In normal pregnancy, during the first trimester (first 12 weeks following conception), nausea and sometimes vomiting commonly occurs leading to deterioration in work performance. Fatigue is also a common problem not only in the first 12 weeks but also during the latter stages of pregnancy. This may be exacerbated by shift work and long hours at work.

In the second trimester (13 – 26 weeks), many pregnant women experience musculoskeletal problems because of the physical changes in their body including weight gain, increased girth and changes in their postures as a result. Towards the end of the second trimester, more physical difficulties may be experienced such as reduction in affective arm reach, balance becomes less stable and falls are more common due to the body’s change of centre of gravity. Dizziness and fainting may also occur particularly in hot environment or with prolonged standing.

In the third trimester (after 29 weeks), the problems of the second trimester continue but fatigue becomes more pronounced and is often worsened by insomnia. There may be a variety of aches and pains, constipation, haemorrhoids, varicose veins, bladder problems which all may affect a women’s work capacity.

People with hearing loss may have difficulty listening to normal conversations, hearing in the presence of background noise, using communication systems, hearing warning signals and localising the direction of a sound source. It may also affect their ability to use hearing protection.

Significant hearing loss can affect fitness for work in jobs that require good communication or where catastrophic consequences may result (ie. serious injury due to failure to hear a warning signal). Exposure to excessive noise may further compromise hearing ability.

In certain occupations where there are specific hearing requirements, governing organisations often develop medical standards. For example, the National Road Transport Commission has hearing guidelines for commercial drivers.

Where there is no such medical standard, a person with significant hearing loss needs to be assessed on their ability to undertake the inherent requirements of the job safely and effectively with or without modifications which do not cause undue hardship on the employer (e.g. installation of visual warning systems). Otherwise, denying the person a job based on hearing loss may be deemed discriminatory.

In these cases the extent of the hearing loss should be assessed clinically and/or audiometrically but the disabling affects of hearing loss should be assessed practically in the work scenario. The disabling effects of hearing loss are dependent on multiple factors including type of hearing loss, the distance from the sound source, background noise, job experience etc. Job experience and skill may outweigh any potential disadvantage suggested by pure tone audiometry done in a controlled environment which may be unrelated to the real work setting

What drugs do we look for?

The main drugs looked for in a standard urine drug and alcohol screen are:

What are the cut-off levels for a positive result?

The following cut-off levels are used for reporting drugs of abuse in urine.

* cut off level taken from the AS/NZ 4308:2008 standard.

How long do these drugs stay in the system?

Some drugs are cleared rapidly from the system while others can persist for a long time. Regular use of a drug can also mean it stays in the system longer.

As a guideline most common drugs have the following clearance rates.

Will passive smoking lead to a positive result for Cannabis?
The cut off level for Cannabis has been chosen to exclude passive smoking as a cause for a positive result.

A donor will not test positive for Cannabis as a result of passive smoking unless the exposure has been extreme. The donor will be aware of such exposure.

What does it mean if the urine is dilute?

A chemical called creatinine is present in urine and this is measured to see if the sample is dilute. If the donor drinks too much water, the urine may become very dilute.

A dilute sample will still be tested and positive results will be reported. Negative results will be marked as unsuitable and a repeat sample will be requested.

If a donor continues to present dilute samples with no reasonable medical explanation then intentional dilution to avoid detection must be considered.

What does it mean if the temperature check fails?

A freshly produced urine sample should be at body temperature.

If the temperature is outside expected values then sample substitution or tampering must be considered. The temperature check may also fail if an insufficient volume of sample is produced.

If the temperature check fails it will be noted on the report and a repeat collection will be recommended.

Is the sample checked for masking agents?

All urine samples are checked in the laboratory for compounds commonly used to interfere with drug testing. If interfering compounds are detected this will be indicated on the report.

What is the difference between a screen and a confirmation?

The initial screen for drugs uses an immunoassay that looks for selected drug classes. Positive screening results can be caused by prescription and over the counter medications and so it is important to note any recent medications on the chain of custody form before the testing is done.

Confirmatory testing is done using a technique called Gas Chromatography with Mass Spectrometry (GC-MS). This is a highly accurate technique that is able to specifically identify and quantitate individual drugs that may be present.

All urines are first checked by a screening test using immunoassay. This is an analytical process that uses specific antibodies to detect compounds of interest. When screening for drugs of abuse we have specific cut-off levels defined by the Australian standard AS: 4308.

The AS: 4308 standard also requires confirmatory testing to be done on samples where the screening test detects a compound above the specific cut-off value.

