The Case of R.R.: 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 agents of concern are cleaning solvents, including trichlorethylene, toluene, and Stoddard solvent. The case emphasizes the differential diagnosis and evaluation of dementia; health effects of solvents; workplace and environmental exposures; taking an occupational history; and the physicians role in rehabilitation, job placement, impairment and disability rating, and workers' compensation.


Chief Complaint

R.R. is a 46-year-old man who presents with a five-year history of gradually increasing memory loss, irritability, and fatigue. He also notes a sense of loss of energy, and frequent headaches.

History of the Present Illness

He had been generally healthy until five years ago, when he started to notice the gradual onset of memory loss. Although he had lived in Waycross for his whole life, he would find himself getting lost when running an errand in town. Sometimes he would make his morning cup of coffee, forget that he had made it, and make another. On several occasions he met old friends at a store or in church, and could not remember their names. He had some difficulty remembering numbers at work, but learned to make lists or notes to himself, and was able to function satisfactorily.

After one or two years he found himself more reluctant to go out, since "I was afraid I would see a friend and forget his name." He had previously been a once-a-week bowler and a weekend fisherman, but he gradually gave these activities up. Currently he spends his spare time sitting around the house, sometimes watching television. He states, "But sometimes it's even hard to concentrate on a t.v. show."

His wife, who accompanies him to the office, confirms these complaints. She states that he is more irritable than ever; sometimes he "blows up" over little things. On questioning he admits to several heated arguments at work over the last two years. He states that he has not been involved in any physical altercations. He states that he does not enjoy playing with his grandchildren as he used to, since he finds the commotion annoying.

Past Medical History
.
Medical:Hypertension diagnosed at age 37.
Peptic ulcer disease diagnosed at age 24, treated at the time with antacids, without recurrence.
"Mild hepatitis" diagnosed at age 36 and 38 on routine physicals.
Surgical:Foot fracture at age 28 (workplace injury).
Nose and cheek fracture at age 32 (MVA).
Psychiatric:Nil.
Medications:Dyazide 2 tabs daily.
Allergies: Penicillin (leads to rash).

.
Social and Personal History

The patient is a lifelong resident of Waycross. He lives in a small house with his wife and youngest son, 22. His 24-year-old son is in the Army in Germany, and his 27-year-old daughter, who is married with two small children, lives in Brunswick. Other than bowling and fishing, his only other recreation is hunting. He used to practice shooting at a local firing range once every week or two, and go hunting several times per year, but he gave this up about three years ago.

R.R. is a non-drinker, and smoked one pack of cigarettes daily from the age of 17 until the age of 24.

Occupational History

Age 18: Graduated high school.

Age 18-20: U.S. Navy. Served as an aircraft mechanic's assistant. Exposed to aircraft fuel, solvents. No adverse effects.

Age 20-46: Machinist at CSX Railroad repair facility in Waycross. This is a large facility where locomotives and rail cars are repaired and serviced. For the first 20 years of his employment he worked at disassembling and rebuilding locomotive engines. He would often work in a pit under the locomotives. He would have to clean grease and dirt from the engines using spray solvents, remove and disassemble the engines, clean small parts in a vapor degreaser, and rebuild and reinstall the engines. He describes extensive exposure to solvents, especially in the spraying operation, since the solvent fumes would accumulate in the pit where he worked. He states that the solvents used included trichlorethylene, toluene, and Stoddard solvent. For the last seven years he has worked in the rail car repair facility, with only minimal solvent exposure.

Physical examination

R.R. is a pleasant, cooperative gentleman appearing his stated age. His blood pressure is 142/88 and his pulse is 70. Examination of his eyes, ears, nose, and throat is normal except for mild arteriolar narrowing. His chest is clear, the cardiac examination is normal, and the abdominal examination is normal. There is a suggestion of a left inguinal hernia, and the genital and rectal examinations are otherwise normal. The extremities have full range of motion without clubbing, cyanosis, or edema. The skin is normal except for moderate actinic keratosis.

