Health Hazards of Solvents Case Studies

James E. Cone MD, MPH and Karen Packard, RDH, MS This presentation is made possible by a grant from the Association of Occupational and Environmental Clinics and the National Institute for Occupational Safety & Health.

Acknowledgements

     Elizabeth Katz, MPH, Industrial Hygienist, Occupational Health Branch, California Department of Health Services Robert Harrison, MD, MPH, UCSF Occupational Medicine Clinic Karen Packard, Health Educator Janet Delaney, Photographer Specific photo acknowledgements are listed on slides

Case 1: Auto Mechanic

 24 y.o. male  Auto Mechanic  Worked for 22 months  October 1996: fatigue  January 1997 : – Swollen hands – Numbness, tingling both hands and plantar surfaces of both feet – Spread to legs, waist and lower forearms  Photo used with permission: A. Chandrasekhar, Loyola University Other workers reported similar symptoms, less severe

Medical History

 No prior history of diabetes or thyroid disease  Alcohol: One drink per week.

Exposure History

 Auto Mechanic: Brake repair  Top worker for 10 months (# jobs/day)

Exposure History: Amount

 Used 5-10 12-oz. aerosol cans / day of same brake cleaner  Frequently sprayed on rag, latex gloves used  No local ventilation but had open garage doors, except in winter  No IH or biological monitoring in past  No hobbies with solvent exposure  Previous use of perchloroethylene mixtures

Specific Solvent

 50-60% hexane (composed of 20-80% n-hexane)  20-30% toluene  1-10% each of methyl ethyl ketone, acetone, isopropanol, methanol & mixed xylenes.

MSDS for Brake Cleaner

Physical Exam

 No skin changes  HEENT: – No nystagmus – Visual acuity normal – No loss of smell – No loss of hearing  GI: Liver size 8mm to percussion Photo used with permission: A. Chandrasekhar, Loyola University

Neurological Exam

 Marked sensory deficits with complete loss of joint position sense in lower extremities  Romberg test – positive  Abnormal tandem gait  Deep tendon reflexes absent bilaterally in all extremities Photo used with permission: A. Chandrasekhar, Loyola University

Mental Status

 Normal serial 7’s  Recalls 3 objects at 5 minutes  Digit span 10 forward, 6 reverse Photo used with permission A. Chandrasekhar, Loyola University

Diagnostic Tests, Rx, Referral

 Liver Function: AST 33 U/L (Normal 0-35 U/L), ALT 50 (Normal 0-35 U/L).  No biological monitoring was performed as he had been removed from further exposure. – What biological monitoring could have been performed if he was continuing to work with solvents?

– Nerve Conduction Tests – Abnormal, subacute progressive mixed motor sensory neuropathy with predominant distal nerve involvement    Initial Diagnosis: Guillain-Barre Syndrome Treatment: Trial of steroids Referral: Occupational Medicine Consultation

Biological Monitoring

Substance TLV Skin Abs. BEI Urine/l Hexane Toluene 50 50 Yes Yes 2,5hexanedione 5 mg/g creat.

O-cresol 0.5 ug MEK Acetone 200 500 MEK 2 mg Acetone 50 mg Methanol Xylene 200 100 Yes Methanol 15 mg Methylhippuric Acid 1.5 g/g Cr.

Isopropanol 200 Yes

Site Visit

 Large open bays  Multiple solvents present  Storage locker of old solvent products  Confirmed that other workers report similar symptoms, less severe  Management concerned, willing to stop use of n-hexane containing products

Diagnosis and Course

 Toxic Peripheral Neuropathy due to n hexane solvent exposure, likely potentiated by exposure to multiple other solvents  Course: – Removed from further exposure – Off work for 2 1/2 years – Gradual return of function – Residual numbness of lower extremities 3 years later  Reference:

n-Hexane--Related Peripheral Neuropathy Among Automotive Technicians --California, 1999 —2000

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5045a3.htm