Case 6 A pulled calf muscle

Cheryl, aged 32, consulted Dr David in the Out of Hours service on a Saturday morning with a two-day history of a painful left calf. She was concerned as to whether it could be a DVT because she was on the oral contraceptive pill and was due to fly to Tenerife that afternoon for a holiday. She had played basket ball on the previous Tuesday evening (to which she was unaccustomed) but had not noted any injury, though she had felt generally stiff the next day.

What are the clinical features that you would consider discriminatory when assessing a possible DVT?

Dr David established that Cheryl had no past history of DVT. An aunt had had a ‘blood clot’ at some stage. Cheryl was a light smoker. On examination the left calf was tender to deep palpation, particularly in one spot. Dr David thought the calf might be a little swollen. There was moderate pitting oedema of the left ankle and a scrap of pitting oedema at the right ankle. Cheryl explained that she did get ‘water retention’ on the pill.

What would you do now?

Dr David stated that he did not think that Cheryl had a DVT but that he could not exclude it. He advised that he could send Cheryl to the hospital for tests but she was anxious not to miss her holiday. They agreed that if the calf became more painful or more swollen Cheryl would seek medical help in Tenerife.

After a few days on holiday her left leg was significantly more swollen and she attended the hospital. There was a 4 cm difference in calf circumference, her D Dimer was very raised and ultrasound demonstrated evidence of extensive thrombus in the left distal superficial and popliteal veins. Despite anticoagulation Cheryl has been told that she is at risk of developing the post phlebitic syndrome. She has brought an action against Dr David alleging that he failed to appropriately manage her condition on the Saturday and send her to hospital.

Do you think her claim will succeed?

Expert opinion

Delayed or missed diagnoses of DVTs and pulmonary emboli are common causes of actions against general practitioners. The difficulty is that lower leg swelling and pain are both relatively common findings in primary care and are usually not due to DVT.

DVT is frequently suspected in young women on the oral contraceptive pill but clearly, many women are on the pill and few get DVTs. The relative risk of having a DVT on the oral contraceptive pill is about three times that of the background population. This compares with a figure of over 20 in patients after major surgery (Chunilal et al., 2003). However, the absolute risk of DVT is low, at about 1 per 1000 per year (doubling after the age of 70). In a 32-year-old woman the incidence remains very low, whether she is taking the oral contraceptive pill or not.

In view of the fact that the clinical suspicion and diagnosis of DVT is difficult there have been various clinical prediction rules that have developed to try and increase the accuracy of diagnosis. The most widely used in hospital is probably the ‘Well’s Score’ (Wells et al., 2006). This is reproduced in Case Table 2.1.

Table 2.1 Simplified clinical model for assessment of deep vein thrombosis.*

There is necessarily an aspect of subjective clinical judgment because of the question about whether another diagnosis is more likely. However, a particular difficulty is that prospective trials have given quite different predictive values for patients with different scores. In the original study 16% of the study population had DVT and 75% of those with a score of 3 or above had DVT and only 3% of those with a score of zero or less. A meta analysis gave values of 53% (score 3 or more) and 5% (zero or less). A Dutch primary care study with an overall probability of DVT of 29% gave rather disappointing figures of 37.5% (3 or more) and still 12% for a score of zero or less. Thus the role of the Wells Score in primary care remains rather uncertain.

In practice, a general practitioner should probably gather the information that is shown to be discriminatory in the Wells Score, request a D Dimer test only if the Wells Score is zero or less (when negative D Dimer should rule the diagnosis out with a probability of DVT of only 0.3%) and otherwise refer for imaging and assessment if the Wells score is 1 or more or there is clinical suspicion and a D Dimer is unavailable.

This case illustrates several of the problems that occur quite frequently in medico-legal cases.

One issue is the question of informed consent. Dr David recorded that he ‘offered’ to send Cheryl to hospital but that she decided against it. Her decision only absolves Cheryl of liability if she was fully informed by Dr David of the consequences of her decision. To give consent in law the patient must have been told all the risks that a reasonable person would consider might influence their decision. In practice it is rare to see documented evidence of such ‘informed dissent’.

In this case it would have been necessary to tell Cheryl that there was some degree of risk that she may have a DVT and that if it was undiagnosed it could lead to death from pulmonary embolism or disability from pulmonary embolism or DVT. Cheryl argued that she would not have taken the decision to fly if she had been so informed.

The second issue is the question of measurement and documentation. Dr David recorded that the calf was ‘a little swollen’. Clearly this is a less specific bit of information than a recorded circumference taken 10 cm below the tibial tuberosity. Furthermore, since there is evidence that a difference in circumference of more than 3 cm is significant and of less is not, a general practitioner is arguably obliged to make use of that specific bit of information in a clinical situation in which diagnosis is difficult. It would be difficult to argue that Dr David’s assessment was thorough when it would have been easy to carry out the measurement, helpfully discriminatory and it is widespread practice.

A further difficulty was that history to suggest any alternative cause (a gastrocnemius strain or tear) was poor. It was not plausible that Cheryl’s symptoms starting two days later were due to an unnoticed calf strain when playing basket ball.

Cheryl’s Wells Score would probably have been 3 if Dr David had measured her calf and her probability of having a DVT was probably 30% to 60%, but certainly not insignificant.

In this case these factors would make it not possible to defend an allegation of breach of duty.

Legal comment

Cheryl’s lawyers will approach a GP for an expert report on whether Dr David was in breach of his duty to her. They will provide their expert with a written statement by Cheryl and with Dr David’s records of the consultation. The expert’s report will be based on this evidence.

In her witness statement, Cheryl will describe the consultation. She will recall the advice Dr David gave her on whether to go to Tenerife that afternoon or go to hospital for some tests. It seems that Dr David did not give her adequate advice about the risk she was taking by not going for tests, and that if he had, she would have stayed for the tests. Unless he has adequately recorded his advice about the risks she ran, Dr David will be at a significant disadvantage in the proceedings.

Thus the success of Cheryl’s litigation will turn on the facts, and whether the Judge believes her or Dr David.

In those circumstances, Dr David’s MDO is likely to wish to settle the case rather than take the risk of going to trial. After all, this may not be a very expensive case to settle – Cheryl is to be compensated for the pain and suffering which she would not otherwise have had, and that was only for a few days until she got treatment. Cheryl may be entitled to compensation if she can show that she is more likely than not to develop post-phlebitic syndrome and that this was due to Dr David’s failure to properly advise.

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