor recurrence was not seen on mri and blood parameters did not indicate an infection ( white blood cell count [ wbc ] , 7900 /mm ; c - reactive protein level [ crp ] , 0.1 mg / dl ; erythrocyte sedimentation rate [ esr ] , 13 mm / h ) . 2b ) and mri revealed slight enlargement of the ventricles ( mild hydrocephalus ) and the patient was diagnosed with senile dementia by a psychiatrist . however , after two weeks , his symptoms progressively worsened : dementia was more severe , he became disoriented , and his temperature increased to 39c in association with a decrease in consciousness . at that time , the wbc count ( 12000 /mm ) , crp level ( 0.9 mg / dl ) and esr ( 42 mm / h ) were elevated , and meropenem ( 2.0 g / day ) was started . after a further one week , he became comatose and a second mri revealed further hydrocephalus - induced ventricular dilatation ( fig . 2c ) . no tuberculosis bacteria in csf were detected in a polymerase chain reaction ( pcr ) test , -d - glucan in serum was normal , a sputum sample was negative for mycobacterium tuberculosis in a quantiferon - tb gold ( qft - g ) in - tube test , and a tuberculin skin test ( tst ) was also negative . despite the absence of findings of tb meningitis , we suspected that this disease was present from the patient s history , and based on the relatively slow progression of symptoms and the increases in adenosine deaminase ( ada ) , cell counts and protein and the decrease in glucose in the csf . we administered a four - drug regimen ( isoniazid , 0.3 g ; rifampicin , 0.5 g ; ethambutol , 0.75 g ; streptomycin , 0.5 g ) , but the patient died 29 days after admission . subsequently , m. tuberculosis was detected in the second csf sample after a 28-day culture . the patient s wife and son gave informed consent to submit this case study for publication . we encountered a relatively rare case of tb meningitis in an elderly patient that manifested as dementia and impaired consciousness . fever , elevation of inflammatory markers , and signs of fever , neck stiffness , and headache , which are characteristic of meningitis , were notably absent . furthermore , -d - glucan in serum was normal , no bacteria were detected in the initial csf , sputum was negative for mycobacterium tuberculosis in the qft - g in - tube test , and the tst was negative . therefore , we initially assumed age - related dementia or depression , rather than fungal or tb meningitis . common initial symptoms of tb meningitis include internuclear ophthalmoplegia and sensorineural hearing loss , but the disease may be asymptomatic . tb meningitis accounts for only 0.5% of all tb cases , but the mortality is as high as 30% because of delayed diagnosis . in previous reports , < 20% of tb meningitis infections were detected in csf cultures ; pcr had low sensitivity ( 53% ) , compared with microbiological ziehl - neelsen staining and culture methods ( 73% ) ; and the sensitivities of the qft - g and tst were 80% and 28% , respectively . in our case , these tests were negative and m. tuberculosis was detected in a the second csf sample after long - term culture , although the initial findings were negative . thus , a definitive diagnosis of tb meningitis is difficult . in a review by thwaites the sensitivity and specificity of the " vietnam diagnostic rule " ( table 1 ) for tb meningitis were shown to be 86% and 79% , respectively . this rule can help in diagnosis of tb meningitis using simple clinical and laboratory data , and can be used for tb meningitis with low glucose in csf , particularly in settings with limited microbiological resources . retrospectively , the present case had a total score 4 , which is suspicious for tb meningitis . therefore , our case supports the effectiveness of this rule for early diagnosis of tb meningitis , especially for cases without abnormal findings . many secondary cases develop due to a decrease in immunity caused by diabetes or a malignant tumor in the elderly , and many of these cases have no obvious active pulmonary tuberculosis . the patient in the present case had no history of hiv , diabetes , steroid hormone treatment , or malignant tumor , but he had undergone two surgeries for an intramedullary tumor and may have been in a postoperative compromised state . also , in spinal cord tumor surgery , csf leakage may occur after a dura mater procedure , and there is a risk of postoperative meningitis due to long - term drain placement . even if typical symptoms such as headache , fever , and stiff neck are absent , meningitis should be suspected in a patient with deterioration of consciousness and disorientation after intramedullary surgery . the present case indicates that symptoms of dementia after intramedullary spinal cord tumor resection should first be suspected as tb meningitis , even if tests for meningitis are negative . we propose that anti - tuberculosis therapy should be initiated immediately in cases of suspected tb meningitis prior to positive identification in culture .