Muir v Accident Compensation Corporation

IN THE DISTRICT COURT AT WELLINGTON [2014] NZACC 31 UNDER The Accident Compensation Act 2001 IN THE MATTER OF an appeal pursuant to section 149 of the Act (Appeal No. ACR 360/11) BETWEEN ROSEMARY MUIR Appellant AND ACCIDENT COMPENSATION CORPORATION Respondent Hearing: 27 January 2014 Appearances: Appellant in person Mr C Light for respondent Judgment: 19 February 2014 RESERVED JUDGMENT OF JUDGE D A ONGLEY [1] This appeal concerns the respondent's refusal of cover for a treatment injury of dental caries resulting from alleged failure of a medical professional to warn the appellant of the level of dental care needed while using prescribed Venlaflexine. [2] The appellant was prescribed Venlaflexine from about 2005. A side effect of the medication was dry mouth, a condition known as xerostomia. She found that saliva was increase by using chewing gum. She also had a rigid jaw, a condition that was a possible side effect of medication. That was also relieved to some extent by chewing gum. [3] Eventually, the appellant was found to have dental caries caused to s significant extent by the sugar contained in chewing gum. She maintained that she should have been informed of the need for dental care and avoidance of sugar when she was prescribed Venlaflexine. Background [4] Dentist Mr John Morton wrote on 1 September 2010: "Please find enclosed all x-rays and opg scans relating to Rosemary's treatment. Most relevant of these is scan taken 4/10/07 - the date of her first visit to me. In consultation with her I outlined areas of decay and fractures in red biro - this gives best indication of the state of mouth upon initial examination. Her last dental visit prior to seeing me was 15 months previous, according to her and she was concerned at the extent of her restorative problems. For such a lot of deterioration there had to be a cause and on questioning discovered Rosemary in an effort to ease a sore jaw had taken to chewing gum - unfortunately not sugar free. It had eased jaw and dry mouth symptoms, but as was explained to her, the combination of essentially a regular sugar bath and the recognised acidic environment that comes with drug induced xerostomia, had a huge bearing on the current state of her dentition. She requested treatment options that best fitted her desire to hold on to her teeth with what she felt affordable. At her next appointment medical history and gum chewing habits were rediscussed and the first part her treatment was a guarantee to either give up gum, or at least use sugar free. We did discuss the dry mouth properties venlafaxine - but also pointed out that other factors such as chewing gum and oral hygiene were equally important and a combination of all factors was potentially disastrous and that her mouth reflected this We put her on a regime of Fluoride mouthwash and Tooth Mousse and slowly went about restoring her mouth. Ensuing scans reveal further treatment over a 3 year period. Examination and x rays 31/08/10 show current situation. Her oral hygiene is improved and her overall status is stable. She no longer chews gum and lolly consumption is down. The large number of restorations prior to 2007 would indicate that she has been prone to dental problems. I don't know how long she has been on Venlafaxine. I feel that constant use of sugary chewing gum in conjunction with dry mouth has been a major factor in her dental damage - not solely due to the medication. I do not know if loss of teeth through decay, wear, diet, care, and possible drug induced dry mouth constitute a personal injury." [5] The respondent referred the available information to dental surgeon Mr J B Tansley for advice as to whether the appellant's dental condition had been caused by Venlafaxine. He commented particularly on historic extensive dental restoration work when he reported on 20 October 2010 as follows: "From the earliest records to the present time there is a history of extensive restorative work. There were multiple fillings at each course of treatment. There are no records for the periods 1984 to 1990 or from 1992 to 1997. Whether these are simply unavailable or she did not attend a dentist in these periods is not known. The x-rays taken prior to 2005 (before she started taking Venlafaxine) show extensive restorative work plus recurrent decay and new decay. This pattern is repeated in the subsequent x-rays and includes the extraction of some teeth. Dr Morton, in his report, mentions the frequent use of chewing gum to alleviate a sore jaw. Unfortunately this was not sugar free and would be a major cause of dental decay. He comments that after discussing this with her she changed her habits and improved her oral hygiene. This comment on her oral hygiene, coupled with her extensive restorative work over the years, implied that there was room for improvement. This paints a picture of a mouth that has had high maintenance requirements from her teenage years. There appears to be gaps in regular care and, at least latterly, a high sugar intake which would be a major factor in a high decay rate, together with suboptimal oral hygiene. On the information available and on the balance of probabilities her dental state is not primarily due to the ingestion of Venlafaxine. Her current dental maintenance requirements are consistent with her historic dental maintenance requirements prior to her starting Venlafaxine. Venlafaxine can cause dry mouth in some patients and is a known side effect. To the extent that it may be a factor, it is an ordinary consequence in