/ 20 November 2015

Undercover tuberculosis: How SA’s top killer slips in under the radar

Despair: Lindiwe Mkwanazi didn’t know what was wrong with her until a biopsy showed she had tuberculosis in her knee. She struggles to walk so her mother
(John McCann/M&G)

Lindiwe Mkwanazi (32) looks past her left leg that’s resting on a low table in the direction of the small box-style TV. Sitting in the one-seater maroon couch, her body is as still as the building she spends almost all of her time in – a run-down block of flats in Mayville, an increasingly industrialised suburb just a few kilometres from Durban’s central business district.

She lives in the tiny second-floor flat with her parents and her 10-year-old daughter Amanda who, dressed in a bright pink tracksuit, stands at the door looking cautiously inside.

Mkwanazi’s face is expressionless, motionless.

But her mother, Sipiwe Khumalo, a large woman in her 50s, remembers Mkwanazi very differently. From the opposite side of the small lounge, Khumalo says five years ago one would have met an active young mother who supported her three young children with a steady job as a security guard.

“When her knee got really painful she went to the clinic but they gave her Panado,” Khumalo says. “I can’t even remember how many times she went, again and again, and only when she could hardly walk they sent her to hospital [in April 2014].”

Within five years she had dropped from a size 42 to a size 28.

Doctors performed a biopsy on Mkwanazi’s knee, removing a small piece of tissue to test for disease.

After searching since 2010 she finally found out what was wrong when the biopsy results came back: she had tuberculosis (TB) in her knee joint.

She began taking treatment but, Khumalo says, once her daughter is cured she does not think the damage will be entirely reversed.

“I think if more people knew that TB can go anywhere in the body people like in Lindiwe’s case, they could get help earlier,” she says.

Non-lung TB
Johan Davis, head of the orthopaedic spinal service at Tygerberg Academic Hospital in the Western Cape, says many people aren’t aware of extrapulmonary tuberculosis – that the bacterial infection can occur in places other than the lungs.

“It is certainly most common in the lungs and this is also the route the disease is spread, which is probably why it gets so much focus,” he says.

In 2011, an estimated 15% of tuberculosis cases in South Africa were diagnosed in places outside the lungs and were more costly to treat and had worse outcomes than tuberculosis of the lungs, according to the World Health Organisation (WHO).

This is higher than China, one of the WHO’s other high-burden countries, where fewer than one in 10 cases are found outside the lungs.

Davis says South Africa’s higher rate is related to the country’s HIV infection rates, which are exponentially higher than China’s.

“The risk of TB outside the lungs rises incredibly when a patient is also HIV-infected – up to 60% of people with both conditions will have musculoskeletal tuberculosis, compared to 3% in the HIV-negative group,” he says. This is because the body’s immune system is less able to combat the tuberculosis bacteria when it enters the lungs, making it “easier to travel”.

Davis, who also lectures and conducts research at Stellenbosch University, says that, in his experience, about half of South Africa’s musculoskeletal tuberculosis cases are found in the spine and the other half is divided between the other joints and bones.

Mkwanazi’s tuberculosis-infected knee is therefore “a relatively rare case in the context of rare cases”, says Davis, who has treated this form of the disease as an orthopaedic surgeon.

Delayed diagnosis
There is no specific prevalence data for joint-related tuberculosis in the country. But a 1995 paper published in the Journal of Bone & Joint Surgery carried a study on all knee-tuberculosis cases in children at Maitland Cottage Hospital in Cape Town from 1979 to 1991. A total of 33 cases were found and, although diagnosis and treatment has changed since then, the authors noted that “early diagnosis is essential to preserve the mobility” of patients. Three children, whose illness was at an advanced stage when they started treatment, were considered disabled because their knee joints could only rotate between 20 and 80 degrees.

Davis says four years is a long time for an active tuberculosis infection to remain undiagnosed. “I do not know this patient but, in my experience, by then the expected destruction of the cartilage in the knee could be so profound she likely won’t really recover in terms of mobility and function.”

Extrapulmonary tuberculosis is more difficult to diagnose than tuberculosis of the lungs and often requires specialists, says Davis.

“In spinal TB, for example, we will surgically remove fluid or tissue from the area for a diagnosis and if the disease is severe the patient may need reconstructive surgery along with the conventional drug treatment.”

He says most extrapulmonary sites are hard to reach and need a certain level of expertise “just to get the tissue” for diagnostic purposes.

Expert care required 
Additional scans and X-rays may also be required, which are often extremely expensive. “It’s incredibly resource-intensive compared to TB of the lungs where getting a diagnostic specimen can be as simple as a patient providing a sputum sample at a clinic.”

The national department of health’s 2014 tuberculosis guidelines state that suspected extrapulmonary tuberculosis cases should be referred to tertiary centres. “But there is a chronic shortage of specialists in the country, which makes the problem even harder to tackle,” says Davis.

The biggest problem is diagnosis: the typical symptoms, widely known and associated with tuberculosis, “particularly coughing up blood”, don’t necessarily appear in cases where the infection is not in the lungs.

“TB is also a great mimicker – it can look like other pathologies. In other parts of the body, especially the musculoskeletal system, it can be confused with forms of arthritis and cancer.”

Often a surgical procedure, in the form of a biopsy, is needed to confirm the diagnosis. 

Davis says there are very few public-sector specialists in the Western Cape capable of doing this in the case of spinal tuberculosis. “I’m not sure about the rest of the country, but my guess is that other provinces are even less resourced.”

Dwindling options
For Mkwanazi, Davis says a knee replacement is likely her only option, but because she is young, even this is not ideal. “A knee replacement has a lifespan of about 10-15 years, and once worn out it might need replacing,” he says.

At home Mkwanazi’s eyes move from the TV and in a lucid moment they connect with Amanda. She closes her eyes and looks away as tears fall slowly down her cheek.

Amanda brings a walker from the bedroom at her mother’s request.

“I can’t do anything anymore. I can’t even go outside, never mind make money for my family. I sit here all day but when my child comes home from school I don’t have any food ready for her,” she says.

Mkwanazi uses the walker’s frame to raise herself. Once up she lifts her head and looks at her audience.

“I suffer most because I can see my mother suffering. She is old, but she is working. Cleaning. Cooking. Looking after me when I should be looking after her. She is the mother to Amanda instead of her grandmother.”

The ins and outs of tuberculosis

Tuberculosis is an infectious disease caused by the bacteria Mycobacterium tuberculosis, which spreads from one person to another through the air when an infected person coughs or sneezes.
In many cases the bacteria is contained by the immune system before it multiplies and causes symptoms. This is called latent tuberculosis. About 10% of people with latent tuberculosis develop active disease in their lifetime and it most commonly involves the lungs. This is the contagious form of the disease. 

But tuberculosis can affect almost any other organ system including bones, lymph nodes and the abdomen. People with weak immune systems such as children and those with HIV or diabetes are more at risk of extrapulmonary (non-lung) tuberculosis. This is because the immune system fails to combat the bug before it reaches the blood stream where it can be carried to other parts of the body. 

Source: British Medical Journal, Best Practice edition, 2014