Malingering and Chronic Low Back Pain
Dr Brian P. Davies FRACS
Chronic low back pain is defined as lumbar backache with or without leg symptoms lasting over three months.
The cases that I am considering in this paper are those that are related to work injury and do not improve despite the usual methods of treatment, and some of these will be due to malingering. Malingering in the scientific literature is thought to be uncommon, but I suggest it may be more common than we think.
A few observations which might indicate why malingering is not considered to be a common event:
One of the first factors is the training of doctors and other health professionals. They believe the patient and find it difficult to accept that the patient may not be truthful. Doctors have been trained to take a history, accepting the patient’s symptoms on face value, examine the patient and to do appropriate tests including x-rays and scans and to make a diagnosis and then to advise treatment. When the patients aren’t relieved of their symptoms the doctor often blames himself and inevitably tries further investigations and other forms of treatment and referral to other specialists, all of which often produce no improvement.
I expect a Barrister taking a brief also accepts the honesty of his client and would have the same difficulties.
When people continue to have symptoms, others get involved. Some of the people who might get involved are: Physiotherapists, Masseurs, Naturopaths, Orthopaedic Surgeons, Neurosurgeons, Rehabilitation Specialists, Pain Management Experts, Psychologists, Psychiatrists, Anaesthetists, Gymnasiums, Hydrotherapy, Medication, Drugs of Addiction and there are many more.
We call it the orthopaedic merry-go-round, all believing the patient and extracting some money from the Insurers, all claiming to have a cure, but in the end nothing helps.
Costs of medical treatment for chronic low back pain in Sweden in 1996 was $2436 million, which includes the direct costs of treatment and the indirect costs due to loss of work.
Things would be different if it were known that some of these patients are malingerers.
It would be inconceivable for a doctor or anyone else to treat a patient and receive payment when the patient was known to be a malingerer, so I suggest that it doesn’t suit health professionals to consider malingering.
When I speak to my colleagues, we have all had one or two patients who have turned out to be a malingerer. The doctor has seen them behave normally, in this case perhaps bending the back, doing some heavy gardening, at the market or a chance meeting in the street. The doctor says to himself, if I’d known what I know now, I would never had treated them. Of course when eye contact occurs between doctor and patient, the patient is never seen again.
Why should malingering be uncommon, given that deception is a normal part of adult life? Such as: ‘I am sorry I couldn’t make it, I was sick’; ‘I was caught in the traffic and was late’; ‘I’ve got a headache and won’t be able to meet you’; only little fibs but that’s the way we behave from about the age of 5 years.
Orthopaedic Surgeons approach patients with low back pain by excluding all known important physical causes of backache.
This list shows some of the causes of chronic backache, excluding cancer and infection, childhood causes of backache and abdominal causes of backache.
Such causes include: -
- Lumbar disc degeneration
- Spinal canal stenosis,
- Lumbar disc prolapse,
- Stress fractures,
- Foraminal stenosis and others.
Each of these orthopaedic conditions have definite symptoms and signs, and feature on examination and typical x-ray or scan findings.
I will use the example of a lumbar disc prolapse at L5/S1, typically, following a lifting injury. The worker develops acute low back pain and often the next day the pain radiates into, say the left buttock, down the back of the thigh and calf into the outer side of the foot and outer three toes, and can be associated with numbness and tingling. The examination shows a scoliosis or twist in the spine, tenderness half an inch from the midline at the L5/S1 level on the left side, impaired spinal flexion, lateral flexion and rotation and a positive straight leg raising test, and sensory loss and motor weakness. The ankle jerk which corresponds to the S1 nerve root may be absent.
The diagnosis of L5/S1 disc prolapse is made clinically and confirmed by a CT scan or MRI scan. At this point, the scan confirms the diagnosis that you have already made; it does not make the diagnosis. It is a mistake to place too much importance on the scan.
