Case 1 - You are at your son's baseball game when another boy's dad
experiences dizziness and nearly faints in the stands next to you. You
tell him that you are a paramedic and will walk him to your car where
you have your medical equipment. He reports that he has had a headache
off and on since he had a tooth extracted four days ago. This evening
he is feeling very weak.
His blood pressure is normal. When you listen to his heart you note that he has a pronounced murmur. He reports having had rheumatic fever 15 years ago. You examine his fingernails and find one that has tiny petechial hemorrhages under it.
1) Which cardiovascular infectious condition is this?
2) What is the most likely causative organism and the route of transmission?
Streptococcus viridans; Commonly found in the mouth where it entered the wound.
3) What's the connection, if any, with rheumatic fever?
Damage to heart valves which can lead to bacteria attaching. Strep viridans is the number one cause of subacute bacterial endocarditis.
4) Why did you look at his fingernails?
Capillary hemorrhaging; oxygen in bloodstream
Eyes are another place to look other than the fingernails
5) What type of culture would a physician most likely order, and why?
BAP to look for hemolysis; alpha= hemolytic
Case 2 - A 63-year-old international telecommunications executive visits your office with complaints of a high fever. The fever is not constant, but intermittent. When you press him for details he estimates that every three days or so he suffers these debilitating "sweats." He usually has headaches and muscle aches during the episodes. They keep him home from work. After half a day or so he feels better. He reports that he has experienced these episodes for about two months.
1. What is the name of the condition you
2. What should be your first question about the patient's history?
Have you traveled recently and, if so, to where?
3. What is the most likely causative organism (genus and species)? Support your answer.
4. Is this pathogen eukaryotic or prokaryotic?
5. Which is the most dangerous of the species that can cause this disease? Give some details.
Plasmodium falciparum is the most dangerous because it causes celebral malaria.
6. What are the two main places in the human body that are exploited by the causative organism in this disease?
The liver and blood cells
7. Can this individual transmit this infection to others? Why or why not?
No, you have to be bitten by the mosquito vector.
Case 3 - You've decided to work in the Peace Corps for the first two years after graduating from nursing school. Your assignment is in a rural area in South Africa. You and a coworker are setting up a clinic and encouraging women from the surrounding villages to bring their children when they are ill and visit the clinic themselves, especially when they are pregnant.
1. In your first week you saw several children whose major symptoms
were high fever, lots of sweating, and prostration (total exhaustion
or weakness). They all turned out to have the same infectious
condition, one that you continued to see throughout your stay in South
Africa. Up to half of the sick children did not survive this illness.
What is it?
2. In this setting, what is the best prevention for this disease?
3. In your third month you saw a 2-year-old boy with an angry-looking rash. He was very ill with a high fever, and eventually died. His death surprised you because you thought this disease had been conquered long ago. (In the United States it is seen only occasionally because children are vaccinated for it.) Over the course of your two-year stay you saw these symptoms in children perhaps a dozen times. Several of the children died. What is the disease?
4. Name at least two of the most common infectious conditions you should look for in adult clients in this setting.
Malaria and HIV/AIDS, TB
Case 4 - A newspaper report from Boston in the late 1990s described a growing fear among local residents. They were afraid to venture outdoors because of the increasing visibility of a particular infectious disease. The article reported that the number of people hiking in Massachusetts had recently decreased dramatically, and that many homeowners were erecting fences and spraying their yards with pesticides. Many people who dared to venture outdoors wore white clothing and tucked their pants inside their socks. In New York, there were reports of residents simply paving over their lawns, and some gave up gardening altogether.
1. What infectious disease do you suppose these cautious citizens
were trying to avoid?
2. What determines which geographical region of the country carries risk of this disease for its inhabitants?
Heavily forested areas with lots of deer. Borellia burgdorferi
3. Another major disease in the United States is transmitted in a similar way. What is it, and what microorganism causes it?
Rocky Mountain spotted fever (Rickettsia rickettsi)
4. Which regions of the country have a high incidence of this second tick-borne disease?
Forested regions especially in the South around the Mississippi.
5. Which of these two diseases frequently has no skin manifestations at all?
Case 5 - You're at the beach on Lake Michigan with your friends over
spring break. The house you're staying in is a few blocks away from
the beach, and the flower border around the house is overgrown with
weeds. There is a tiny concrete patio next to the house where the four
of you crowd to lie out in the sun when you're not at the
Everything is fine until Janet complains of an insect bite on her ankle. It looks like a big mosquito bit. You rummage around under the sink in the bathroom and find a very old bottle of aloe lotion. She rubs it on the bite and you both return to the patio.
The next day Janet's ankle is very red in the area around the bite. It is hot and tender to the touch. Being nursing students, you decide not to take a chance and you drive her to the local hospital's emergency department to have it looked at. You wait there for four hours while other, more seriously ill patients are seen before you. It's your last day at the beach, and even Janet is beginning to feel it's not worth wasting the day in the waiting room. So you leave the hospital without seeing a doctor.
