Student manual

STUDENT MANUAL
Core Competencies – Core Topic
ANTIMICROBIAL THERAPY
Developed by:
Ashir Kumar, M.D.
Pediatrics and Human Development
Daniel H. Havlichek, M.D.
Internal
Medicine
College of Human Medicine
Michigan State University
Core Competencies -- Core Topic: Antimicrobial Therapy
Antimicrobial Therapy
Upon completion of the unit, the student will be able to: • Distinguish appropriate and inappropriate selection of chemoprophylaxis and other prevention measures (vaccines) for infections in high risk patients. • Discuss appropriate vs. inappropriate antibiotic dosage in pediatrics. • Discuss appropriate patient follow-up for patients with infectious diseases. • Identify some factor leading to the development of antibiotic resistance in bacteria. • To explain how prior antibiotic treatment influences diagnostic testing • Discuss appropriate indications for antibiotic use • Discuss side effects and complications of antibiotic therapy • Explain the complications and management of intravenous lines • Explain pharmacology of specific antibiotics • Understand definitions of systemic inflammatory response syndrome (SIRS). Core Competencies -- Core Topic: Antimicrobial Therapy
CASE ONE – PAGE 1
R.C. is a 5-year old African-American male who was seen in his pediatrician's office for preschool physical. On review of systems it was discovered that the patient has sickle cell disease. Physical examination revealed a developmentally appropriate child with height and weight at 10th percentile, mild pallor, liver 2cm palpable in right mid clavicular line, and spleen tip palpable. Rest of the examination was unremarkable. Besides receiving DTaP, IPV, and MMR vaccines, patient was also prescribed amoxicillin 250mg once a day po as prophylaxis for pneumococcal infections. Patient was given a prescription for amoxicillin, one month supply with six refills. Five months later R.C. is taken to an emergency room because of nasal congestion and occasional cough. No other symptoms were reported. R.C. was prescribed azithromyicin for 5 days for otitis media. Two weeks later he was again seen in the emergency room because of persistent nasal congestion and feeling of fullness in his head. No other symptoms were reported. Patient was given a prescription for Augmentin for 10 days for sinusitis. Two weeks later, his mother calls the physician's office regarding a slight swelling and pain in the ankle area that R.C. developed two days ago. There was no fever and appetite was slightly decreased. The physician told the mother to give R.C. acetaminophen 250mg TID, encourage him to take plenty of fluids, and increase the dose of amoxicillin to 500mg TID and contact him again on Monday (after the weekend) if R.C. was still sick. Next day (Saturday) R.C. developed high fever (up to 103oF) and swelling and pain in the right ankle. He did not want to walk. Mother followed the instructions given by the physician. R.C. had a restless night. The next morning (Sunday) his temperature was up to 104.5oF, and his ankle was almost the size of a baseball. Patient was taken to a hospital. R.C. is admitted to the pediatric ward and is evaluated by his pediatrician, an orthopedic surgeon, infectious disease consultant, and a hematologist. Physical examination reveals: Core Competencies -- Core Topic: Antimicrobial Therapy
Liver 2cm palpable in right mild clavicular line, spleen tip palpable Right ankle – swollen, erythematous tender; child resists all active and passive movements. Skin overlying the swelling is intact. No lymphangitis Patient has tender lymph nodes in right popliteal fossa 17,800/mm3 Segs 63%; Bands 10%; Lymphs 27% Joint fluid aspiration: 15ml of cloudy fluid; WBC 75,000/mm3; Segs 75%; Monos 25%; Glucose 20mg%; Protein 4.5gm% Gram stain: numerous white cells; no organisms seen Ankle x-ray: no bony destruction, generalized effusion in the right ankle joint Chest x-ray: no pulmonary infiltrates, cardiac size normal Blood and joint fluid cultures are negative after 24 hours Antimicrobial therapy was with cefotaxime 200 mg/kg/day was started Blood and joint fluid cultures grow rare gram-positive cocci after 48 hours of incubation, which are later identified as Streptococcus pneumoniae. Two days later, micro laboratory called the pediatric ward to inform the resident in charge of the case that Streptococcus pneumoniae isolate was highly resistant to penicillin as well as to cefotaxime. (MICs: Penicillin 3 μg/ml, cefotaxime 4 μg/ml, susceptible to vancomycin, clindamycin and rifampicin) Core Competencies -- Core Topic: Antimicrobial Therapy
CASE TWO -- PAGE 1