On neurological examination the patient is alert and oriented. From time to time he takes a long pause while attempting to find a word, and stumbles when given problems; he becomes easily frustrated in these situations. On serial 7's he offers "100, 93, 85, 77, 70." He explains "A bird in the hand is worth two in the bush" by saying "You know... (long pause)... It's good to have something because... people might take it from you." Cranial nerves II through XII are tested and are intact. Strength is 5/5 proximally and distally, and sensation is intact to pinprick, light touch, vibration, and proprioception. Gait is normal and heel-to-shin testing is normal, but a Romberg test is equivocal. The deep tendon reflexes are ++ in the upper extremities and + in the lower extremities, and are symmetric.

A CLASSIFICATION OF DEMENTIA BY ETIOLOGY

I. DEMENTIA AS THE ONLY MANIFESTATION OF ILLNESS

"Primary degenerative dementia" or Alzheimer's Disease

II. DEMENTIA IN THE SETTING OF NEUROLOGICAL DISEASE

A. Invariably associated with other neurologic signs
1. Huntington's Disease
2. Parkinson's Disease
3. Normal pressure hydrocephalus
4. Rare degenerative diseases

B. Often associated with other neurological signs
1. Cerebral arteriosclerosis ("multi-infarct dementia")
2. Brain tumor
3. Brain trauma (e.g. cerebral contusion, chronic subdural hematoma)

III. DEMENTIA IN THE SETTING OF MEDICAL CONDITIONS

A. Arthritis (e.g. lupus)

B. Hypothyroidism

C. Cushing's Disease

D. Nutritional deficiency states (e.g. pellagra, Wernicke-Korsakoff syndrome, subacute combined degeneration of the spinal cord and brain [vitamin B12 deficiency])

E. Neurosyphilis

F. HIV

G. Hepatolenticular degeneration

H. Toxicity (bromidism, chronic barbiturate intoxication, carbon disulfide, trichlorethylene, perchlorethylene, toluene, lead, mercury)

IV. DEMENTIA IN THE SETTING OF PSYCHIATRIC ILLNESS

A. Depression (pseudodementia)


THE MINI-MENTAL STATUS EXAMINATION

ORIENTATION

1. Ask for year, season, date, day, month. Then ask specifically for parts omitted. One point for each correct answer. (0-5)
2. Ask in turn for name of state, county, town, hospital or place, floor or street. One point for each correct answer. (0-5)

REGISTRATION

Ask the patient if you may test his memory. Then say the names of three unrelated objects, clearly and slowly, about 1 second for each. After you have said all three, ask him to repeat them. This first repetition determines his score (0-3), but keep saying them until he can say all three, up to six trials. If he does not eventually learn all three, recall cannot be meaningfully tested.

ATTENTION AND CALCULATION

Ask the patient to begin with 100 and count backwards by 7s. Stop after five correct subtractions (93, 86, 79, 72, 65). Score one point for each correct answer. If the patient cannot or will not perform this task, ask him to spell the word "world" backwards. The score is the number of letters in correct order, e.g. dlrow = 5, dlrwo = 3. (0-5)

RECALL

Ask the patient if he can recall the three words you previously asked him to remember. Score 0-3.

LANGUAGE

Naming: Show the patient a wristwatch and ask him what it is. Repeat for pencil. Score 0-2.
Repetition: Ask the patient to repeat this phrase after you: "No ifs, ands or buts." Allow only one trial. Score 0 or 1.
Three-stage command: "Take a piece of paper in your right hand, fold it in half, and put it on the floor." Give the patient a piece of blank paper and repeat the command. Score 1 point for each part correctly executed. (0-3)
Reading: On a blank piece of paper, print the sentence "Close your eyes." in letters large enough for the patient to see clearly. Ask him to read it and do what it says. Score 1 point only if he actually closes his eyes. (0-1)
Writing: Give the patient a blank piece of paper and ask him to write a sentence for you. Do not dictate a sentence; it is to be written spontaneously. It must contain a subject and verb and be sensible. Correct grammar and punctuation are not necessary. (0-1)
Copying: On a clean piece of paper, draw intersecting pentagons, each side about 1 inch, and ask the patient to copy it exactly as it is. All 10 angles must be present and 2 must intersect to score 1 point. Tremor and rotation are ignored. (0-1)

Estimate the patient's level of sensorium along a continuum, from alert to coma.

