CASE 2

A 21-year-old woman who is living in relative poverty with several friends in the inner city is brought to the emergency room by one of her roommates because she has been exhibiting rather bizarre behavior. When she woke up that morning, she was convinced that Martian aliens who wanted to abduct her were lurking in the kitchen, so she started to pile all of the living room furniture against the kitchen door. On the way to the hospital, the woman had frequent hallucinations and made references to elephants chasing the car, a distinct odor of cinnamon, and various other nonsensical things.

At the ER, the woman was found to have a low-grade fever. She wasn't overly coherent, so the attending physician asked her roommates if they had noticed any additional symptoms. They said that their friend had had some mild nausea and vomiting a few days earlier. She might have said something about a stiff neck as well, but they couldn't remember for sure, nor could they remember when that might have been. What they could remember for sure was that the woman experimented with some "angel dust" (phencyclidine) a few days ago, and traces of this drug were detected in her urine.

Primarily because of her history of drug use, the woman was first admitted to the psychiatric ward, where her low-grade fever persisted. She was given a phenothiazine tranquilizer in hopes of alleviating the hallucinations. After two days, however, she underwent a generalized seizure and become comatose.

Question 2.1: What is your diagnosis?

Question 2.2: What tests should you perform?

Question 2.3: What is the causative agent?

Question 2.4: What is the differential?

Question 2.5: How did the causative agent reach its present location?

Question 2.6: How prevalent is this disease?

Question 2.7: How should you treat this case?

CASE 3

A 21-year-old male college student goes on a spelunking expedition with his roommate and several other friends. While exploring a cave in southern New Mexico, the man is bitten on his left index finger by a bat who apparently resented the invasion of his home by humans. The man is urged by his friends to seek medical treatment for the bite, but he refuses to do so. About three months later, the man happens to sustain a puncture wound (from a dirty piece of glass) on his left hand. After a few days, he develops fever, which is accompanied by occasional headaches, malaise, fatigue, nausea, and an itching sensation on his left hand. He also experiences weakness in that hand and goes to the ER for help. When asked about injuries to his hand, the man mentions the recent puncture wound, but does not recall the earlier bat bite. As a result, he is treated with an antibiotic and given a tetanus shot.

Several days after his visit to the ER, the man starts to experience episodes of rigidity, hallucinations, breath holding, and difficulty in swallowing. His roommate brings him back to the ER, where his previous visit is noted and a preliminary diagnosis of tetanus or encephalitis is made. The man is intubated because he has uncontrollable oral secretions. Because of the seriousness of the situation, the physicians question his roommate the next day (when he returns to visit his friend) and finally hear about the caving incident and the bat bite.

Question 3.1: What is your diagnosis?

Question 3.2: What is the differential?

Question 3.3: What tests can you do?

Question 3.4: What is the pathogenic process?

Question 3.5: How is this disease transmitted?

Question 3.6: What is the prevalence of this disease in the U.S.?

Question 3.7: What if the man had sought treatment right after the bite?

CASE 4

A 67-year-old man is a resident in an assisted-living retirement community. He has been in generally good health during the past few years, with only a cold or two in his recent medical history. However, he begins to experience periodic fatigue, malaise, headache, and difficulty in sleeping, and these symptoms persist for about two weeks. Over the following six weeks, he experiences rapidly developing memory loss and impaired judgment, along with a steady decline in nearly all aspects of intellectual function. By the end of this period, he is in a state of profound dementia. He has blurred vision, with some loss of acuity, and he exhibits periodic myoclonus that persists when he is asleep. Loud sounds or flashes of bright light sometimes elicit startle myoclonus. The man is afebrile. His CSF appears normal and a CBC does not show any unusual findings. However, his EEG tracing shows a distinctive "burst-suppression" pattern.

Question 4.1: What is your diagnosis?

Question 4.2: What is the differential?

Question 4.3: What is the causative agent?

Question 4.4: How did the man acquire this disease?

Question 4.5: How is the diagnosis confirmed?