The Case of P.F.: 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 occupational asthma. The agent of concern is toluene di-isocyanate. The case emphasizes when, how, and the need to take an occupational history; how to get information on a patient's workplace exposures; basics of occupational asthma (agents, mechanisms, diagnosis, prognosis, treatment, and prevention); and the basics of disability insurance and workers' compensation.


P.F. is a 47-year-old man who presented in August, 1996, complaining of cough, shortness of breath, and other respiratory symptoms, gradually worsening over the last three years.

He had been generally healthy until late 1993, when he developed wheezing, cough, and shortness of breath. These symptoms would occasionally occur during the day, but more typically they would occur during the evening, sometimes when he was out, but usually when he was at home, either resting or working in his yard. The symptoms seemed to be minimal on Sundays and Mondays, but could occur on any other day. He consulted an allergist in the spring of 1994, but this evaluation was negative. In August 1994, he consulted a pulmonologist, who found normal pulmonary function. His symptoms persisted.

In July 1995, he took a vacation for the first time since his symptoms began, spending one week in Florida. He noted that his symptoms improved somewhat. Since then, his symptoms had returned to their usual level, and had even worsened toward the time he came for evaluation.

What further history would you like now?

Past medical history is remarkable for severe hypertension and cardiomegaly diagnosed in 1983, left leg pain and weakness developing in 1990 and attributed to spinal stenosis, and renal artery stenosis diagnosed in 1990 and treated with angioplasty. Medications included Tenex (guanfacine) 2 mg daily, Calan (verapamil) 80 mg TID, Lasix (furosemide) 40 mg daily, and Zantac (ranitidine) 150 mg daily. His only reported allergy was to enalapril, which had caused itching. Specifically, there was no history of hay fever, eczema, or rhinitis.

The patient lived with his wife and two of his three children, an 18-year-old son and a 16-year-old daughter. His 20-year-old daughter had recently married and moved out of the house. He had smoked a half pack of cigarettes daily from 1967 until he quit in 1994, for a total of 14 pack-years. He was a non-drinker.

The family house is s 1960's-era split level in a subdivision in Lawrenceville. The family has two dogs, which they have had for approximately 10 years. P.F.'s hobbies include lawn work, working on cars, and collecting model soldiers.

Family history was remarkable for hypertension, strokes, and heart disease in several relatives. There was no family history of respiratory disease.

What further history would you like now?

P.F.'s occupational history was as follows.

He had graduated high school at age 18, in 1967.

From 1967 to 1970, he had served in the U.S. Army as a helicopter mechanic, serving in Germany for one year and in Vietnam for 18 months. He had worked around aviation fuel, various solvents, and welding fumes, but had never experienced any adverse reactions.

From 1970 to 1976, he had worked as an automobile mechanic in Marietta. He had worked around gasoline and various solvents, but had never experienced any adverse reactions.

From 1976 to 1991, he had worked in a refractory ceramics fiber plant in Augusta. For the first seven years he operated a furnace, where a slurry was baked into bricks and other finished products. For the last eight years he worked in the shipping department, where he was responsible for loading finished products onto palettes, wrapping and packaging them, and loading them onto trucks and train cars using a forklift.

In 1991, he began work at a foam cushion manufacturing plant outside Atlanta. This plant manufactures polyurethane foam for use in automobile seats and dashboards, furniture, and other applications. The process involves the polymerization of urethane, using toluene di-isocyanate (TDI) as a curing agent. P.F.'s job is "feedstock supply man." In this capacity he monitors feed tanks to be sure enough of the components are being supplied to the process, transports and loads the components, and monitors supplies on hand in the plant. He states that a respiratory protection program is in place at the plant, and he thinks he was once instructed in how to use a respirator, but he does not use the respirator since it is very hot and uncomfortable, and "nobody can stand those things."

What further information would you like?

Physical examination revealed a pleasant man who appeared his stated age. His height was 5'6", his weight was 180 lbs., his blood pressure was 140/80, and his pulse was 68. Examination of his head, ears, eyes, nose and throat revealed no hypertensive changes in his eye grounds and poor dentition. His chest was clear. The PMI was at the fifth intercostal space on the midclavicular line, and there was a 3/6 systolic ejection murmur heard best along the left sternal border, radiating to the aortic and mitral areas, and diminishing with Valsalva maneuver. Abdominal, genital, and rectal examinations were normal. No skin lesions were noted, the extremities had full range of motion without clubbing, cyanosis, or edema, and the neurologic examination was normal.

Pulmonary function tests results were as follows:
.
TestObservedPredicted% Predicted
TLC4.42 L5.26 L84%
VC2.92 L3.55 L82%
ERV0.46 L1.15 L40%
FRC1.96 L2.94 L67%
RV1.50 L1.79 L84%
FVC2.92 L3.55 L82%
FEF 25-753.09 L/sec1.72 L/sec179%
FEV12.50 L2.34 L107%
FEV1/FVC86%..
MVV66 L/min102 L/min65%

.
Methacholine challenge revealed the following:
.
TestPretestSaline% .075 mg/ml% 0.15 mg/ml%
FVC2.922.82-32.76-62.68-8
FEV12.502.4802.20-121.92-23
FEV1/FVC86%88%80%72%
FEF 25-753.092.98-42.56-172.20-29

.

What would you like to know next?

Would you like any other tests?
What are your diagnoses?
What treatment would you initiate?
What recommendations would you make to the patient?


Summary Points

1. The need to take an occupational history, and when and how to do it.
2. How to get further information on a patient's workplace exposures.
3. The basics of occupational asthma.
  • sative agents
  • mechanisms
  • diagnosis
  • prognosis
  • treatment
  • prevention
    4. The basics of disability insurance and workers' compensation.

    (The Materials Safety Data Sheet (MSDS) for toluene di-isocyanate is included as a handout)







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



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