Untreated TB can cause irreversible blindness, say physicians

Physicians have warned that untreated tuberculosis can spread beyond the lungs and affect other parts of the body, including the eyes, potentially causing severe visual impairment and irreversible blindness.

If left untreated or diagnosed too late, they explained that Mycobacterium tuberculosis, the bacterium causing tuberculosis, can spread to the eyes, leading to severe inflammation like uveitis and can result in permanent blindness.

Aside from TB uveitis, the doctors also explained that adverse effects of some medications used in TB treatments can also affect the eye, leading to vision loss if patients are monitored poorly.

TB is a communicable disease that affects the lungs and is caused by bacteria spread through the air when infected persons cough, sneeze, spit, or laugh boisterously, according to the World Health Organisation.

WHO noted that TB remains one of the world’s top infectious killer diseases, with more than 10 million annual infections and one million deaths.

Nigeria ranks first in TB burden in Africa and number six in the world.

Speaking exclusively with PUNCH Healthwise at the sidelines of a three-day training of journalists on drug-resistant tuberculosis coverage and reporting in Abuja organised by the TB Network under the Community-Driven Approach for Transformative Change to Combat Drug-Resistant Tuberculosis (COMBAT DR-TB) Project, the experts urged Nigerians to seek prompt medical help if they experience persistent symptoms associated with TB.

They noted that eye-related complications could include blurred vision, colour vision impairment, and, in severe cases, permanent loss of sight if the condition was not properly managed.

The Head of the Training Department, National Institute of Public Health and Infectious Diseases, Zaria, Kaduna State, Dr. Eunice Jiya-Chitumu, said that aside from TB uveitis, which is rare, drug-induced toxicity from certain TB medications can also lead to permanent vision impairment if the medication is not stopped early.

“Yes, if left untreated, TB uveitis can lead to permanent blindness. While it is not very common in clinical practice—I have only seen about two cases in my years of practice—it remains a potential cause of permanent vision loss if not caught early.

“While TB uveitis is rare, medications used to treat TB can have adverse effects on other organs, including the eye. We call the complication that leads to this blindness an adverse effect of the medication.”

“However, not everyone experiences these side effects. It depends on an individual’s genetic makeup, predisposing factors, or other comorbidities. It is important to distinguish between complications of tuberculosis, which occur by virtue of the disease itself, and adverse effects, which occur by virtue of the medication,” she said.

Jiya-Chitumu, who is a consultant pulmonologist, said the adverse effect from some TB medications leading to vision loss could affect both adults and children.

“Monitoring is essential, which is why patients return monthly for follow-up. Armed with the knowledge that a drug can cause certain issues, we (doctors) actively watch out for symptoms. If a patient begins developing symptoms, there are criteria and protocols for handling adverse effects.

“In certain instances, if a severe adverse effect occurs, the doctor must stop the medication and find an alternative to keep the patient alive. For some adverse effects, we (doctors) can manage them or give an antidote; for others, we are forced to discontinue that specific medication and switch to an alternative,” she said.

She explained that the blindness resulting from adverse effects starts in two ways, urging patients experiencing changes in their vision to seek medical evaluation.

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“It starts in two ways: color vision blindness and optic neuritis, which leads to actual blindness. So, symptoms of blindness may start gradually. A patient might say, ‘Doctor, I cannot see clearly’. One should never wait until it worsens, because once the optic nerve supplying the eye is destroyed by optic neuritis, there is little to nothing that can be done.

“The target is to stay on top of the situation. Every time a patient comes in, we follow a checklist: we use the Snellen chart to assess visual acuity objectively, and we use the Ishihara chart to test for color blindness.

“We do an active search at every patient visit to establish whether their vision has changed compared to their baseline takeoff point. The moment a patient reports or tests positive for blurring or hazy vision, we immediately stop the medication and reassess,” she said.

Jiya-Chitumu, however, said doctors use the Active Drug Safety Management and Monitoring parameters to minimize risk factors of adverse effects of the medications in TB patients’ management.

Aside from permanent vision loss, the consultant pulmonologist listed peripheral neuropathy, severe anemia and bone marrow suppression, abnormal electrical activity in the heart that can lead to sudden cardiac arrest, and hepatotoxicity as other adverse effects.

“Before starting treatment, we conduct thorough counseling to explain the duration of treatment, allay fears, and outline these potential adverse effects,” she said.

Jiya-Chitumu also listed lung fibrosis, coughing up blood (hemoptysis), and difficulty in breathing (Cor Pulmonale) as direct complications of prolonged, unmanaged tuberculosis.

She, however, clarified that TB is treatable and curable, adding that Nigerians with symptoms of tuberculosis should seek prompt treatment.

“Once you notice symptoms, remember that TB is not a death sentence, unless the patient chooses to make it one. It is completely curable. Why not benefit from the fact that this disease can be beaten, instead of allowing it to beat you

“Even though TB is a chronic disease that progresses slowly over time, neglecting or delaying seeking treatment is like dousing oneself in petrol and setting oneself on fire,” she said.

Also speaking, the Drug-Resistant TB Program/Technical Officer, National Tuberculosis, Leprosy and Buruli Ulcer Control Programme, Dr. Adebayo Ekosanmi, stressed that untreated TB puts both the individual and community at risk.

He stressed the importance of actively finding cases through outreaches and following up on presumed TB cases.

“Poor management of susceptible TB cases and non-adherence to TB medicines contributes to drug-resistance, which is more difficult and expensive to manage. One untreated TB patient can infect 10 to 15 others in a year,” he said.

He urged Nigerians to seek medical attention if they experience a persistent cough lasting two weeks or more.

According to him, early detection improves treatment outcomes and reduces transmission.

Ekosanmi stressed that tuberculosis is curable and that treatment is available free of charge at government facilities.