Discussion
Encephalitis is caused by inflammation of the brain parenchyma causing
neurological dysfunction. The major criterion of encephalitis is an
altered mental status that remains for more than 24 hours without an
alternative diagnosis. Then, there are six minor criteria such as (1)
fever >38oC within 72 hours before or
after symptom onset, (2) new onset of focal neurologic disorder, (3)
abnormality on electroencephalography consistent with encephalitis and
not secondary to another etiology, (4) CSF white blood cells count
> 5 mm2, (5) acute onset of neuroimaging
abnormality consistent with encephalitis, (6) seizures not associated
with a pre-existing seizure disorder. The presence of 2 minor criteria
indicates possible encephalitis and the presence of more than 3 minor
criteria indicates probable or confirmed encephalitis (if the etiologic
agent is confirmed by polymerase chain reaction, serology, or brain
biopsy)8. This case met 2 minor criteria of fever of
38oC 24 hours after symptom onset and the presence of
new onset of focal neurologic disturbances of dysarthria, dysphagia, and
involuntary movements.
Clinical overlap between encephalitis and encephalopathy may occur in
which encephalopathy leads to a clinical condition of altered mental
status that can manifest as disorientation, confusion, or other
cognitive impairment, with or without evidence of brain tissue
inflammation. Encephalopathy can be triggered by some toxic or metabolic
conditions but sometimes occurs in response to infectious agents such as
the influenza virus and Bartonella
henselae 9,10.
Patients with neurotuberculosis have few specific symptoms. Delay in
diagnosis must be considered, usually due to a mild initial neurologic
presentation in most cases, if compared with other infectious
encephalitis11. Based on a report in France, only 20%
of patients had a previous history of tuberculosis. Besides, only 20%
of patients had respiratory symptoms12. In this case,
the patient came with a mild initial neurologic presentation and had no
respiratory symptoms indicated by no history of cough.
Brain MRI is the best device for the diagnosis of encephalitis. CT scan
is used only when MRI is not possible13. There are no
specific features for encephalitis except in brain abscess or
granulomatous lesions cases. A study in France revealed that CT scan and
MRI scan were normal in 8 of 17 patients. It means that there is a
possibility of a diagnosis of tuberculosis being ruled out in cases of
normal imaging12.
There are no conventional lymphatics in the brain, but physiological
studies showed immunologically significant drainage from the brain to
cervical lymph nodes. Perivascular lymphatic drainage from the central
nervous system has an important role in neuroimmunological reactions on
autoimmune diseases and the same mechanism also plays a role in
infection of the central nervous system14–16.
Specific antituberculosis therapy can be associated with the prolonged
onset of action, especially in patients with severe brain
damage17. The standard recommended therapy is
fixed-dose combinations of 4 drugs (isoniazid, rifampicin, ethambutol,
and pyrazinamide) for 6 months intensively. Sudden discontinuation of
treatment is an independent risk factor for mortality in patients with
central nervous system tuberculosis11.