7 no 3, 1999
Incorporating Lead Aware Times ( ISSN 1440-4966) and Lead Advisory Service News ( ISSN 1440-0561)
The journal of The LEAD (Lead Education and Abatement Design) Group Inc.
By Prof Brian L.
Gulson, Graduate School of the Environment,
Macquarie University, Sydney NSW 2109, Australia
The following speech was given by Prof. Gulson at
"Lead Poisoning: An International Conference on Prevention and Treatment",
organised and hosted by The George Foundation, and held on 8th - 10th
February, 1999 in Bangalore, India.
Introduction
Chelation is not as widespread in Australia
as in USA, especially not provocation/challenge testing. Challenge testing is rarely
carried out in Australia by "mainstream" medical professionals.
Australian College of Paediatricians has
recommended guidelines which follow the old CDC guidelines of chelation for blood lead
concentrations (PbB) >55 µg/dL (Authors: Alperstein and
Vimpani)
Standard protocols are not really in place
and there is a wide variety of treatments.
TREATMENT GROUPS
There are four main groups
of treatment subjects:
Occupational
Point Source/Accidental
Nutritional and Environmental Medicine
Petrol sniffing in Aboriginals
Occupational
Patients are usually male adults
PbB (Lead in blood) is the exposure measure
Occupational Health and Safety guidelines
are for removal from exposure at PbB>50 µg/dL [micrograms per decilitre]
Smelter workers / miners
Pb paint removalists from structures
Firearm instructors
Number of subjects chelated per year usually
in the 10s (K. Wooller, pers. comm. 1999)
Point Source/Accidental
Patients are mostly adults and young
children
Children from smelter communities (e.g. Port
Pirie, Mount Isa); chelation may be undertaken at a PbB >50 µg/dL
Children from mining communities (e.g.
Broken Hill, Mount Isa); chelation may be undertaken at a PbB >50 µg/dL
Home renovators / pica in children. If
asymptomatic, mainstream doctors may recommend removal from exposure (G.
Duggin, pers.
comm., 1999). Otherwise chelation may be undertaken if PbB >55 µg/dL
Swallowing of objects such as lead sinkers;
PbB may be >100 µg/dL, especially if the object is not passed
One case of consumption of Kombucha tea,
prepared in a ceramic vessel; PbB >100 µg/dL.
Nutritional and
Environmental Medical Practitioners
Patients are usually adults but in the past
few years there have been an increasing number of children as young as 6 years undergoing
chelation
"Diagnosed" with metal toxicity
(based on hair analysis) often followed up with an EDTA challenge test
Practitioners suggest that several
conditions may be treated with chelation including: ischemic heart disease, chronic
fatigue syndrome, Parkinsons disease and Alzheimers disease
More than 10,000 treatments over 8 years in
one clinic; compare with occupational treatments of 10s per annum.
Two "Camps"
Doctors who chelate at >50 µg/dL (or 60
or 70 µg/dL), or not at all if asymptomatic (but with children, if PbB >55 µg/dL, are
usually chelated)
Nutritional & Environmental Medicine
(NEM) doctors who chelate at any level (10+ µg/dL). Often no PbB is taken because of
concern over the relatively short half-life of lead in blood.
Chelating Agents
CaEDTA (+/- BAL) still used in some cases
(Infuse 1g 12 h, repeat 48 h, 5d; NEM doctors follow international protocol)
DMSA (Succimer) most common now - if
available!! (problems with supply from local agent)
NEM clinics, EDTA Intravenous infusion
(commonly 6 treatments), then oral DMSA
Concerns
EDTA
depletion of essential metals (Zn, Cu, Fe)
mobilisation Pb from bone to brain (?no
longer valid - Lasman et al. 1997 SOT)
inconvenience
cost
2. Succimer
none of the above
Petrol Sniffers
Patients are mostly adolescents but can be
up to 30 years old
Major problem still amongst Aboriginal
communities especially in outback areas in Central Australia
Over the period 1991-94 there were 70
admissions to the Darwin Hospital and 7 deaths
Leaded petrol is still widely used
especially outside of major cities
Numbers hospitalised are decreasing with
introduction of unleaded petrol and AVGAS (high Pb but causes severe headaches and stomach
cramps)
Cases flown to Darwin in the period
1991-1992. Symptoms - some unconscious and severely ill with encephalopathy - ataxia,
hyperreflexia, coarse tremor, frontal lobe signs (positive palmomental reflex);
seizures common (e.g. 70% in one group)
PbB ranged from 85-115 µg/dL (n=24)
EDTA + BAL treatment in the past; Succimer
has been successfully used recently
Prechelation (day 0) mean 100 µg/dL
Postchelation (day 20) mean 40
Regained consciousness within 1 or 2 days of
treatment (cf >1 week if unchelated)
Observed faster neurological recovery but no
controlled trial has been undertaken to verify this effect
Little or no success with EDTA + BAL
treatment for petrol sniffers in Perth, Western Australia.
Special Thanks to:
The George Foundation (Fairfield, New
Jersey, USA and Bangalore, India)
Drs. Bart Currie and Chris Burns - Royal
Darwin Hospital.
Elizabeth OBrien - The LEAD Group
(Sydney)
Dr. Garth Alperstein and Prof. Geoffrey
Duggin - Royal Prince Alfred Hospital (Sydney)
Dr. Emmanuel Varipatis - Omnicare Clinic
(Sydney)
Prof. D. Thomas - Women and Childrens
Hospital (Adelaide)
Dr. Tristan Pawsey - Flinders Medical Centre
(Adelaide)
Dr. Kelvin Wooller WorkCover
Authority NSW (Sydney)g
Check out all the Indian Lead
Conference information at www.leadpoison.net
including:-
"Why Measure Pb Deposition Rates Over
Short Time Periods?" and "Identifying the Source of Lead Poisoning in Each
Individual Case" (August 9, 1999) by Mike van Alphen. Like Professor
Gulson, Mike is
a member of The LEAD Groups Technical Advisory Board who spoke at the Indian Lead
Conference.
The 440 page book of the conference
proceedings is available by sending US$20 to The George Foundation, 2 Penny Lane, Boonton
Township, New Jersey, USA 07005.