Note: Much of the information to answer the questions in this case can be found in Infectious Diseases in 30 Days by F. S. Southwick, McGraw-Hill, 2003.
A twenty-two-year-old Caucasian female presents at the University Hospital clinic with a complaint of fatigue and lack of appetite that had started several weeks ago, she was unsure of the exact time as it had been very gradual. She also reported that she had had a fever for the past two days and had been having night sweats. Although she was an experienced runner she had been unable to run the distances she previously had due to shortness of breath. She had recently arrived from the former Soviet Republic of Georgia to study and to collaborate in studies of bacteriophage therapy at the University. Shortly after arriving here she had had a wisdom tooth extracted that had been bothering her for some time. This was approximately 2 months before she came to the clinic.
Question 1 - Single Best Answer
What are some of the things you might consider without any further information? Bugs Database
AIDS tuberculosis infectious mononucleosis subacute bacterial endocarditis all of the above
Question 2 - Single Best Answer
What is the causative agent of infectious mononucleosis?
HHV 1 CMV Epstein Barr virus Escherichia coli Staphylococcus aureus
Question 3 - Single Best Answer
What is subacute bacterial endocarditis?
an immunologic reaction that harms the heart valves a lesion of the heart caused by an intracellular bacterium invading the heart muscle a growth of bacteria on a heart valve
She has not had a sexual relationship for the past six months, and therefore does not believe she has a sexually transmitted disease. She had mono when she was 15. She reports no problems with urination. She drinks alcohol only occasionally and does not smoke. She denies the use of illegal drugs, and has no allergies.
She says that she has not felt hungry at all for the past four days and has lost several pounds. She denies ever having been treated for an eating disorder. She claims to have never thought of harming herself or others, nor has she had psychiatric counseling of any kind. She has never had a major illness except for scarlet fever when she was ten. This was not treated and disappeared by itself. She was diagnosed with rheumatic fever 3 months later, but this has never limited her activities. Other than that she has been in good health until now.
Question 4 - Single Best Answer
What is scarlet fever?
viral infection similar to measles a high fever caused by sunburn an infection by Streptococcus pyogenes one of the rickettsial fevers like Rocky Mt. Spotted Fever
Question 5 - Single Best Answer
Is scarlet fever related to rheumatic fever?
Yes No
Question 6 - Single Best Answer
What does the fact that she had rheumatic fever (R.F.) strengthen in your differential diagnosis? Bugs Database
definitely a UTI as these can be caused by Staphylococcus and so can rheumatic fever definitely a psychological problem as recent evidence links the immune system to the neuroendocrine system and R.F. is immune-based she might have another problem with her heart now it is probably mono; this is associated with rheumatic fever due to a predominance of certain tissue types in the R.F. population nothing - once this goes away there are no further problems.
Question 7 - Single Best Answer
She appears to have linear reddish brown streaks under her fingernails. What are these called?
Osler nodes splinter hemorrhages Janeway lesions dirty fingernails
Question 8 - Single Best Answer
What disease do splinter hemorrhages suggest? Bugs Database
RMSF cat scratch disease endocarditis Herpes whitlow bacterial meningitis
Question 9 - Single Best Answer
You also note a pea-sized erythematous nodule on one toe that is somewhat painful. What is this called?
Osler node splinter hemorrhage Janeway lesion NBTE
Question 10 - Single Best Answer
What is the pathogenesis of the splinter hemorrhages and Osler nodes?
emboli lodging in distal capillaries toxins produced by the bacteria in the heart deposition of immune complexes death of the endothelial cells caused by bacteria growing in them
Her spleen is slightly enlarged but she appears to have no abdominal pain. Her lung fields are clear, but upon auscultation of her heart, you hear a mild systolic murmur. The heart is of normal size, and you hear no rubs. You admit her to the hospital and order tests. Her temperature holds steady at 100.5 F
Question 11 - Single Best Answer
What laboratory test(s) would you order? Bugs Database
urine culture Gram stain of blood blood culture spinal tap cat scan
Question 12 - Single Best Answer
What bacteria are in her blood? Bugs Database
Salmonella or Shigella Staphylococcus aureus Streptococcus pyogenes viridans Streptococci Streptococcus pneumoniae there are two possible answers above, one can’t tell with absolute certainty
The bacteria could be either Streptococcus pneumoniae or one of the viridans Streptococci, based only on the laboratory results. However only one of them is a likely cause of endocarditis.
Question 13 - Single Best Answer
Which one is the likely cause of endocarditis?
Streptococcus pneumoniae viridans Streptococcus
Question 14 - Single Best Answer
How could one differentiate between the two alpha hemolytic Streptococci?
bacitracin disc optichin disc citrate test
Question 15 - Single Best Answer
What are viridans Streptococci?
all catalase positive Streptococci all coagulase negative Streptococci all hemolytic Streptococci Streptococci that cause blood agar to turn green when they grow on it all bacteria found in the mouth
An optichin test confirms that the bacteria in her blood is not Streptococcus pneumoniae; i.e., it is one of the viridans Streptococci. Based on these results and the heart murmur, you begin antibiotic therapy with Penicillin G at 4,000,000 units every four hours. You also order an echocardiogram of her heart.
Question 16 - Single Best Answer
What is the purpose of the echocardiogram? Bugs Database
ordering more tests means more money for you you suspect pneumonia that will dull the echos in the echocardiogram she may be pregnant penicillin causes an unusual resonance pattern in blood. to confirm endocarditis and evaluate any damage to the valve
Question 17 - Single Best Answer
It is confirmed that she has endocarditis caused by a viridans Streptococcus. Where did these bacteria come from? Bugs Database
From eating contaminated food From an insect bite From a cat bite From casual contact with another person who had endocarditis From the dental procedure
Question 18 - Single Best Answer
What other procedures commonly cause a transient bacteremia?
chewing gum brushing teeth upper GI endoscopy transurethral prostatectomy all of the above
Question 19 - Single Best Answer
What bacteria cause the most serious cases of endocarditis?
Streptococcus pyogenes Staphylococcus aureus E. coli Pastuerella multocida viridans Streptococci
Question 20 - Single Best Answer
What lesion commonly precedes bacterial endocarditis?
Janeway lesion Venturi effect Nonbacterial thrombotic endocarditis (NBTE) Osler node
The next day her fever breaks, and she accepts soft foods. Until then she had been given IV glucose to compensate for her lack of nourishment. She is given intravenous penicillin for fourteen days before being sent home with orders to rest. The lab identifies the bacteria as Streptococcus salivarius. She gets back to work more ready then ever to continue her studies on phage therapy.
Question 21 - Single Best Answer
What is phage therapy?
using macrophages grown in vitro to treat infections using lytic bacterial viruses to treat bacterial infections using antibiotics to kill the phage-infected bacteria that are often responsible for producing toxins
Question 22 - Single Best Answer
Besides rheumatic fever, what else can predispose to endocarditis?
Congenital heart disease Mitral valve prolapse Prosthetic valve All of the above
Question 23 - Single Best Answer
Endocarditis is becoming increasingly rare in the US, especially amoung young people. To what can this be attributed?
Flouride in the water Better treatment of Streptococcal sore throat Better sanitation Higher vaccination rates
Question 24 - Single Best Answer
What could have prevented this case of endocarditis?
vaccines that are not available outside of the US prophylactic antibiotics before her dental procedure a daily regimen of antibiotics as is prescribed for all rheumatic fever patients more careful work by the dentist
Question 25 - Single Best Answer
Besides endocarditis, what other active infections of the heart are there?
Rheumatic fever pericarditis impetigo syphilis