Case #28

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There are two parts to this case.  Make sure you complete each of them.

Introduction to the Agromedicine/Toxicology Cases

The following cases were developed to give the student an appreciation for the manner in which a toxic exposure situation might present to a primary car provider. This is especially important in our present climate of increased threat from acts of Bioterrorism. The principles involved extend to the recognition of the clinical presentation of a wide variety of signs and symptoms that might result from a Bioterrorism incident as well as a toxic exposure. The goal is to use examples of representative cases involving toxins to which a broad range of our population is exposed. This recognition extends to many other scenarios, which could be the first indicator of a terrorist related incident or a clinical problem with public health implications.

Toxic exposures can occur in a wide variety of situations and settings. As an example, and contrary to popular belief, most pesticide exposures in Pennsylvania occur in urban or suburban environment rather than on the farm. Awareness of an unusual grouping of symptoms or a specific risk activity can be the key to diagnosis in individual cases. Often the patient can provide this information, though it may not be readily volunteered. This re-emphasizes the importance of a careful history. An unusual clustering of cases with common or unique symptomology may indicate a disease outbreak or mass exposure. An example of this was the original recognition of Legionnaires Disease through the alert reporting of a cluster of cases of a severe respiratory syndrome in older men who had attended a convention in Philadelphia by a local physician in upstate Pennsylvania.

Recognition of illness associated with the intentional release of a Biologic Agent is, as previously described, another aspect of this subject area. The following are some indicators and diagnostic clues to the possible presence of a Bioterrorism related presentation.

  1. An unusual temporal or geographic clustering of illness;
  2. Signs and symptoms suggesting an unusual infectious disease outbreak, especially involving unexplained febrile illness associated with sepsis, pneumonia, respiratory failure or rash;
  3. An unusual age distribution for common diseases. An example would be a chicken pox like outbreak in adults, which could indicate smallpox.
  4. A large number of cases of flaccid paralysis, which might indicate a Botulism toxic exposure.
  5. A clustering of patients presenting with signs and symptoms of organophosphate poisoning – rhinorrhea salivation, brocho-spasm dyspnea, vomiting, diarrhea, fasciculation’s, agitation, seizures, paralysis, etc. Several common toxins with Bioterroristic potential are related to this class of pesticides.

Hopefully these cases will give you a broad appreciation for the importance of the recognition of the unique and unusual or the common syndrome with a twist, which may have profound implications for your individual patient or for your community and nation.

The development of these cases was supported by the Pennsylvania Agromedicine Program and funded by the Pennsylvania Department of Agriculture.

Chief Complaint - Case Scenario A

A 30-year-old man comes to your office accompanied by his wife who insisted he get evaluated. He complains of headaches for the last few months. He describes a generalized headache, dull and steady, present practically all day but worse as the day goes on. His wife says he gets more irritable than she remembers and he seems confused at times. There is no past or family history of headache. Review of systems is positive for occasional nausea, lightheadedness at times and a red, dry rash on the hands in the last month or two for which he has been using 1% hydrocortisone cream and medicated powder at night with little improvement.
 
  1. What issues have been identified so far?
  2. What headache types would you include in the differential diagnosis so far?

Social History

Social history shows him to be married with two children ages 7 and 5 in good health. He finished high school, entered the Navy where he was an engineman. After discharge, he took over his grandfather’s farm, something he had planned since childhood. His Naval experience prepared him to repair farm equipment and to engage in his avocation of repairing old cars. He smokes a pack per day since age 18 and consumes 4 beers per week. He has had no hospitalizations or significant illnesses.

He and his family live on the farm. They have well water, which only he drinks because his wife says, “It tastes and smells funny.”  
 
  1. What has this additional history added to the differential diagnosis?

Social History (con't)

When questioned, he tells you he does work in a garage with only one window open far to the other side of the area. He keeps the main garage door closed “to keep the dust out.” He has gasoline in the garage, which he uses as a solvent (he did this in the Navy even though it was against regulations because it was abundant.) He says it never bothered him there when he repaired helicopters (although the work area was very well ventilated on the ship.) He also uses a kerosene space heater in the winter.

