How to become an expert in Lead Poisoning - Dr Mark Burgin
13/02/23. Dr Mark Burgin considers how a solicitor can determine if they have the correct expert in a case involving lead poisoning.
Lead poisoning is one of many areas in medicine where there is no one single specialist expert. Partly this is because of the relative rarity since withdrawal of lead products and partly because there is no treatment for chronic effects. This leaves solicitors who wish to instruct an expert with a difficulty. Who can they get to write a report for claimants who have suffered lead poisoning?
The correct answer is the expert who can address the issues in the case. With lead poisoning there are many possible injuries – the acute toxic effects, long term neurological changes and possible future complications such as dementia and heart attack. The ideal expert would be able to assess each system for injuries but only GPs can assess multiple systems.
A reasonable compromise is a PI expert who can write a report on the symptoms that the claimant associates with the lead poisoning and can elicit relevant signs. The solicitor then has the responsibility of obtaining evidence to prove that these are not caused by other illnesses. This means providing the medical records, arranging recommended tests to rule out alternative diseases and specialist reports in material areas.
Acute lead exposure
There are a number of clinical patterns that are associated with acute lead exposure and the expert should consider temporal association and plausible mechanism. An acute porphyria (abdominal pain) pattern with high lead levels will usually be diagnosed by the treating toxicologist. Neuropsychological (mood changes) however are more subtle and the treating toxicologist (and claimant) may miss them initially.
Gross motor neuropathy such as wrist drop or hearing loss are not likely to be missed but minor sensory changes may well be. A claimant may have noticed that they are clumsier but often are unaware of the changes. The expert is unlikely to be able to fully describe the claimant’s acute injuries unless careful examination was made at the time of the exposure.
Acute encephalopathy is obvious with headaches, seizures, coma and death. Most people with high blood lead levels have behavioural problems although these are more noticeable to their family. The claimant can be irritable and restless and have cognitive dysfunction. History from the family can be helpful for identifying these changes as the claimant may not remember.
Kidney damage with gout, jaundice and anaemia are recognised and easily detected by blood test however are rare. The claimant is likely to have been acutely unwell and may even have been admitted to hospital. Where this clinical pattern of metabolic disruption was present at the time of the exposure the expert should expect long term changes to brain and nerve function.
Long term effects
Although the half life for lead in the blood is about 30 days the half life for lead in the bones is 30 years. This means that a claimant may have lead leaching out of the bones and other tissues after a chronic exposure for decades following withdrawal from the source. When bone turnover increases due to illness or prolonged rest the blood lead may increase again to toxic levels. X-ray fluorescence can detect these lead stores and should be considered if chronic exposure was likely.
Recovery from acute lead poisoning often appears complete with the claimant stating that they have no symptoms. Examination confirms that they are neurologically normal and whilst it is not possible to rule out subtle changes the generalist expert can state that they have recovered. Some claimants however will have persisting neurological changes and this is reasonable as lead is a potent neurotoxin and nerve cells do not regenerate. MRI brain scanning and neurophysiology should be performed to rule out non lead causes and the claimant should be reviewed by a neurologist.
Psychometric testing has been suggested as an investigation however without previous tests of memory, intelligence, processing speed, executive functioning and attention and motor skills it is unclear how to interpret abnormal findings. An alternative approach is consider disability associated with these changes where the claimant (or relative) can give a description of new functional restrictions. Change in disability would provide evidence to support further investigation and reports.
Material issues in lead poisoning
The court needs to know whether there was exposure to lead, the level of that exposure and the timescale of that exposure. Where there is a clear source of the lead and the blood tests confirm levels in the dangerous range the first two issues do not require an expert. The length of exposure may need an expert to estimate although repeated monitoring may be available to give more precise timescales. Lead is known to cause harm and the pattern of harm is well described.
The expert’s main role in these cases is to record the claimant’s symptoms and identify any ongoing signs in the same way as any other PI report. The expert can then give an opinion on whether the claimant’s symptoms are consistent with the exposure. Some lawyers will argue that specialists in each area are necessary to prove beyond reasonable doubt that the symptoms are associated. A generalist expert can say if it is likely that for instance a claimant who has symptoms temporally associated with high lead levels and a plausible explanation suffered lead poisoning.