terms of the Act." [6] The appellant accepts that xerostomia is a normal consequence of Venlaflexine, but the claim concerns a failure to inform her of the secondary consequences of xerostomia with the need for good oral hygiene and the need to avoid excessive sugar. She says that if she had known she would have taken those precautions and her dental caries would have been avoided or reduced. Mr Tansley advised the Corporation that the appellant's poor dentition was already established before 2005 and was not caused by lack of advice. There remains a question whether her dental caries became worse than would otherwise have been the case had she not had Venlaflexine without receiving proper advice. [7] The Corporation issued its decision on 10 November 2010 refusing cover. The decision was accompanied by a treatment injury report explaining the reason for declining the claim, including a copy of Mr Tansley's report. [8] Treatment injury is defined in s 32(1) as personal injury: (b) caused by treatment; and (c) not a necessary part, or ordinary consequence, of the treatment, taking into account all the circumstances of the treatment, including - (i) the person's underlying health condition at the time of the treatment; and (ii) the clinical knowledge at the time of the treatment. [9] Under s 33(1)(d), "treatment" includes a failure to provide treatment. The focus of this claim is a failure to accompany treatment with advice about the consequence of xerostomia and neglect of dental hygiene. One approach to the appellant's case is that failure to provide advice is failure to provide treatment. [10] A literal interpretation of these sections would lead to a convoluted proposition that, because treatment includes failure to provide treatment, then treatment injury includes that which is not an ordinary consequence of failure to provide treatment. Clearly the legislature did not intend to exclude cover for injury which could be an ordinary consequence of a failure to provide proper treatment. The preferable approach is that "treatment" in s 32(1)(b) means treatment that has been properly administered. The test is whether the injury is not an ordinary consequences of properly administered treatment. [11] However the argument in the appeal did not bear on any questions of interpretation of the legislation. The respondent's case is that there is no evidence of a direct causal link between prescription of Venlafaxine, and the appellant's dental decay. The true cause was her use of sugared chewing gum. [12] Ms Muir obtained from Mr Morton another letter dated 8 April 2011 updating her dental condition. He wrote: "Rosemary had her routine dental check up 2/1 1/10 and was found to be dentally fit. Her oral hygiene is very good and there has been no resumption of previous dental problems. We put this down to her greater awareness of diet as much as anything. As discussed in previous letter to ACC - her oral hygiene has always been satisfactory and because of this fact we were unaware that there were other issues [i.e. diet and medication] at work. Sadly all my previous records are unable to be accessed since the earthquake of Feb 22nd > [13] The appellant applied for a review and attended a hearing on 11 April 2011 accompanied by a support person. The Reviewer, Mr J Greene, took account of the historic dental records, the report form Mr Morton and the opinion from Mr Tansley. He recorded Ms Muir's evidence that she had used sugared gum because she believed that there may be a risk of cancer from gum with artificial sweetener. She said that she would not have eaten sugary foods if she had known of the risk of damage to her teeth and that she stopped chewing gum as soon as she was told about the link to dental decay. That was in 2007. [14] Ms Muir explained that she had tried exercises to loosen her jaw. She had conflicting advice and a specialist whom she saw concerning hearing problems advised her against exercises that she was using to relax her jaw. Chewing gum provided some relief and that was an additional reason for using it. She said that the Venlaflexine pack simply stated "May cause sleepiness, limit alcohol". [15] The Reviewer approached the problem on the basis that "to succeed, Ms Muir must prove that there is a probable causal link between the treatment she received (in this case, the prescription of the drug Venlafaxine) and her dental caries". He noted that there was no evidence of any contraindication between Venlaflexine and eating sugary foods, but that it is clear that eating sugary foods increases the risk of dental caries, particularly in the absence of careful dental hygiene. The Reviewer found that there was no causal link between prescription of Venlaflexine and the occurrence of dental caries. Mr Morton had said that the causes were a combination of dry mouth, use of sugared gum and deficient oral hygiene. The Reviewer noted that causes of the appellant's dental decay involved decay, wear, diet, care and possible drug induced dry mouth. He did not identify a single treatment related cause. [16] After the review, the appellant obtained a referral to Dr Ajith Polonowita, specialist in oral medicine. Dr Polonowita wrote after seeing Ms Muir on 17 April 2012. This was a short letter that did not describe a causal link with Venlaflexine. The letter simply listed these conclusions: "PRESENTING COMPLAINT: 7 year history of dry mouth and 'jaw pain' RELEVANT MEDICAL HISTORY: Depression SUMMARY OF EXAMINATION: Tenderness of muscles and TMJs INVESTIGATIONS: OPG and blood tests, saliva