Mistaken identity: New report highlights the global impact of medical misdiagnosis

December 1, 2011—Researchers have discovered that over a million people worldwide diagnosed with TB go on to develop an incurable but manageable fungal infection which is usually left untreated because it is mistaken for a recurrence of the disease.

In a new report published today in the Bulletin of the World Health Organization, the researchers from University of Manchester and University of Toronto say because the X-ray features and symptoms are so similar doctors often misdiagnose and prescribe the wrong treatment which can lead to tens of thousands of unnecessary deaths.

The fungal infection responsible, chronic pulmonary aspergillosis (CPA), evades the immune system in the lungs progressing slowly and may lie undetected for years until symptoms (weight loss, tiredness, coughing and bleeding) start to develop. By then it is often too late to treat successfully.

50 per cent of all patients who develop it are unlikely to survive for more than five years, a similar outlook to many cancers.

Now, the report's authors are calling on the World Health Organisation and others to provide awareness training, particularly for medics in Africa, India and China where under diagnosis of CPA is even more common than in Western countries because of the burden of TB.

The team was led by Professor David Denning, Director of the National Aspergillosis Centre at the University Hospital of South Manchester. He says the report highlights huge global variations in frequency and survival (see the table below). "For example, only 17 per cent of referred CPA patients in Manchester had underlying TB compared with 93 per cent in Korea. This variation reflects differences in diagnosis and inappropriate therapy—or none at all. Identifying CPA early in patients is only possible by means of microbiological testing for Aspergillus antibodies."

Professor Donald Cole, Associate Professor & Division Head of Global Health at the University of Toronto's Dalla Lana School of Public Health, is an expert in environmental and public health. He believes doctors have probably underestimated the worldwide burden of CPA. "We based our estimates on WHO data but the information is robust in some countries but not others. Under reporting is common, especially in countries such as China."

Professor Ian Jacobs is Director of MAHSC—a partnership between the NHS in Manchester and the University of Manchester—and has recently included global health as a focus for its work. He is backing the call for WHO and the leaders of countries in Asia and Africa to take action. "TB is a major scourge worldwide, and to find that over a third of a million people each year then develop an incurable and ultimately fatal fungal complication—which could be diagnosed and treated—demands action."

Read the paper here: http://www.who.int/bulletin/volumes/89/12/11-089441/en/index.html

We at UHSM have a case study of a 35 year old man who contracted TB while he was working as a nurse in his home country of Kenya. He underwent treatment and now lives in Manchester. In 2008, he discovered he had CPA and has been undergoing treatment. His prognosis is good and he is happy to tell his story.

For UK: Susan Osborne, Director of Communications, University Hospital of South Manchester NHS Foundation Trust, t: 0161 291 4972, m: 07836229 208, e: susan.osborne@uhsm.nhs.uk

For CANADA: Jim Oldfield, Communications Officer, University of Toronto Faculty of Medicine, t: 416-946-8423, e: jim.oldfield@utoronto.ca

Aspergillus is an airborne fungus that everyone breathes in daily. In those who are immunosuppressed, for example, those undergoing organ transplantation or treatment for haematological malignancies it causes a disease called invasive aspergillosis (IA)). In those with damage in their lungs such as tuberculosis or COPD, it can cause chronic pulmonary aspergillosis a slowly progressive and destructive disease of the lungs. In those with asthma or cystic fibrosis it can cause an allergic condition of the lungs with wheeze, mucous plugging of the airways and loss of lung function called allergic pulmonary aspergillosis.

There are estimated to be over 200,000 IA cases annually worldwide and over 10M patients at risk. Mortality rates vary by patient group ranging from 30% to 85%. For CPA there are estimated to be over 3M cases (as demonstrated in part by this report). For ABPA in asthma there are estimated to be over 4M patients worldwide.