Where the claimant appears to have suffered long term damage it is more likely to be necessary and proportionate to obtain further evidence. The studies confirm that the pattern of injury in lead poisoning is complex and subtle and multisystem. Specialist experts should only be used to resolve issues that are material to the case, have high quantum and cannot be resolved in another way.
Conclusions
Becoming an expert means being able to provide answers to the court’s questions and cannot be measured by arbitrary measures invented by lawyers. A professor in toxicological medicine may know all there is to know about the acute treatment of poisoning. They may not have the large range of skills necessary to detect subtle long-term consequences of lead poisoning despite having treated hundreds of cases with chelation. Unless the case is about treatment their vast knowledge is of little use.
The larger the number of symptoms and systems injured by an accident or exposure the more likely that the best expert will be a generalist. The reason for this is that specialists focus on one system and generalists are holistic. It is also better to have a general idea of the whole picture and then get a detailed view of one bit than have lots of detailed views. The cost of instructing all the specialists that could be required in lead poisoning would be prohibitive and against CPR1.1.
The expert in lead poisoning is likely to be a generalist with (ideally) disability analysis training. They will have read a number of references but will rely mostly on clinical skills. They should have an extensive PI background so that they can write a detailed and CPR35 compliant report. There may be many issues such as chelation therapy, neurological injury and bone storage of lead that might be important. Specialists should only be used where there is evidence to suggest that they are relevant to the case.
Doctor Mark Burgin, BM BCh (oxon) MRCGP is on the General Practitioner Specialist Register.
Dr. Burgin can be contacted on This email address is being protected from spambots. You need JavaScript enabled to view it. and 0845 331 3304 website drmarkburgin.co.uk
References
Exposure to lead; Health and Safety Executive
Mason LH, Harp JP, Han DY. (2014). Pb Neurotoxicity: Neuropsychological Effects of Lead Toxicity. BioMed Res Int.
Lead poisoning and health; World Health Organization, 2015
WHO guideline for the clinical management of exposure to lead 2021
Lead, General Information; Public Health England 2016
Toxicological Profile for Lead August 2020 National Center for Environmental Health and Agency for Toxic Substances and Disease Registry Centers for Disease Control and Prevention
Lead toxicity: a review Interdiscip Toxicol. 2015; Vol. 8(2): 55–64. Wani
Lead Poisoning (Causes, Symptoms, and Treatment) patient.info/doctor/lead-poisoning-pro
Acute lead poisoning- The severity of lead poisoning symptoms often correlates with blood levels, and at high levels the following may be seen: Abdominal pain - moderate-to-severe, usually diffuse but may be colicky. Vomiting. Encephalopathy - more common in children, characterised by seizures, mania, delirium and coma, death. Jaundice (due to hepatitis). Lethargy (due to haemolytic anaemia). Black diarrhoea.
Chronic lead poisoning - Mild abdominal pain. Constipation. Weight loss. Aggression. Antisocial behaviour. Headaches. Hearing loss. Subfertility. Foot drop - due to motor peripheral neuropathy. Wrist drop - this is a late sign. Carpal tunnel syndrome. Gout. Autonomic dysfunction
Signs of lead poisoning - There are no pathognomonic signs of lead poisoning but the following may be seen: A blue discoloration of gum margins. Mild anaemia. Behavioural abnormalities (more marked in children) - irritability, restlessness, sleeplessness. Cognitive dysfunction. Impaired fine-motor co-ordination or subtle visual-spatial impairment. Chronic distal motor neuropathy with decreased reflexes and weakness of extensor muscles in adults.
This is part of a series of articles by Dr. Mark Burgin. The opinions expressed in this article are the author's own, not those of Law Brief Publishing Ltd, and are not necessarily commensurate with general legal or medico-legal expert consensus of opinion and/or literature. Any medical content is not exhaustive but at a level for the non-medical reader to understand.
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