J.R. is a 38-year old white woman who had been in excellent health until the fall of 1998. At that
time, she developed fever, fatigue, malaise, and stiffness in her joints. Her temperatures were
always less than or equal to 100.5oF and she sought evaluation from her primary care provider.
The patient denied skin rashes or photophobia. She was married and had three children under the
age of 10. Travel history: No travel to the East coast since the age of 12. She had not been to the
Upper Peninsula. She did not camp, hike, or participate significantly in outdoor sports.
Her CBC, comprehensive panel, sedimentation rate, ANA, and Lyme antibody titer were
negative or normal.
Because her neighbor was diagnosed with Lyme disease she sought evaluation at a regional
clinic, which specialized in this problem. There she had a negative examination and a negative
Lyme antibody titer. A urine Lyme antigen assay (a research test) was positive. The patient was
given oral doxycycline for 30 days. During this period of time she developed abdominal pain,
vaginitis, and some diarrhea. She noted waxing and waning of her symptoms and a little
improvement.
Because the patient did not improve and the physician felt the patient “likely had Lyme disease," a course of intravenous ceftriaxone was prescribed. The patient had a percutaneous intravascular central catheter (PICC) placed. The patient received intravenous ceftriaxone 2gm once a day. At the start of the third week of therapy the patient noted fever, chills, and abdominal pain. Her fever and chills became progressively worse and she was admitted to the hospital with a diagnosis of presumed sepsis. At the time of admission the patient had a temperature of 103oF, BP 100/60, pulse 110 (which was regular), respirations of 28 and regular. Her skin exam showed numerous tender nodules on the fingers and hands and occasional petechial lesions on the chest. She had a 2-3/6 harsh systolic murmur heard best at the apex and radiating into the axilla. The abdomen was soft and nontender without organomegaly. The PICC line site showed no erythema.Two sets of blood cultures were obtained and after 24 hours all four bottles were positive for gram positive cocci in clusters. The patient was started on intravenous nafcillin, 2 gms every 4 hrs; and the PICC line was removed. Core Competencies -- Core Topic: Antimicrobial Therapy
CASE TWO -- PAGE 2
On day two, the patient’s creatinine had increased to 2.3 and her nafcillin was decreased to 1 gm every 6 hrs. One day three, the patient spiked a fever to 105oF and became hypotensive (BP 60/40). She was managed with fluids and pressors and transferred to the Intensive Care Unit. At that time, her antibiotics were changed to vancomycin, gentamicin, and rifampin. The patient continued to require inotropic support and remained febrile for 5 days. Original and follow-up blood cultures on days 3 and 5 showed methicillin resistant Staphylococcus aureus. The patient stabilized and after two weeks was discharged home on intravenous vancomycin therapy and completed a six-week course. Core Competencies -- Core Topic: Antimicrobial Therapy
CASES ONE AND TWO
Recommended Readings
1. Infectious Disease Guidelines by, Topic, National Center for Infectious Diseases – 2. Modifying Antibiotic Prescribing in Primary Care. A.Y. Peleg and D.L. Paterson.
Clinical Infectious Diseases 42:1231-1233, 2006 3. Controlling Antrmicrobial Resistance in Hospitals: Infection Control and Use of Antibiotics. R.A. Weinstein, Emerging Infectious Diseases 7(2) March – April 2001 –

4. Preventing Surgical Site Infections: A Surgeon’s Perspective. R. L. Nichols, Emerging
Infections Diseases 7(2) March – April 2001 5. Staphylococous aureus bacteremia and Endocarditis. C.A. Petti and V.G. Fowler, Jr.,
Infectious Dis Clin North Am. 16(2) 413-435, 2002. 6. The prevention and treatment of Bacterial Infections in Children with Asplenia or Hyposplenia: Practice Considerations at the Hospital for Sick Children, Toronto. V.E.
Price, S. Dutton, V.S. Blanchette, et al. Pediatric Blood Cancer. 46: 597-603, 2006
7. Otitis Media – Principles of Judicious Use of Antimicrobial Agents, Dowell, et. al.,
Pediatrics, 1998; 101Supplement: 165-171 8. Acute Sinusitis – Principles of Judicious Use of Antimicrobial Agents, O’Brien,
Katherine L., et. al., Pediatrics, 1998; 101Supplement: 174-177.

Source: http://echt.chm.msu.edu/BlockIII/Docs/CoreComp/B3CCTherAntimicTherSM.pdf