Flow DIAGNOSIS: TMD and hyposalivation MANAGEMENT: Conservative management and occlusal splint, possible pilocarpine." [17] The point of the letter in relation to the appellant's case is that it confirms that she had dry mouth for seven years, and that she had temporomandibular jaw symptoms when examined in 2012 with reduced salivation. That confirms her reasons for using chewing gum to increase salivation and relieve jaw symptoms, but it does not take the claim further. The central question in the appellant's claim is whether medical professionals should have warned her of the need for scrupulous dental care, or should have warned her against using sugared chewing gum. The respondent on the other hand contends that this question does not need to be addressed, because treatment was not the cause of personal injury. [18] There are two further letters in evidence. The first is dated 12 February 2013 from Dr Anita Nolan, oral medicine specialist. It contains an informative summary of the appellant's relevant medical history, then discussed the dental problem, including these observations: "We discussed Mrs Muir's past history of dry mouth. In about 2005, Mrs Muir was prescribed Venlafaxine for depression. She recalls she was given a sheet explaining the side effects of Venlofaxine, including dry mouth, but had no idea of the implications and consequences of a dry mouth nor the precautions she should take to prevent dental damage. Additionally, as she was depressed at that time, she did not consider seeking any additional Information on Venlofaxine and simply accepted dry mouth as a possible adverse effect and symptom. She had some jaw problems and was advised to chew gum. Unfortunately she used a sugar containing gum, not realising the effects it would have on her dentition or that she was dentally vulnerable due to the drug related salivary hypofunction. She did not change her diet in any way. It is certainly most unfortunate that this lady seems to have had a long history of dry mouth and now has quite a damaged dentition. Mrs Muir herself is quite adamant that she is not attributing blame to any clinician, in particular her doctor. However, she feels that she was not made aware of the consequences of the medication and the impact it might have on her teeth. She accepts she had some dental canes before that she did not appreciate that the situation could be worsened as a result of salivary hypofunction." [19] Dr Nolan's letter did not give an opinion concerning the advice that should properly accompany the prescribing of Venlaflexine or any other relevant medication. If causation were shown, contrary to the respondent's position, the answer to the question whether personal injury was not an ordinary consequence of medical treatment must still depend on expert medical advice concerning the proper administration of medical treatment in the circumstances of the case. It is not a case in which a failure is self-evident or can reliably be concluded from the primary evidence. [20] Finally, the Corporation obtained advice from Dr Fiona Davies-Payne, specialist in special needs dentistry. Dr Davies-Payne obtained from the appellant a history including heavily restored dentition at an early age. On this point, Ms Muir submitted that dental practice before the 1970's often involved extensive drilling and filling, but that in fact she did not have extensive decay. After describing aspects of patient history, Dr Davies-Payne wrote: "Later she developed a 'sore jaw' and was given a mouth guard by Dr Kennedy to wear to alleviate the clenching habit and symptoms of sore jaw joints that she had developed. She attributes this to use of venlafaxine and this is mentioned in the list of side effects. Miss Muir took up chewing gum also to help the discomfort she felt from her jaw. She was not aware of the risks of chewing gum that contained sugar at the time. However, she stopped in 2010 on the advice of a dentist (Dr John Morton) who explained the risks associated with its use. She also improved her oral hygiene and stopped eating sweet foods. . . . On examination, she has a number of missing teeth, heavily restored dentition, with a number of restored cervical cavities. This pattern is often seen in association with dry mouth and clenching and grinding habit. She has little active periodontal disease in the posterior dentition but does have evidence of this condition in the upper anterior area where she has lost teeth and has a very mobile upper incisor. Saliva testing was carried out which put her in the at risk area for all categories (GC Saliva test kit) 1-5 except 2 which was normal (watery, clear saliva). She therefore suffers from a reduction in both the quality and quantity of saliva. Overall my impression is that Miss Muir had a high caries rate as a young person but that the long term use of sugar containing chewing gum and subsequent long term use of antidepressants, asthma inhalers and antihistamine will have had a significant effect in contributing to the deterioration of her dentition." [21] This letter supports the appellant's case that she had a recognisably risk of consequential decay, and that sugared gum was a contributing cause. The respondent does not dispute that sugared gum was a cause, but says that treatment was not a cause. Dr Davies-Payne mentions long term use of antidepressants as a contributing cause, but that is not a live issue in the appeal because it falls within the category of ordinary consequences. [22] What is missing, in the context of the appellant's argument, is