You go back to the house and Janet puts more aloe lotion on the bite. Then off you go to the lake. That night Janet's roommate wakes you at 2 a.m. saying that Janet is crying and sweating. When you get to her room you see Janet looks very ill. She is covered in sweat but is shivering. She is very pale, almost blue in places, and there are red patches on her legs. You dial 911
1. What do you suppose is happening with Janet? Is it dangerous?
Based on Janet's symptoms it would appear that she is suffering from cellulitis, which is an infection caused when bacteria enters through cuts or other openings in the skin. Usually cellulitis affects the skin on the lower extremities and presents as red, swollen skin that can be tender to the touch. Other common signs and symptoms include red spots, warmth, pain, fever, and blisters. If left untreated, Janet's infection could spread to the lymph nodes and blood stream (septicemia) and quickly become life threatening.
2. Explain Janet’s symptoms described in the last paragraph of the case.
She is obviously experiencing a fever in response to the poison that has been injected as well as
Blue skin - lack of oxygen
Sweats/chills - fever
Red patches - vasodilation
3. What is the organism causing this condition?
The most common types of bacteria that cause cellulitis are group A Streptococcus and Staphylococcus. MRSA, can also cause cellulitis. The bacteria enter the skin through cuts, scrapes, wounds, or any type of puncture that can allow entry. Cellulitis from a bug bite doesn't transfer from the insect itself, but a bite pierces the skin and creates a portal of entry for bacteria that may exist on the skin. Scratching a bite can also transfer bacteria from the fingernails into the site.
4. When you relate the history of Janet's condition to one of the paramedics you notice that she writes "secondary to cellulitis" on her pad of paper. What is cellulitis, and what does it mean that Janet's condition is "secondary" to it?
Cellulitis is an bacterial infection of the skin that can sometimes be fatal and can often lead to septicaemia. What secondary to means its not the primary cause but in relation to the primary cause cellulitis. For example she developed the cellulitis from the infection then the septicemia came
5. How should Janet's condition be treated at this point?
So firstly they should watch her blood pressure and vital signs. Then cultures should be draw to identify the causative bacteria and the correct IV antibiotic to treat that organism. From there she should be monitored closely by providers to prevent severe sepsis.
Case 6 - Your son's best friend, Josh, has infectious mononucleosis; he hasn't been in school for two weeks. Your son and three of his friends come over after basketball practice looking for snacks, but they also want to talk to you about Josh's infection because they know you are a physician's assistant. They are all afraid to visit Josh, but they want to know when they can expect him back at practice. One of the boys asks you what causes "mono." Another one of the boys says he heard it was a form of herpes. All of the boys cringe at that one. Can you help these guys out with some information?
1. What causes mono, or infectious mononucleosis? What do you know about this agent?
Ebstein-Barr Virus (EBV) causes mononucleosis. EBV is human herpes virus 4. It is contagious, spreads through saliva. Mononucleosis can be treated with self-care and symptoms are reduced by ample rest. Sore throat can be soothed by gargling salt water.
2. What are the symptoms?
Fatigue, sore throat, difficulty swallowing, fever, body ache due to infections
3. How long will Josh be out of school? Is it okay to visit him?
2-4 weeks, as this is how long it is contagious. He probably shouldn't have any visitors, unless they're already immune to the virus (had it before).
4. You tease the boys by saying, "Besides, by the time you're adults, all of you will have it anyway." Before they recover from that shock you add, "and some of you have it right now!" Are you just playing around with them, or are these statements true? Explain your answers.
It's true, 95% of people are infected with the virus by the time they are adults. The virus is very well adapted to humans.
5. Sam, the point guard on the team says his aunt has chronic fatigue syndrome. "Isn't that caused by the same virus?" he asks. Is it?
It can, other viruses can also cause chronic fatigue
After viral infections of mononucleosis, sometimes myalgic encephalomyelitis occurs. The cause is not yet known known, but Ebstein-Barr Virus is assumed to be the causal organism.
Case 7 - In late September a woman brings her 14-year-old daughter,
Meg, to the family physician. Meg shows the doctor the back of her
thigh where there are pale red, nonraised discolorations. The rash
covers a wide area of the thigh and seems to be roughly circular. The
center of the circular area appears normal. Meg has no other symptoms,
but her mother brought her in because the rash has been present for
over three weeks and it seems to be growing.
The doctor questions Meg about possible exposures. Has she worn any new pants lately? Has she been in the woods? Do her joints hurt? Meg reports that she spent the month of August at summer camp in Vermont. She's been wearing mostly shorts and bathing suits for the past two month, none of them new. She doesn't remember any insect bites on her thigh.
1. On the basis of Meg's oral history, what is the most likely diagnosis? What would the causative microorganism look like in a Gram stain?Lyme's disease. Spirochete.
2. How did she most likely acquire her infection?
Tick bite carrying Borrelia burgdorferi.
3. Would the diagnosis be any different if Meg had attended camp in Arizona? Explain.
Yes. It wouldn't be Lyme disease because there are most likely not carrying ticks in Arizona.
4. Why does the doctor ask Meg if her joints hurt?
Lyme's disease can cause pain in the joints, even at an early stage.
5. How is this infection treated?
Since Borrelia burgdorferi is a bacterium, Lyme disease is treated via antibiotics.
6. Meg's mom, upon hearing the presumptive diagnosis, declares that Meg will not return to that camp, which she loves and had planned to attend next summer. The doctor suggests that Meg need only take some precautions. How can she protect herself from getting this infection again?
Wearing white clothing
Stuffing her pants into her socks
Use insect repellent that's effective on ticks.