By way of illustration, Boden has shown in the cervical and lumbar spines significant radiological abnormalities, such as disc degeneration, herniated disc, and foraminal stenosis. This is seen in 25 per cent of cases under the age of 40 years and a much higher percentage in older patients. These patients have no pain at all. That’s the important point, that the patient can have no symptoms even though they have a bad x-ray picture.
Boden concludes that the prevalence of abnormal MRI scans in the lumbar and cervical spine is common in patients with no symptoms and emphasises the danger of basing operative decisions on diagnostic tests without precisely matching the findings with the symptoms and clinical signs. The non-thinking doctor, and there are plenty around, attributes the patient’s problem of back pain to be due to an x-ray abnormality.
I have found the legal profession to be obsessed with x-ray findings rather than the clinical judgment of the doctor. They seem to consider that the x-ray is the gold standard, which can never be challenged, whereas the doctor can be challenged, and is.
Before proceeding, a few comments about that word “Pain” must be made, as it relates to malingered pain related disability in the lumbar spine. Pain is a word used to describe various unpleasant sensations. It can be nociceptive, where there is a physical cause for the pain with stimulation of the c fibres as found in the capsules of; annulus of discs, muscles and tendons. Pain may be neurogenic due to pressure or chemical affects on a peripheral nerve root and pain may be psychogenic. Nociceptive pain results from stimulation of free nerve endings interpreted in the central nervous system as pain. In the transmission from acute pain to chronic pain and disability, other factors play a part. They may be due to job loss, financial constraints or loss of social contact. If the patient’s responses to these are poor, it may lead overwhelming pain and negative impact on life, increased stress, depression, anxiety, anger, distrust with somatisation with increased pain.
Neurogenic pain results from injury in the peripheral nervous system and we could use for example, shingles.
Pain sensitivity is influenced by psychosocial factors. Ethnic and cultural influences may be important. The presence of a psychiatric disorder, such as depression, anxiety or personality disorder, typically increases pain intensity. Cognitive factors, in which the patient’s appraisal of whether a stimulus is harmful or not and the patient’s belief about the nature of the pain, are also important. Social factors such as culture, family and social support, social class, job satisfaction, education, work relations, unemployment, retirement, workers compensation, litigation, all impact on pain and disability.
The important point is that enhanced pain and exaggeration of symptoms due to psychosocial factors is common and is not related to malingering.
It is not surprising that, when we consider the pathophysiology of spinal pain is not entirely understood, that efforts to detect malingering can be difficult. Financial incentive, shown to influence back pain and malingering to obtain narcotic drugs, also complicates the picture. Detection of malingering is therefore important, both from an economic and patient care standpoint.
Malingered pain related disability, (MPRD), is the intentional exaggeration or fabrication of cognitive, emotional, behavioural and physical dysfunction attributed to pain for the purpose of obtaining financial gain, to avoid work or to obtain drugs. You will notice that the physical back condition can be enhanced by exaggeration of pain and suffering to gain greater financial rewards.
Malingered pain related disability in chronic low back pain can be identified by: -
- Substantive external incentive
- Definitive evidence of intent
- Behaviour meeting definitive intent not fully accounted for by psychiatric, neurological or development factors.
The primary question to be addressed: is the disability presentation meaningfully inconsistent?
Consistency is evaluated by three types of comparisons: -
- Within the subject
- Between the subject
- Within the subject over time.
Firstly, within the subject, the disability presentation is compared with functioning of known physiological and anatomical mechanisms. This might include signs such as the Wardell signs and effort tests. Between the subject compares the disability presentation with the capacity of persons with known pathology of comparable type and severity. Let us go back to the prolapsed intervertebral disc. We know that 90 per cent of these problems resolve over a period of weeks and perhaps 10 per cent don’t resolve and come to operation. In this respect, I might mention that the happiest patients I’ve ever had over the years have been those who have been relieved of their pain following a satisfactory discectomy.
