Review Question - QID 105376

This patient initially presented with travel to an endemic area for tuberculosis (TB) and the diagnosis is highly suggested by her symptoms (cough, night sweats, and weight loss) in conjunction with the cavitary lesion on chest radiography. Appropriate treatment is typically RIPE therapy which includes ethambutol which can cause optic neuritis (painful loss of vision) which, when present, requires a different treatment regimen.

Tuberculosis should be suspected in any patient with travel to an endemic area who presents with fever, cough, malaise, and night sweats. The diagnosis of tuberculosis can be made with a positive chest radiograph and sputum acid fast staining. The treatment of tuberculosis is RIPE therapy:

1. Rifampin
2. Isoniazid
3. Pyrazinamide
4. Ethambutol

Ethambutol carries with it the risk of elevating liver enzymes and can cause optic neuritis. Optic neuritis is an acute inflammatory demyelinating injury to the optic nerve. The classic presentation of optic neuritis involves painful, monocular visual loss evolving within hours to a few days. The most common signs on physical examination are an afferent pupillary defect and color desaturation. Optic nerve atrophy can be visible on MRI. Often, these problems persist after treatment, even if vision is recovered. In the case of optic neuritis from ethambutol toxicity, an alternative treatment regimen should be chosen.

Figure/Illustration A is a chest radiograph demonstrating a cavitary lesion in the right upper lobe (red circle).

Incorrect Answers:
Answer 2: CT head would be the best initial step in management for a suspected stroke which may present with sudden onset focal neurologic deficits typically in an older patient with other medical comorbidities.

Answer 3: MRI head could be performed to confirm the diagnosis of optic neuritis. However, such classic symptoms of optic neuritis in the face of ethambutol (an agent that can cause such a condition), warrants discontinuing the offending agent first to avoid further irreversible damage.

Answer 4: Timolol eye drops would be an appropriate treatment in glaucoma which would present with a rock hard eye with a fixed and dilated pupil. The diagnosis of acute glaucoma can be made with tonometry.

Answer 5: Ultrasound of the eye would be appropriate in the workup of a retinal detachment which presents with a "curtain falling down over the eye" loss of vision. It would demonstrate a free flap (the retina).

Bullet Summary:
Ethambutol is used to treat tuberculosis and can cause optic neuritis.