Obscure fungal infection defies diagnosis

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Obscure fungal infection defies diagnosis

Globe and Mail - Canada

CELIA MILNE

October 12, 2007

http://www.theglobeandmail.com/servlet/story/RTGAM.20071012.wlfungus1

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On Sept. 16, 2004, two days before his 15th birthday, Tyler

Thorkildsen came home from school with such acute pain in his chest

that he could hardly breathe.

Tyler, who lives in the tiny town of Pointe au Baril, 40 kilometres

north of Parry Sound, Ont., was initially diagnosed with pleurisy,

an inflammation around the lungs. When he didn't respond to

treatment, he was sent for X-rays, and a mass was found in one of

his lungs between his eighth and ninth rib.

A physician told the Thorkildsens that he may have lung cancer that

had spread from somewhere else in his body. Tyler collapsed into a

chair in the doctor's office in total disbelief.

Throughout that fall, Tyler underwent countless tests in hospitals,

and his family waited in a fog of worry.

" The waiting was the hardest thing I've ever had to do, " said

Tyler's mom, , who has two younger children as well.

" We couldn't sleep or focus on anything else. "

Luckily for Tyler, one of the many physicians involved in his case

had treated a small girl with a rare fungal infection called

blastomycosis, and the doctor suggested that Tyler be tested for

this condition. Finally, in late November, it was discovered that

blastomycosis was indeed the culprit.

Tyler had acquired the infection simply by breathing in invisible

spores that were in the air near his home. One of the family's three

dogs, Rufus, had the same illness at the same time.

" Blasto, " as it's called, can be treated successfully with anti-

fungal medications. But this obscure illness is so often

misdiagnosed that families spend harrowing months looking for

answers while their loved one gets sicker.

The infection is fickle in several ways. First of all, it lurks in

areas traditionally considered wholesome: the forests of Manitoba

and scenic northwestern Ontario, for instance. Secondly, it has a

variable incubation period, so while people are exposed in the

spring or summer, they may not develop symptoms until the fall or

winter.

Doctors and veterinarians in areas where blastomycosis is endemic

are familiar with it, but those in big cities can be utterly

perplexed by the symptoms. To make matters worse, blastomycosis

mimics many other illnesses such as pneumonia, cancer, skin disease

and even bone and joint ailments.

It's " the great mimic, " says Embil, an infectious disease

specialist in Winnipeg who is one of the world's leading experts on

the disease

For Tyler, getting rid of the bug was not easy because his case was

quite advanced. In December, he was readmitted to hospital to

receive an intravenous anti-fungal drug amphotericin B for several

hours a day. The drug causes swelling, fever and kidney damage, and

Tyler could stay on it only for a few days. He was sent home with an

oral anti-fungal medication called Sporanox (itraconazole), the same

drug at the same dose that the family dog Rufus was prescribed by

the local vet.

For six months, both boy and dog were on Sporanox, and by the summer

of 2005, both were finally well again.

The chances of getting blastomycosis are far greater than being hit

by lightning, but it is certainly not common, Dr. Embil said. " It is

a low-volume disease, " he cautioned. " We don't want to create fear

and panic. "

Hot spots for the illness are Manitoba (15 to 25 cases a year) and

northwestern Ontario (30 to 50 cases a year), as well as the

province's Thunder Bay, Georgian Bay and Temiskaming districts.

There have been a few cases in Quebec, New Brunswick, Nova Scotia,

Saskatchewan and Alberta. In the United States, it is endemic in

Wisconsin, Ohio and the Mississippi River basin.

Blastomycosis is caused by the fungus Blastomyces dermatitidis. It

lives in the soil, and when the soil is stirred up, the spores enter

the body. The infection is more common in dogs than humans, probably

because their snouts are close to the soil.

But you don't have to dig in the soil to get infected. In one case,

a patient in a nursing home who had not gone outside was infected,

possibly through an open window.

Once inside the body, the fungus transforms into yeast, which

multiplies and invades the tissue. It kills its victims 6 per cent

of the time. The fungus is extremely elusive; it may exist in a

certain flower bed one day and the next day be gone. The likelihood

of its being transmitted from one person to another is exceedingly

low.

One of Dr. Embil's most memorable blastomycosis patients was Dean

Hunter, a rock singer from Winnipeg who picked up the infection

while playing a gig in Sioux Narrows, Ont., on Canada Day, 2002.

The blastomycosis infected Mr. Hunter's skull and the lining of his

brain, so physicians thought he had a brain tumour. Luckily, he

crossed paths with Dr. Embil, who helped make the correct diagnosis

of blastomycosis.

Like Tyler in Ontario, Mr. Hunter was treated with intravenous

amphotericin B, and recovered. However, a small pocket of the

infection escaped treatment, and two years later Mr. Hunter got sick

again.

This time, he underwent brain surgery and waited to hear whether he

had cancer or blastomycosis. Thankfully, it was the latter, and

after another round of treatment he recovered again.

Many patients are not lucky enough to find a doctor familiar with

blastomycosis, especially when they become ill far from endemic

areas and many months later.

" Locally in Manitoba and northwestern Ontario, we're aware of the

problem and [treat] it early in the diagnosis, " Dr. Embil said. " But

outside these provinces, it's not the great mimic, it's the great

unknown. "