Confirmatory testing by Gas Chromatography with Mass Spectrometry (GC/MS) or an approved equivalent should be done on all samples where a compound is detected by the screening test. The GC/MS allows us to look for specific compounds and can determine if certain drugs are present and if this is consistent with any stated medication. This also allows us to distinguish between legally available compounds and illicit drugs.

Confirmatory Testing

Opiates
Codeine and Morphine are the main Opiates looked for during confirmatory testing. In addition 6-Monoacetyl Morphine (Heroin metabolite) can be looked for if the screening test indicates this compound may be present. Codeine breaks down to Morphine in the body and the presence of both in the urine is consistent with the use of a medication containing Codeine.

Heroin breaks down to 6-Monoacetyl Morphine and then to Morphine. If 6-Monoacetyl Morphine is detected by confirmatory testing above the cut-off level of 10 ug/L this result is consistent with recent Heroin use. Very high levels of Morphine are usually seen with the use of Morphine or Heroin. Prescription access to Morphine is very restricted and claims of its legal use may require verification.

Poppy seed ingestion can also lead to detectable levels of Morphine in the urine. If poppy seeds have been ingested, Morphine is usually less than 2000 ug/L however Morphine has been reported as high as 11571 ug/L after poppy seed consumption.

The cut-off level for confirmatory testing for Codeine and Morphine in urine samples is 300 ug/L.

Amphetamines
The Amphetamine type substances are a large family of compounds that include both lawfully available and illicit drugs. Ephedrine and Pseudoephedrine are found in “Cold and Flu” medication and can be obtained over the counter from a pharmacist. The cut-off level for the detection of Ephedrine and Pseudoephedrine is 500 ug/L.

Phentermine and Amphetamine (also called Dexamphetamine) are available on prescription. The confirmatory cut-off levels are 500 ug/L and 150 ug/L respectively. Both can also be drugs of abuse and claims of legal use should be verified.

Methamphetamine (ICE, Crystal Meth), MDMA (Ecstasy) and MDA are not present in medications and their use is unlawful in Australia. The confirmatory level for these compounds is 150 ug/L.

Cannabis
The Cannabis cut-off for GC-MS is 15 ug/L which is much lower than the cut-off for the immunoassay screening test. This is because the screening test looks for a family of chemicals produced as a result of Cannabis use. The GC-MS specifically looks for the 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (Carboxy-THC) which is the main by-product of cannabis use found in the urine. Carboxy-THC above the cut-off level of 15 ug/L is consistent with Cannabis use.

Cocaine
The GC-MS for Cocaine looks for two main breakdown products of cocaine metabolism which are Benzoylecgonine and Ecgonine methyl ester. The presence of either of these compounds above the cut-off level of 150 ug/L is consistent with recent Cocaine use.

Benzodiazepines
Benzodiazepines are a common prescription medication. GC-MS or LC-MS confirmatory testing can determine if compounds detected in a urine sample are consistent with Benzodiazepine use. In addition the results can be compared to the stated medication to indicate if results are consistent. Different Benzodiazepine medications will result in different breakdown products being detected in the urine sample. The cut-off level for urine Benzodiazepines in confirmatory testing depends on the compound and may be 100 ug/L or 200 ug/L

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The degree of nickel allergy and the development of dermatitis varies. It may occur after a brief contact with a nickel product, or it can occur after many years exposure to a nickel containing material.

The dermatitis develops either in the area where the product comes in contact with the skin, or sometimes people develop blistering dermatitis on their hands and feet known as pompholyx.

Nickel allergy is diagnosed by the clinical history and by allergy patch testing.

The treatment for nickel dermatitis involves the use of potent topical steroids to the area of dermatitis. This may be used under wet compresses to aid in penetration, and to dry up the weepy skin. If the nickel dermatitis is severe or widespread, systemic steroids may be needed.

It is essential to avoid nickel containing metals once nickel allergy has been confirmed on history and with patch testing. To test if metal items contain nickel, a nickel testing kit containing solutions of dimethyglyoxime and aluminium hydroxide are mixed together, and in the presence of nickel, it turns a pink colour. Unfortunately desensitization to nickel with injections or pills is not possible. Nickel allergy is difficult to prevent once it occurs as nickel products are found so commonly in everyday use.

Dr. Ernest Tan
MBBS FACD
Consultant Dermatologist
Burswood Dermatology
87 Burswood Road
Victoria Park WA 6100
Australia

Tel: 618 9470 3064
Fax: 618 9470 4479

The normal ankle joint, like most joints in the body, is lined by hyaline articular cartilage. This is a firm smooth surface which allows the two surfaces of the joint to glide smoothly together during movement. Any damage to this articular surface can result in chondral injuries.