  1. How much exposure to volatile vapors, such as, gasoline is needed to cause problems?
  2. Is it relevant that he consumes well water and his family does not?
  3. Is the space heater relevant?

Physical Examination
  • Physical exam shows normal vital signs.
  • HEENT exam shows mild conjunctival injection. Extraocular movements are intact without nystagmus.
  • Cardiac, lung and abdominal exams are normal.
  • Skin shows erythema and dry, flaky skin on the hands with some minor fissures and ground in grease.
  • Neurologic exam shows a slight difficulty with heel-toe walking and very slight tendency to fall to one side on Romberg testing but no other focal neurologic abnormalities.
  1. What are the pertinent signs on exam and why?
  2. What diagnostic testing should be done?
  3. Would pulse oximetry rule out carbon monoxide poisoning?
  4. What treatment would you recommend?
  5. Is it necessary to test the well water?

The patient has improved ventilation and avoided the use of solvents, especially gasoline, in closed areas. He has purchased protective gloves to use when handling solvents. Triamcinolone 0.1 % cream has improved his rash and his headache and other symptoms are resolved. He returns for a recheck appointment and has a normal neurologic exam.
 
  1. What else should you consider on this follow up visit?

Chief Complaint - Case Scenario B

A 40-year-old carpenter presents to his family physician office with a complaint of onset of a number of symptoms over the last 12 hours.  He has developed mouth sores and ulcerations on his lips, blurred vision, ataxia, diffuse myalgias with muscle fasciculations, diffuse paresthesia, headache, slight confusion and an overall sense of weakness.  These symptoms are progressing since last evening.   He is very concerned that something is seriously wrong.  He is in excellent health and is not taking any medication.  He has not traveled out of the area.  He has some abdominal cramping and diarrhea, but no vomiting, no skin rash except for the ulcerations.

He is currently employed remodeling a home in a residential area.  The day before his presentation to your office, he was working outside at the home.  Nothing unusual happened, except that when he was eating lunch on the lawn, a lawn care service man did the monthly spray.  His symptoms began a few hours later.
 
  1. What would you include in your differential diagnoses?
  2. What questions may help you to narrow your diagnosis?

Physical Exam

 Patient is afebrile, blood pressure is normal and pulse rate is 100 beats/minute.

Neurological exam shows general increase in deep tendon reflexes, ataxia is present and muscle fasciculation’s can be observed. The patient has evidence of a peripheral neuropathy, and has difficulty with fine motor coordination of his hands.

Skin exam shows numerous ulcerations on his lips and a mild dermatitis on the face.

 
  1. Which of the following would you like to do for this patient?
      - Admit the patient to the hospital.
      - Order a MRI of the brain.
      - Perform a spinal tap.
      - Call the lawn care company for information and assistance.
      - Order a toxicology screen.
      - Consult with neurology or toxicology.
  2. What other ways could you get information on the toxic agents and their treatment?
  3. What is 2,4D?
  4. What is the treatment for 2,4D toxicity?
The patient is admitted to the hospital where a urine sample confirms the agent.

He is treated by aggressive diuresis with alkalization of the urine to a goal of a pH between 7.6 to 8.8. You monitor the potassium carefully to compensate for the forced diuresis (urine flow of 4-6 ml/min.) Over the next 24 hours many of the symptoms start to clear and the patient was discharged 48 hours after admission. The blurred vision, poor motor coordination, headache and fasciculation’s took about 3 months to resolve.

By using the MSDS or the information at the mentioned web sites answer the following questions.
 
  1. How long can the residual remain active in the soil?
  2. Is this agent a carcinogenic?
  3. How does the body absorb the agent?
  4. Why is 2,4-D is considered “Highly Toxic”
Very high dose exposures have produced behavioral changes progressing to comas. Renal failure and subsequent electrolyte disturbances leading to cardiovascular instability are associated with fatal cases. Persistent symptoms may include neuropathy, myopathy, myotonia and muscle weakness.
 

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This page was last updated on April 24, 2006
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