Antibiotic Cases

Antibiotic Cases
March, 2005

Below are 14 clinical vignettes including some questions. For these exercises students are asked to write their responses to these vignettes and questions and to be prepared to discuss them at the conferences on Wednesday and Thursday of next week. Some of the vignettes ask for or imply some primary antibiotic therapy. Identify the therapeutic agent and be able to justify your choice.

Clinical Vignettes

An 82 year-old man hospitalized for a fractured right hip develops nosocomial bacteremia due to an antibiotic resistant Pseudomonas aeruginosa. His organism is susceptible to only ceftazidime, tobramycin, and amikacin. His serum creatinine and BUN (tests of renal function) are normal. What combination antibiotic therapy would be appropriate for treatment of this patientÕs infection? What patient factors must be considered when dosing aminoglycosides?
A 65 year-old man is found to have a positive tuberculin skin test. The test was negative one year ago. His chest radiograph is normal. He is started on isoniazid but when you see him in follow-up 3 weeks later he is complaining of yellow discoloration of his skin and eyes, nausea and fatigue. The patientÕs symptoms indicate toxicity of what organ? Are there alternative treatments for this patient?
A 18 year-old woman of Mediterranean descent is given sulfisoxazole for cystitis. After two days of therapy she develops jaundice, dark brown urine and complains of low back and abdominal pain. Her signs and symptoms indicate what condition? Explain the biochemical basis for this condition. What other antibiotics could be used to treat her cystitis? If she tells you she has very little money to pay for a prescription drug, what antibiotics might be prescribed for her? How many days of therapy should the patient receive antibiotics?
Fifty year-old smoker with fever, cough productive of yellow sputum, and right middle lobe infiltrate. What is the most likely etiology of his infection? How would you treat this patient?
A 10 year-old boy who develops redness, warmth, and tenderness in a localized area on his right forearm three days after falling off his bicycle and abrading his arm. His mother said he developed a rash when he received amoxicillin for otitis media one year ago. How would you treat this patient?
A 25 year-old man with multiple sexual partners presents with dysuria and penile discharge. What is the most likely diagnosis in this patient? What organism is most likely the cause of his infection? How should he be treated?
A 55 year-old woman in previously good health develops fever, severe headache, and a stiff neck. Lumbar puncture shows many neutrophils but not bacteria are seen. What is the most likely diagnosis? What antibiotic(s) would you select to empirically treat this patient? Describe the antibiotic properties that are important in determining your selection and success of the drug in treating this infection.
A 28 year-old woman with advanced HIV infection and cryptococcal meningitis. What is the optimal treatment for her cryptococcal meningitis? What are the potential adverse effects of the agents used for treatment? What clinical parameters need to be monitored during therapy with these drugs?
A 22 year-old pregnant woman with bacterial sinusitis. What antibiotics would be "safe" to use to treat this patientÕs infection?
A 50 year-old woman with metastatic breast cancer and profound neutropenia following chemotherapy develops fever of 103¡F. What are the potential sources of infection in this patient? Is combination antibiotic therapy indicated in this patient?
A 30 year-old man recently found to have HIV infection. His CD4 count is <200 cells/mm3 and his viral load is 60,000 copies/mL when measured on two occasions. What initial antiretroviral therapeutic regimen would you recommend for this patient and why?
A 40 year-old man with diabetes mellitus and renal failure has an infected foot ulcer. He receives hemodialysis three times a week. Pending culture results, you are considering treating him empirically with wither piperacillin/tazobactam or cefepime. How will you determine the dosage to give this patient?
A 30 year-old woman with a prosthetic heart value is anticoagulated with coumadin. She is also taking oral contraceptives. She is advised to take rifampin for prophylaxis after close exposure to someone with meningococcal meningitis. The patient asks you for your opinion of what she should do. What will you tell her?
A 50 year-old man is receiving clindamycin for treatment of an anaerobic lung abscess. On the 5th hospital day he develops watery diarrhea and lower abdominal pain. His stool is positive for Clostridium difficile toxin. What treatment would you recommend for his diarrheal illness and why? What side effect of the treatment should the patient specifically be warned about?