Mechanism of Injury

The ankle is commonly involved in work-related injuries. The articular or chondral surface is particularly prone to inversion injuries. This is the typical ankle “sprain” where the foot and ankle turn “inwards”. Other types of ankle injuries can also damage the joint surface. This often occurs in work-related settings such as walking on uneven surfaces.

Chondral injuries can vary in size, location and also the depth of the cartilage surface involved. There may only be a partial thickness injury where the most superficial layers of cartilage cells may are involved, or the full thickness of cartilage down to the underlying bone may be affected. Symptoms vary but if the chondral injury is large enough it can lead to acute pain, swelling and stiffness. In addition if a fragment of the torn cartilage becomes loose and separates, it can be caught between the ankle joint surfaces. This can result in the ankle getting stuck or “locked” with certain activities resulting in severe pain and inability to walk. This often results in great difficulty returning to normal work duties.

Natural Progress
As the cartilage lining the ankle joint has only a very limited blood supply and little potential for regeneration in an adult, injuries to the joint surface do not generally heal well. If not appropriately treated the problem is of ongoing pain and swelling which will impede rehabilitation and fitness for work.

Investigations

Following an acute work related ankle injury, the investigations ordered depend on the clinical findings on examination of the ankle. It is reasonable to have an Xray performed to exclude any fractures but this does not actually demonstrate subtle injuries to the cartilage surface given that it is generally not mineralized and thus does not show up on an Xray. As such this may require a special MRI scan to define a cartilage injury.

Treatment

It is generally reasonable to attempt physical rehabilitation in the first instance to accelerate fitness for work. A combination of anti-inflammatory medication and bracing or strapping of the ankle can help. Physiotherapy is also useful to regain strength and movement through the ankle with specific exercises. Other modalities such as ultrasound treatment can also be beneficial. In addition cartilage injuries are often associated with inflammation of the lining of the ankle joint or “synovitis”. If this is severe a cortisone injection directly into the ankle joint may help.

While most cartilage injuries of the ankle respond to this treatment, a small proportion of patients have ongoing symptoms. This is usually due to a large full thickness injury or a fragment of loose cartilage which becomes entrapped within the joint surfaces. In such cases surgical intervention may be required. The technology now exists to perform this through arthroscopic or “keyhole” surgery. This is generally performed under a general anaesthetic with the patient asleep.

The injury to the cartilage is assessed and any loose or unstable cartilage fragments are removed to create a smooth surface. If the injury involves the full thickness of the cartilage surface and bare bone is visible, this does not have the potential to heal with normal cartilage. As such the bone is drilled to stimulate healing with a scar tissue response or fibrocartilage. While this does not fully replicate the mechanical properties of the normal hyaline cartilage lining the ankle joint, in at least 80% of patients there is a significant improvement of symptoms.

While the normal hyaline cartilage lining the ankle does not naturally regenerate in an adult, there is the potential in a select group of patients to attempt a cartilage graft. This is still an experimental procedure in which the long term success rates are as yet unknown. At this stage few patients have symptoms bad enough or meet the strict criteria to have this surgery.

Physical Rehabilitation

Arthroscopic surgery is generally performed as an inpatient case. Depending on the specific problems with the ankle most patients will have a cast or brace on the ankle following surgery and will be restricting their weight bearing with crutches. Sufficient pain relief is organized and rehabilitation commences generally in a further two weeks once the wounds have adequately healed. This primarily involves range of movement exercises and strengthening of the muscles, and a rapid return to full weight bearing. A physiotherapist can be helpful in assisting with this.

Depending on the degree of the cartilage injury and amount of surgery required, most patients are comfortably weight bearing and walking without crutches approximately two weeks following surgery. A brace may be required and at this stage fitness for work would be reasonable to consider for office based duties and some manual jobs. Physical rehabilitation increases at this stage and can include hydrotherapy and further muscle strengthening exercise. In general fitness for work for heavy manual labour can be considered between four to six weeks following surgery, when a brace is usually no longer required.

Work Restrictions
Following arthroscopic surgery, the patient should avoid prolonged standing and weight bearing for the first two weeks. Thereafter work-related activity levels can be increased and by six weeks following surgery, few work restrictions generally apply.

