The Case of C.O.: A Problem Based Learning Case

Emory University - Rollins School of Public Health
Atlanta, Georgia

Instructor(s): Frumkin, Howard
Subject area: Health / Medicine
Department: Public Health
Level: Undergraduate Medical
Number of participants: 18
Duration of exercise: approximately 90 minutes
Cost/equipment needed: None
Learning objective: Develop Individual Skills, Provide Information
Teaching style: In-class Activity

Please note that the copyright for this course project is retained by the instructor.



This problem based learning case is presented to third year medical students at Emory University as part of their Internal Medicine rotation. The students work through an actual case presentation of an occupational health problem. The instructor guides the discussion as the students work through the case. In an interactive question/discussion format, needed information is provided to the students to work through the differential diagnosis and arrive at the appropriate conclusion of solvent-induced neurotoxicity (the solvent consists of Varnish Makers' and Printers' (VM&P) Naphtha in mineral oil).


C.O. is a 45 year old woman who presented in December 1993 complaining of numbness of her head, headache, decreased concentration, and nervousness, developing over the past year.

She had been generally healthy until late 1992, when she developed several symptoms. These included chest pains, upper respiratory irritation with a raw, burning feeling in her chest, associated shortness of breath, dizziness, nausea, and dry, red, cracking skin on her hands. These symptoms seemed to improve on the weekends, and became worse during the weeks. She visited her local physician who recommended several days off from work; this led to relief of symptoms.

Within two or three months she had developed additional symptoms including shortness of breath at night, a sore neck, chronic headache, decreased appetite, and chronic nausea. She had difficulty getting to sleep and staying asleep, and found that she needed more pillows to sleep.

In October of 1993 her situation became much worse. She developed numbness of her arms, head, and perioral region, and frequently felt "jittery" and nervous inside. Her respiratory irritation worsened, her nausea became severe, and on several occasions her symptoms became so severe that she had difficulty working. On the first occasion after leaving work, she almost blacked out while driving home. On a subsequent occasion she noted visual changes, severe lightheadedness, and jerky muscular activity, and was unable to feel her feet touching the floor as she walked. She consulted the plant nurse, who reportedly noted very high blood pressure. This improved after a few minutes of observation. Her local physician found that her physical examination was normal except for a questionably positive Romberg sign and a depressed affect; he verified that her thyroid function was normal, treated her with Valium, and referred her for psychiatric care. The psychiatrist reportedly found no psychiatric disease, and suggested that a workplace exposure might be causing her symptoms.

The patient had been on sick leave for the six weeks prior to presentation. At the time of evaluation she stated that she was feeling much better, and that her symptoms, although persistent, were improving every day. The major persistent symptoms at the time of evaluation were headache, scalp numbness, a feeling of nervousness, and difficulty concentrating.

Past Medical History

Past medical history was remarkable for childhood asthma, hypothyroidism transiently in 1989, and a single seizure in 1984 following treatment with Danicren for endometriosis. Her surgical history included BTL in 1979, a TAH/BSO in 1983 for endometriosis, and bladder suspension in 1984. She was allergic to penicillin. Medications at the time of evaluation included estradiol, thyroid replacement, and trazodone.

Social and Personal History

The patient lived with her husband, a clerk, and their 18 year old daughter. She was a non-drinker and a non-smoker and reported no particular hobbies or activities in her spare time.

Occupational History

In 1990 the patient had started a new job at Ryobi, a tool manufacturing company in South Carolina. She worked on the assembly line for the first year, and was promoted to inspector during her second year. During her third year (in the autumn of 1992) her inspector duties were combined with duties as a cleaner. She would work at the end of an assembly line that produced belt sanders. Her task was to clean and inspect each sander as it came down the line. She accomplished this by using a mixture of VM&P naphtha in mineral oil (one part naphtha, 5 parts mineral oil). This mixture was in a one gallon jug with an open top that sat close to her work space. On top of the jug was a screen that held a perpetually soaked rag. She would reach for the rag and clean the tools with it. There was no local ventilation and no area ventilation. She described substantial inhalational exposure to this mixture. She also noted that she had had red, irritated hands early in her employment, but since commencing the use of plastic gloves, this had not been a problem.

The patient stated that coworkers at her plant who shared similar jobs also had similar symptoms.

Review of Systems

Review of systems was positive for weakness, fatigue, and loss of appetite, a variety of neurologic and psychiatric symptoms, and the other symptoms as noted above.

Physical Examination

The patient was a pleasant, cooperative woman who appeared her stated age. Her weight was 126, her BP 104/72, and her heart rate 64. General physical examination was completely normal. On neurologic examination, her mental status was alert and oriented in three spheres, her cranial nerves were normal, and her Romberg was negative. She had decreased vibration sensation diffusely, but normal sensation to pinprick and proprioception. Her strength was normal proximally and distally, and her deep tendon reflexes were strong and symmetric.

Laboratory Evaluation

A CBC and chemistry panel gave normal results.


Additional handouts are provided including (1) physical and chemical properties, exposure pathways, and toxicological information for Naphtha and Varnish Makers' and Painters' Naphtha, (2) etiological classifications of dementia, and (3) laboratory tests useful for the etiological evaluation of dementia.


This document was last modified on 06/14/2000 03:07:49 PM



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