180 likes | 202 Views
Case Study: Investigating Treatment options in a patient who develops hydrocephalus and subsequent fever. Case Study: A 51-year-old man is admitted to hospital in the USA with fever and obtundation (clouding of consciousness). Actions.
E N D
Case Study:Investigating Treatment options in a patient who develops hydrocephalus and subsequent fever
Case Study:A 51-year-old man is admitted to hospital in the USA with fever and obtundation (clouding of consciousness).
Actions • A cranial CT scan is performed and samples of cerebrospinal fluid are taken for microbiological culture. A Gram stain of the fluid shows Gram-positive cocci in pairs/chains (Figure 1) • In the emergency department, the patientis started on a course of cefotaximeIV 200 mg/kg/day administered every 6 hours and vancomycin IV 60 mg/kg/day administered every 8 hours • The patient is given oral dexamethasone (8 mg four-times daily).
Gram stain of cerebrospinal fluid Gram-positive cocci in pairs
Clinical Course • Twenty-four hours after antibiotic administration commenced, the patient is awake and alert • Cultures of the patient’s cerebrospinal fluid reveal Streptococcus pneumoniaesensitive to penicillin • vancomycinis stopped • Four days after admission, obtundation recurs • A CT scan reveals hydrocephalus • An endoscopic ventriculostomy is performed to relieve the hydrocephaly and consequently improve the mental status of the patient • Five days after placement of the ventriculostomy, the patient develops a fever and peripheral leukocytosis.
Question 1 • What are the possible causes of the fever and leukocytosis?
Question 2 • What would you do now? What are your reasons for this course of action?
Investigations • A repeat CT scan shows the ventricular size to be stable with resolution of the hydrocephalus • An evaluation for nosocomial infection is begun • A sample of cerebrospinal fluid from the ventriculostomy drainage reveals the presence of Gram-negative bacilli.
Question 3 • What factors should you consider when selecting an empiric therapy for this patient and why do you think these are important?
Question 4 • What are the most important organisms for which antibiotic coverage should be provided and why?
Question 5 • Which of the following treatment options would you choose and why?
Culture Results • Acinetobacterbaumanniiis grown from cerebrospinal fluid cultures • No organisms are grown from blood, urine and sputum cultures. Analysis of these samples shows no obvious findings • Acinetobacterspp. antibiotic susceptibility results show: • ceftazidime resistance • gentamicin resistance • trimethoprim–sulfamethoxazole resistance • imipenemand meropenem susceptibility.
Question 6 • Given the culture results, which of the treatment options would you choose now and why?
Treatment • A carbapenem is administered at a high dose • Neurosurgery is requested to remove the ventriculostomy and evaluate the need for further management of intracranial pressure.
Source of Infection • Further investigation of the source of the Acinetobacter spp. reveals a breakdown in infection control techniques during maintenance of the ventilator in the intensive care unit (ICU).
Key learning points • Dosing of antibiotics may be different for the treatment of CNS infections • optimal dosing is important • Infection control is important in limiting the spread of antibiotic-resistant pathogens in the ICU • Indwelling devices should be removed as soon as they are no longer medically indicated
Additional Questions • Which of the AIM core principles could be applied to this case? • How could the educational value of this case be improved?
What If….? • Cultures grew penicillin-resistant Pneumococcus spp.? • Cultures grew cephalosporin-resistant Pneumococcus spp.? • Ventriculostomydrainage showed Gram-positive cocci in clusters and culture of the fluid subsequently grew methicillin-resistant Staphylococcus aureus? • The patient had a history of urticarial reaction to penicillin and was wearing a medical bracelet documenting his allergy?