Prognosis

In general most patients recover well from work-related articular cartilage injuries of the ankle if they are appropriately treated. There is a theoretical concern of potential arthritic changes occurring after loss of part of the cartilage surface especially as the fibrocartilage scar that forms does not have the same mechanical properties as normal hyaline cartilage. However in general only the abnormal and torn part of the cartilage is removed leaving as much of the normal cartilage intact as possible, and the majority of patients will have a good outcome in the long term. The outcome following removal of loose cartilage is also far better than leaving a fragment locked between the joint surfaces.

Disclaimer: Please note that the information in this article is intended as only a general guide to cartilage injuries of the ankle. Every patient’s clinical situation will differ and treatment is modified depending on the specific problems and needs of each patient.

Dr. Rezah Salleh
Orthopaedic Surgeon
MBBS(UWA) FRACS
Suite 217 Saint John Of God Subiaco Clinic
25 McCourt Street
Subiaco WA 6008
Phone: (08) 9382 9102
Fax: (08)9382 9104

The normal knee contains two semicircular discs lining the joint line known as menisci. These are composed of an elastic fibrocartilage and provide the important job of “shock absorbers” thus reducing stresses through the joint and limiting abnormal wear. They also perform a secondary role in contributing to knee joint stability.

Mechanism of Injury

The knee is commonly involved in work-related injuries. The meniscus is particularly prone to a combination of flexion and rotation of the knee. This often occurs in work-related settings such as heavy load bearing.

Injuries to the meniscus generally result in tears which lead to acute pain, swelling and stiffness. In addition if a fragment of the torn meniscus is caught between the knee joint surfaces this can result in the knee getting stuck or “locked” with certain activities resulting in severe pain and inability to walk. This results in great difficulty returning to normal work duties.

Natural Progress

As there the meniscus has only a limited blood supply in an adult, there is little potential for spontaneous healing in all but small and incomplete tears. If not appropriately treated the problem is of ongoing pain and swelling which will impede rehabilitation and fitness for work.

Investigations

Following an acute work related knee injury, the investigations ordered depend on the clinical findings on examination of the knee. It is reasonable to have an Xray performed to exclude any fractures but this does not actually demonstrate a meniscus tear. As such this may require a special CT or MRI scan to show it.

Treatment

While it would be reasonable to attempt physical rehabilitation in the first instance to accelerate fitness for work, if the knee does not respond quickly to this then surgical intervention may be required. The technology now exists to perform this through arthroscopic or “keyhole” surgery. This is generally performed under a general anaesthetic with the patient asleep.

The injury to the meniscus is assessed and in a small proportion of patients a tear may be repairable. However due to the fact that the meniscus has a poor blood supply and that most tears often result in several fragments, in most cases the torn fragments need to be removed. As much of the remaining normal meniscus is left intact and is trimmed to a smooth surface.

Physical Rehabilitation

Arthroscopic surgery is generally performed as a day case. Depending on the specific problems with the knee most patients can start full weight bearing on crutches immediately following the surgery. Sufficient pain relief is organized and rehabilitation commences immediately. This primarily involves range of movement exercises and strengthening of the quadriceps muscles. A physiotherapist can be helpful in assisting with this.

In general patients are comfortably weight bearing and walking without crutches by approximately two weeks following surgery. At this stage fitness of work would be reasonable to consider for office based duties and some manual jobs. Physical rehabilitation increases at this stage and can include hydrotherapy and muscle strengthening exercise. In general fitness for work for heavy manual labour can be considered between two to four weeks following surgery.

Work Restrictions

Following arthroscopic surgery, the patient should avoid prolonged standing and walking and any twisting movements or deep flexion (such as kneeling) for the first two weeks. Thereafter work-related activity levels can be increased and by six weeks following surgery, few work restrictions generally apply.

Prognosis

In general most patients recover well from work-related meniscus injuries of the knee if they are appropriately treated. There is a theoretical concern of potential arthritic changes occurring after removal of part of the meniscus due to loss of some of the “shock absorbing” capacity. However in general only the abnormal and torn part of the meniscus is removed leaving as much of the normal meniscus intact as possible. The outcome following removal of a torn meniscus is also far better than leaving a fragment locked between the joint surfaces.

Disclaimer: Please note that the information in this article is intended as only a general guide to injuries of the meniscus. Every patient’s clinical situation will differ and treatment is modified depending on the specific problems and needs of each patient.

Dr. Rezah Salleh
Orthopaedic Surgeon
MBBS(UWA) FRACS
Suite 217 Saint John Of God Subiaco Clinic
25 McCourt Street
Subiaco WA 6008
Phone: (08) 9382 9102
Fax: (08)9382 9104

Types of contact dermatitis

Irritant Contact Dermatitis
• Acute irritant contact dermatitis is caused by strongly acidic or alkaline substances touching the skin producing a burning sensation for example where skin comes in contact with strong chemicals or wet cement.
• Chronic or cumulative type of irritant contact dermatitis often takes time to develop, and is the result of breakdown of the skin barrier, and is caused by substances which irritate and dry the skin.

