Japanese Case Study Links Patient’s Microscopic Polyangiitis to Silica Dust

Alice Melão avatar

by Alice Melão |

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Silica dust and MPA

Prolonged exposure to the silica dust that construction and other industries generate contributes to the development of the small blood vessel disease known as microscopic polyangiitis, according to a Japanese case study.

Microscopic polyangiitis, or MPA, is one of three types of a category of diseases known as ANCA-associated vasculitis, or AAV. The conditions’ hallmarks are inflammation in, and destruction of, small blood vessels. The other two types are granulomatosis with polyangiitis and eosinophilic granulomatosis with polyangiitis.

Scientists don’t fully understand what causes MPA, but they know that factors like drugs, bacteria, and exposure to environmental hazards are important contributors.

The autoantibodies associated with the disease can strike small vessels in different organs. Patients often experience kidney, lung, or neurological symptoms. An autoantibody is a protein the immune system generates against another protein in the body rather than an invader.

Researchers at Ako Central Hospital, in Hyogo, Japan, reported the case of a patient with prolonged  occupational dust exposure who was diagnosed with MPA. The study in the Journal of General and Family Medicine is titled “Silicosis, then microscopic polyangiitis—antineutrophil cytoplasmic antibodies‐associated vasculitis may be work‐related disease in patients with silicosis.

The 74-year-old retired shipyard worker went to a hospital for fatigue and two weeks of persistent fever. He also reported a dry cough, but no additional symptoms or weight loss.

Doctors had previously diagnosed him with silicosis, a lung disease stemming from long-term exposure to silica dust. The condition is characterized by inflammation and scaring of lung tissue. The patient had worked in a shipyard — a profession that exposed him to the dust — for 43 years until his retirement.

In addition to the fever, he had crackling sounds in his lungs and a rapid breathing rate. Laboratory work showed he also had blood in his urine.

A computed tomography scan showed a dark area in his lungs that led to an initial diagnosis of pneumonia. Doctors gave him an oral antibiotic for a week, but he failed to improve.

Because he continued to experience fever and kidney dysfunction, doctors did additional blood tests. These revealed high levels of autoantibodies against the protein myeloperoxidase, or MPO. This prompted doctors to diagnose him with MPA and a rapidly progressing kidney disease.

Doctors ordered immunosuppressive therapies to counter his MPA. They also instituted aggressive treatment regimens to manage his kidney symptoms. The patient “was discharged from the hospital approximately four months after admission, following improvement of his symptoms,” the researchers wrote.

Scientists have speculated “that particles in environmental silica induce systemic autoimmunity,” the team wrote. “In our present case, the patient developed MPA following 43 years of occupational silica exposure.”

Silica exposure alone could not explain the onset of AAV, the team noted. They said an invasive procedure used to manage his lung condition could have triggered the disease.

“In conclusion, with respect to work-related disease and potential compensation, it is essential to recognize silica exposure as a risk factor for developing AAV such as MPA,” researchers wrote. “Our case emphasizes the importance of primary physicians identifying this relationship in addition to taking a thorough occupational history.”


Jacek Musial avatar

Jacek Musial

It may be interesting, what is follow up for this patient?

Shirley Jones avatar

Shirley Jones

Both my husband & I have been diagnosed with GPA, several years apart by different Drs at different hospitals. We did not meet via a support group. Drs say we are the only known husband & wife couple in the world to both have GPA or Wegener's Granulomatous as it's better known. So Drs stated there must be an environmental or occupational cause for us both to have it. I was diagnosed EVENTUALLY in 1999 & my husband in 2006. Since then I have researched possible causes of autoimmune diseases but especially GPA (WG). For us it's dust from wood composite boards eg MDF, chipboard/particleboard, etc., including cutting/laminating, etc., an asbestos cement board for 5 years daily almost, that was used on ships as wall partitioning, etc. They had to be fire retardant to be on a ship, hence why asbestos cement boards used. They also had to add seperately asbestos fibres to the glue used to stick the laminate on with as it proved difficult to get it to stick to the asbestos cement board. Employees weren't told they were working with asbestos boards & no PPE/masks provided, despite it being obviously extremely dusty, copious amounts of very fine dust too, under PM2.5 which is the most harmful size of dust particle. Exposure was constant & daily as is the nature of wood machining, which is very different to other wood trades, as wood dust emissions are much finer, more copious.
When they found out eventually about the asbestos & asked management, albeit too late, they were lied to & told it was the 'safe' type. There isn't one.
On researching what all these boards contained & how they are manufactured, I found the asbestos cement boards, as you would suspect with a cement product, contained a high % of crystalline silica as well as asbestos. Crystalline silica is known to cause autoimmune disease but more recently asbestos has been linked to causing it too. Apart from that natural wood contains crystalline silica naturally in varying amounts, & wood composite boards are manufactured to contain added crystalline silica in its various elements in the glues, resins, fillers, binders, coatings, so cumulatively a much higher % than admitted overall on any MSDS. To add to that, wood composite boards are made from 'recycled' old contaminated waste wood extracted from construction & demolition wastes so all kinds of additional toxic elements including more c/silica, added by stealth under guise of 'recycling' & are added with no contaminants removed, no prior testing/monitoring, & again no mention at all on any MSDS. They have no idea exactly what they are 'recycling' back into new products that will be emitted in the copious & very fine wood dust emitted when wood machinists or anyone works with these boards. There is also research by the wood industry itself, to prove that the premature blunting of large industrial strength metal diamond & tungsten carbide tipped saw blades, a big problem to the wood industry, is caused by a high % of crystalline silica in wood & wood composite boards. If there is sufficient to cause this level of wear to blades & it can do this to strong metal blades, what does the silica containing wood dust do to the vulnerable lung tissue of those who inhale it daily?
So my research since 2006/7 has been extensive & have spoken to many eminent Doctors, Scientists, Professors, from all over the world since. As I washed his work clothes daily for 42 years I have been exposed also.
WG(GPA) affects us both differently but I suspect that it is governed by how each of us was exposed differently too. He inhaled the silica laden wood dust at source directly as it was emitted from the saw blade as it cut through the silica containing wood products most of which are laminated or have coatings by this stage, so inhaled directly to his lungs in more copious amounts than I was. He has scarring on his lungs, nodules that had grown in 2 years, narrowing of an airway, asthma & psoriasis. Whereas I was exposed to a lesser amount, by the wood dust on his clothing I washed, which was so bad I always had to take it outside first to shake it off. The wood dust would cause me to cough & choke & tasted foul, bitter & was gritty. I often wondered why it was gritty. Now I know. I have mostly nasal septum damage, inflammation & extreme fatigue & also suffer from other conditions such as Fibromyalgia, etc.
This is just a little of our story, but have continued to research, to raise awareness on how harmful any dust is & to campaign on harm caused by workplace exposures or from living next to a dust emitting industrial business.

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