CHSU Discovery

Abstract 

Introduction: The treatment for pulmonary tuberculosis (TB) is 4 months of rifampin, isoniazid, pyrazinamide, and ethambutol (RIPE) followed by 2 months of rifampin and isoniazid only (RI). Anti-TB drugs and TB can both cause encephalopathy, thus a potential diagnostic challenge. We present a case of acute encephalopathy in a patient with active TB while on RIPE therapy. 

Case Presentation: A 66-year-old female with recent diagnosis of pulmonary tuberculosis on RIPE therapy brought in by family due to confusion, generalized weakness, and apraxia. She was reported by family to have poured coffee on the table top instead of a mug. On admission she was seen inaccurately grasping for objects. No prior history of similar episodes or mental health disorders. Patient was admitted for acute encephalopathy and further workup. 

Initially, patient was increasingly restless and unable to stand unassisted. Due to attempts to get out of bed, and need for MRI, she was given multiple sedatives without efficacy. Later that night, patient had 2 episodes of tonic-clonic seizures, was intubated for airway protection, and upgraded to ICU. Patient’s chemistry panel and ammonia was not suggestive of metabolic imbalances contributing to encephalopathy. Imaging of the brain was negative. Urine drug screen was negative. Active TB was confirmed with AFB. Lumbar puncture was done and ruled out TB encephalitis, and other infectious etiologies. After primary source of psychosis was ruled out, all anti-TB drugs were discontinued. Symptoms subsided after discontinuation and therapy was re-introduced subsequently starting with isoniazid, then rifampin, which did not cause relapse of psychotic symptoms. It was thereby theorized that ethambutol could have been a factor in worsening psychosis. 

Discussion: This patient had drug-related psychosis related to anti-TB meds, namely ethambutol. Anti-TB drug related psychosis has been reported: isoniazid has shown a temporal association in acute psychosis, and cycloserine have also been implicated in psychosis and seizure activity. Ethambutol is associated with optic neuritis. Ethambutol-induced psychosis is rare, known to interfere with metabolic processes essential for the normal functioning of the neuron. Only 2 other case reports demonstrate ethambutol-induced psychosis, both patients improving after discontinuing ethambutol. A stepwise approach to re-introducing RIPE therapy reported improvement and eventual resolution of patients psychotic symptoms in previous studies and similar management was implemented in our patient. 

Conclusion: Ethambutol can induce psychosis as a side effect for TB therapy.