any discussion of the question whether treating professionals had an obligation to give precautionary information and advice in the course of proper treatment. It is left to the Court to make that pronouncement without the assistance of evidence of medical standards. Submissions [23] Ms Muir presented her appeal in a very reasonable and balanced way. She supported her argument with reference to the judgment delivered in this Court in Groves [2012] NZACC 200. The appellant in that case was prescribed various tricyclic medications causing xerostomia. He used the medications over a long period of time and the Corporation received advice that the extent and severity of Mr Groves' xerostomia and dental caries was exceptional and unusually severe. There was evidence that he required "an energetic programme of clinical support". In that case I found that some degree of dental caries was an ordinary consequence of treatment with medication causing xerostomia. However the appellant's dental decay was severe and was allowed to continue untreated. I found in that case that there was a known need to avoid long term consequences and that a failure to adopt preventive measures as part of treatment was a contributing cause of dental decay. [24] The chain of causation in that case did not involve an added cause, which in this case was overuse of sugared chewing gum. Mr Groves was known to be depressed and disorganised and his dental neglect, over a period of 10 years, was obvious enough to treating professionals to require intervention as an aspect of proper treatment. That is to say that at the time of long term treatment with tricyclic anticholinergic drugs it would have been apparent to health professionals that he had a high risk of severe dental decay and he needed not only advice but some kind of active intervention. [25] The present case is different, to the degree that the effect of excessive sugared foods and inadequate dental care was not a clear and present risk at the time of treatment. There is no expert evidence in this case, as there was in Groves, that there was a professional responsibility to accompany the appellant's treatment with some level of information or intervention to prevent possible consequences of xerostomia. [26] The present case falls more obviously into the category of information and advice about side effects of medication. Ms Muir was informed that use of Venlaflexine could cause dry mouth. Her claim is that the treatment should have been accompanied by information that she should avoid sugared foods and take special care with oral hygiene. [27] The appellant submits that it should be mandatory that the patient is given a dry mouth test by their treating professional and then such advice that may be necessary to avoid the risk of dental decay. She submits that all containers of medicine that can cause xerostomia should display a warning against sugared foods and neglect of dental hygiene. [28] I agree that would be a commendable measure of precaution against the unfortunate dental effects of xerostomia, but this is not a forum with a primary purpose of making recommendations on medical and dental practice. The evidence in this appeal is confined to the particular case in terms of history and professional responsibilities. Decision [29] The question for treatment injury cover is whether the injury suffered by the claimant was a necessary part or ordinary consequence of medical treatment. Medical treatment in the context of's 32 of the Act means properly conducted medical treatment. The appellant says that dental decay was a foreseeable consequence of treatment without adequate information and advice, but was not an ordinary consequence of proper medical treatment. [30] Dr Davies-Payne took account of the appellant's high caries rate as a young person, but she was satisfied that the long term use of chewing gum containing sugar had "a significant effect in contributing to the deterioration of her dentition". In the same sentence, Dr Davies-Payne implicated the use of use of antidepressants, asthma inhalers and antihistamine. [31] There is no persuasive evidence that Venlaflexine and xerostomia would have been a significant cause of dental caries without the added complication of appellant's use of sugared chewing gum. Medical treatment with Venlaflexine was an indirect cause, in that it produced the risk of dental caries in certain circumstances. The direct cause was the use of sugared gum and that was not part of treatment. [32] It would obviously be beneficial for prescribers of Venlaflexine or medications causing xerostomia to give positive advice about the need for careful dental hygiene. At some point, the appellant suffered as a consequence of failure to receive that kind of advice, which she may have followed and avoided excessive dental caries. However the evidence is not sufficient to show that there were circumstances in which the treating professionals failed to administer proper treatment, and that dental caries would not have been an ordinary consequence of proper treatment in the circumstances, including the appellant's underlying health condition and clinical knowledge at the time of treatment. [33] The answer is not satisfactory for the appellant, who perceived a failure that caused her to take a course of action that she could have avoided with proper advice. For the foregoing reasons however, I find that the claim does not fit the criteria for cover for a treatment injury. [34] The appeal is therefore dismissed. Judge D A Ongley District Court Judge