Total possible score is 30 points. Patients with totals of 20 points or less usually have either dementia, delirium, schizophrenia, or a major affective disorder (pseudodementia).


FROM: Folstein MF, Folstein SE, McHugh PR. "Mini-mental state:" a practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 1975;12:189.


LABORATORY TESTS USEFUL IN EVALUATING DEMENTIA

BLOOD TESTSElectroencephalogram -- Helps confirm cerebral disturbance; if negative, suggests nonorganic diagnosis such as depression.
CT scan -- Abscesses, tumors, subdural hematoma, hydrocephalus. May show atrophy.
Lumbar puncture -- Confirms neurosyphilis, identifies other chronic meningoencephalitis.

THE HEALTH EFFECTS OF ORGANIC SOLVENTS

I. Nervous system

A.Peripheral nerves (especially n-hexane, methyl-n-butyl ketone, carbon disulfide): demyelinating axonal neuropathy
B. Central nervous system:
1. Acute
a. Mild (acute intoxication)
b. Severe (acute encephalopathy)
2. Chronic
a. Mild (changes in affect and concentration)
b. Moderate (some loss of neurobehavioral performance)
c. Severe (severe loss of intellectual function)

II. Kidneys

A. Acute: acute tubular necrosis and possible acute renal failure (many halogenated hydrocarbons such as carbon tetrachloride, petroleum distillates, ethylene glycol, and others)
B. Chronic:
1. Glomerulonephritis
2. Tubular and glomerular dysfunction

III. Liver

A. Halogenated hydrocarbons are well recognized hepatotoxins
B. Most nonhalogenated solvents are not hepatotoxic

IV. Skin

A. Contact dermatitis with scaling, dryness, and fissuring, especially of the hands
B. Mucus membrane irritation

V. Reproductive effects

VI. Pulmonary

VII. Carcinogenicity


LEARNING POINTS

1. The differential diagnosis of dementia.

2. Learning about workplace or environmental exposures, and the need to quantify them.3. The evaluation of dementia, including mini-mental status exam and neurobehavioral testing.

4. The health effects of solvents.

5. The physician's role in rehabilitation, job placement, impairment and disability rating, and worker's compensation.


DISCUSSION POINTS

Discussion of the differential diagnosis:

Review the differential diagnosis of dementia (handout).

The role of possible head injury in the MVA at age 32.

The role of possible depression.

The role of lead toxicity from firing ranges.

Review the occupational history, and the need for detailed exposure information. The magnitude of his solvent exposure can be estimated by such questions as:

Did he ever feel faint or pass out?

Did co-workers experience similar symptoms?

Did he wear personal protective equipment?

OSHA inspections? Company inspections?

What about his history of hepatitis at age 36 and 38? Could this have been a chemical hepatitis from solvent exposure?

How to learn which solvents he was exposed to, and what is known about their health effects:

Review MSDS's.

Look up solvents in a standard medical or toxicological reference, or use Medline.

How to evaluate a patient with dementia or other cognitive symptoms:

Mini-mental status exam

Neurobehavioral testing

The importance of looking for depression in patients who present with cognitive complaints:Important questions to ask:An additional handout showing the chemical structure of organic solvents is included.



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


This resource was acquired by CEEM (Consortium for Environmental Education in Medicine), a program of Second Nature, under the auspices of a NIEHS grant to gather and disseminate environmental health educational resources over the internet in order to help medical and allied health sciences faculty identify, locate and use resources for incorporating environment and health perspectives into their curricula. CEEM has authorized the use of these materials on this website for archival purposes. Please note that the copyright for this material is retained by the instructor and/or contributing institution.