There is nothing more disappointing to a surgeon than to operate on a patient for a work related disability, remove a huge disc, and then to see the patient not get better. There certainly is a strong contrast between the private patient and the patient with worker’s compensation in many cases.
The third comparison is within the subject across time.
The disability presentation is compared with their own behaviour when they do not know they are being observed. For example, you may see a patient coming into your consultation room and walking normally, but when you examine the patient lying on the couch, they are unable to dorsi-flex or plantar flex the ankle which is difficult to understand. The ultimate of course is that a video surveillance will often show the patient able to do many more things than they could do in the consulting room, but it is up to the doctor and the specialist to observe over the period of half an hour or so that you have inconsistencies.
Let us now go back to our typical disability patient with chronic low back pain. In the history, there are certain signs which alert you to possible problems and possible malingering.
The patient relates that the employers are no good. They are harassed. The machine was faulty. I told them to fix it. People were sacked and I had to work harder.
It’s important to get the precise details of the injury. Was it a significant injury or not? Many people will tell you that they had a fall at work but very often when you go into it, they actually haven’t had a fall, but almost fell.
Other warning signs might include the constant nature of their symptoms. Orthopaedic complaints are intermittent, but when you see patients who have pain at a serious level night and day when it’s not related to posture and the symptoms have been present for years and all methods of treatment fail, alert signs develop.
On examination, you note that the patient can walk, dress and undress satisfactorily and there is no muscle wastage. However, when examined, there is no movement in the lumbar spine and you start to wonder how this could be when the patient has actually driven in by car or at least sat in a car. The patient might show severe pain in the back over a wide area on minute pressure. This is not associated with any known pathology. There can be inconsistencies in that the patient can bend and put on their socks easily but can’t bend in the standing position.
In evaluating back pain, the straight leg raising test or its variants are considered important. This is a test for nerve root compression. The test is done by lifting the leg straight off the couch and the patient in the typical case, gets pain radiating down the leg, which is worsened by stretching the sciatic nerve by dorsiflexion of the foot. It is possible to confuse the patient when carrying out this test. For example, most patients who are malingering know about this test and as soon as one attempts to carry it out they complain of severe pain radiating down the leg. However, the test can be done in a different way. One can sit the patient on the couch with the knees bent and tell them that you are going to test the knee reflexes and at the same time you extend the leg so that you are really doing the nerve compression test. The patient doesn’t complain. It is inconsistent with the behaviour of a few minutes before – inconsistent over time.
Other features on examination which would alert the Practitioner would be the absence of definite neurological signs or signs which have no anatomical bearing, such as complete sensory loss in the whole of one leg.
After the history and examination, the initial wake up call is compelling inconsistency in the history and examination, and I would emphasise once again that the MRI scans and CT scans are not important.
To summarise things, three stages are gone through:
1. The within subject inconsistency:
Is the subject’s presentation consistent with known physiological and anatomical pathways?
2. Between subject comparisons:
The subject’s presentation is compared with patients with known pathology of similar severity.
3. Within the subject over time:
The patient’s behaviour is observed over the time of the interview when subjected to different tests. Surveillance is an example of the patient’s behaviour over time and is often the only way of detecting malingering for certain.
Malingered pain related disability of the back is, I believe, commoner than believed.
The diagnosis is reached by: -
- Exclusion of known orthopaedic conditions.
- Compelling inconsistency in the history and examination.
- Observation of the patient during examination when subjected to tests designed to expose fabrication over the time of the interview.
- Video surveillance.
- A knowledge of the complex types of pain associated with back disorders.
Clinical testing for malingering is developing and it is important, so that health dollars can be directed to areas of true need. I am a caring doctor and not someone wanting to come down on many people who are disadvantaged. I am seeking ways of detecting those few people who are rorting the system.
Figure 2: Madrid-Barajas Airport Study
Pulmonary Embolism after Air Travel
Copyright 2007. Greek/Australian International Legal and Medical Conference.
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