Allergic Contact Dermatitis
• This is caused by a substance in contact with the skin to which it develops an allergy to. It may be delayed for several hours or days before a reaction develops. However when you become allergic to a particular substance, even a very low concentration of the substance can produce a dermatitis. This occurs much less commonly than irritant contact dermatitis.

Contact Urticaria
• This is where the skin develops an immediate allergic response to contact with a particular substance. This produces a localised hive reaction on contact with the substance. It is caused by a different mechanism to the other types of contact dermatitis. The most common is latex allergy.

Almost 3/4 of all occupational (work related) contact dermatitis is caused by irritant contact dermatitis, and 1/4 by allergic contact dermatitis. Cases of contact urticaria are rare except in the health industry.

Irritant contact dermatitis

Causes

The most common cause of irritant contact dermatitis is from constant contact with water. Other skin irritants include soaps, detergents, cleansers, shampoos, disinfectants, solvents, mineral oils, paper towels, dust, hard particles, heat , sweating and low humidity. People who have an atopic history, that is have a previous history of asthma, hayfever or eczema are several times more likely to develop irritant contact dermatitis. It is important to advise patients with this history to avoid or restrict from working in jobs where contact with irritants can occur. Also precautions should be taken in the work place to protect the skin from the beginning.

The damage to the skin by the irritants often take some time to occur, and it can take many months for the skin to recover completely. Once someone develops irritant contact dermatitis and the skin barrier is broken, certain chemicals which can produce an allergic reaction are more likely to penetrate the skin. So it is important to protect the skin before the skin barrier is broken by irritants.

Management and ongoing prevention of irritant contact dermatitis

It is important to alert and identify people with a background of eczema that they have an increased risk of irritant contact dermatitis. They can then take precautions to prevent irritants coming in contact with their skin right from the beginning of their job or career.

It is important where possible for all workers to minimize contact with irritants. This can occur through glove use, and different types of gloves are recommended for different duties. In addition, gloves should be removed or changed regularly to minimize sweating which is irritating to the skin. Protective clothing should be worn when exposure to irritants are likely in a particular job. If chemicals are spilled on to the skin or clothing, this must be thoroughly washed off, and a new set of clothing worn.

Skin care in the workplace should involve avoidance of some soaps and cleansers which are particularly harsh on the skin and substituting these with soap free washes or soap substitutes matched to the same pH as the skin. It is important to dry thoroughly after washing especially between fingers and under rings. Drying the hands with towels or air dryers is less irritating than using paper towels. After washing the hands it is important to moisturize the hands with a non perfumed moisturizer. Always rub the moisturizer into the hands well including the web spaces, and extend this to the fingers and wrists. Develop a routine for the worker, and this will aid in the recovery from the episode of irritant contact dermatitis. It is important to use an appropriately strong topical steroid to the irritant dermatitis till the problem clears completely. Once the dermatitis clears preventative measures must be taken to reduce the likelihood of the same problem recurring.

Allergic Contact Dermatitis

The development of allergic contact dermatitis varies considerably between individuals. Often it takes months or even years of contact with a particular substance, and then suddenly for reasons not well understood, a person becomes allergic to it. However once a person becomes allergic to something, a rash will develop whenever they touch or come into contact with that particular substance. The rash of allergic contact dermatitis is similar to irritant contact dermatitis, but it may occur more suddenly, and more severe sometimes even with blistering. A widespread dermatitis may develop in other areas of the body not in contact with the allergen, and this is a hypersensitivity reaction to the allergen.

The diagnosis of allergic contact dermatitis is made by patch testing, and there are many allergens that can be tested. A standard series which involves the most common allergens encountered is often used. It is important to inform the doctor who is doing the patch testing the various products and material safety sheets of the products used in the workplace.

Management and ongoing prevention of allergic contact
This is similar to that of irritant contact dermatitis. The person who is diagnosed with allergic contact dermatitis should be informed about the sources of the allergen that caused the reaction, and avoid all contact with those sources. If a person cannot work without developing the rash, then either job modification or a change of duties is recommended.

Dr. Ernest Tan
MBBS FACD
Consultant Dermatologist
Burswood Dermatology
87 Burswood Road
Victoria Park WA 6100
Australia

Tel: 618 9470 3064
Fax: 618 9470 4479