Initial Antimicrobial Therapy

Initial Antimicrobial Therapy

Initial Antimicrobial Therapy for Severe Sepsis with No Obvious Source in Adults with Normal Renal Function


Immunocompetent adult
The many acceptable regimens include (1) ceftriaxone (1 g q12h) or ticarcillin-clavulanate (3.1 g q4-6h) or piperacillin-tazobactam (3.75 g q4-6h); (2) imipenem-cilastatin (0.5 g q6h) or meropenem (1 g q8h). Gentamicin or tobramycin (5 mg/kg q24h) may be added to either regimen. If the patient is allergic to -lactam agents, use ciprofloxacin (400 mg q12h) plus clindamycin (600 mg q8h). If the institution has a high incidence of MRSA infections, add vancomycin (15 mg/kg q12h) to each of the above regimens.

Neutropeniaa (<500 neutrophils/L)
Regimens include (1) ceftazidime (2 g q8h) or ticarcillin-clavulanate (3.1 g q4h) or piperacillin-tazobactam (3.75 g q4h) plus tobramycin (5 mg/kg q24h); (2) imipenem-cilastatin (0.5 g q6h) or meropenem (1 g q8h) or ceftazidime or cefepime (2 g q12h). Vancomycin (15 mg/kg q12h) and ceftazidime should be used if the patient has an infected vascular catheter, if staphylococci are suspected, if the patient has received quinolone prophylaxis, if the patient has received intensive chemotherapy that produces mucosal damage, or if the institution has a high incidence of MRSA infections.

Splenectomy
Cefotaxime (2 g q6-8h) or ceftriaxone (2 g q12h) should be used. If the local prevalence of cephalosporin-resistant pneumococci is high, add vancomycin. If the patient is allergic to -lactam drugs, vancomycin (15 mg/kg q12h) plus ciprofloxacin (400 mg q12h) or aztreonam (2 g q8h) should be used.

IV drug user
Nafcillin or oxacillin (2 g q4h) plus gentamicin (5 mg/kg q24h). If the local prevalence of MRSA is high or if the patient is allergic to -lactam drugs, vancomycin (15 mg/kg q12h) with gentamicin should be used.

AIDS
Ceftazidime (2 g q8h), ticarcillin-clavulanate (3.1 g q4h), or piperacillin-tazobactam (3.75 g q4h) plus tobramycin (5 mg/kg q24h) should be used. If the patient is allergic to -lactam drugs, ciprofloxacin (400 mg q12h) plus vancomycin (15 mg/kg q12h) plus tobramycin should be used.

A 65-year-old man presents to you for preoperative workup before undergoing aortic valve replacement for aortic regurgitation (indicated because of progressive left ventricular dysfunction, as revealed on echocardiogram) and coronary artery bypass surgery. He is interested in autologous blood donation. He has had chronic stable angina for the past 2 years, which is brought on by maximal exertion; his angina has remained unchanged for 1 year. For the past 2 days he has had increased urgency for urination and dysuria. On physical examination, he has a 2/4 diastolic murmur and suprapubic tenderness; otherwise, his examination is normal.
What absolute contraindication to autologous blood donation does this man have?

A:Angina
B:Aortic regurgitation
C:Active bacterial infection
D:Age older than 60 years

Answer is C. Active bacterial infection is a contraindictaion.
Autologous blood transfusion is a general term used to describe a procedure by which previously donated (or shed) blood is transfused (or re-infused) into the same donor or patient. A substantial proportion of patients who require blood are not candidates for autologous blood donation; for example, those with acute or chronic anemia; those with active infection; those requiring urgent surgery; small children; and some patients who require cancer surgery.

A 79-year-old woman presents to your office on three separate occasions with the following average blood pressures: 190/82 mmHg, 192/76 mmHg, 194/78 mmHg. Which of the following is NOT likely to be affected by treating the patient's systolic hypertension?

a. The incidence of myocardial infarction
b. The risk for stroke
c. The incidence of left ventricular failure
d. The risk of hypertensive crisis

The answer is D. The Systolic Hypertension in the Elderly Program demonstrated that treatment of isolated systolic hypertension results in a significant decrease in the risk of stroke, the incidence of myocardial infarction, and the incidence of left ventricular failure in persons aged 60 or over. However, such treatment has not been shown to reduce the incidence of hypertensive crisis. Treatment options for isolated systolic hypertension follow the same guidelines as for systolic-diastolic hypertension. Treatment begins with nonpharmacologic therapies, including salt restriction and weight loss. Pharmacologic therapy is initited with diurectics or beta-blockers. Although overly aggressive salt restriction may be hazardous in some older adults, reduction in dietary salt intake in this case is the most reasonable initial choice.

Which one of the following tests is not always recommended in the work-up of a patient suspected of having dementia?

A. Complete blood count.
B. Imaging test of the central nervous system (computed tomography or magnetic resonance imaging).
C. Mini-Mental State Examination (or other cognitive test).
D. Liver function tests.
E. Urinalysis.

Answer is B. Tests recommended for the diagnostic work-up of dementia include a complete blood cell count (to exclude anemia and infection), urinalysis (to exclude infection), serum electrolyte, glucose and calcium levels, blood urea nitrogen, serum creatinine level and liver function tests (to investigate metabolic disease). Syphilis serology, erythrocyte sedimentation rate, serum folate level, human immunodeficiency virus (HIV) status, urine check for heavy metals and toxicology screening may be indicated in a minority of cases.
The utility of computed tomography or magnetic resonance imaging to rule out vascular disease, tumor, subdural hematoma or normal-pressure hydrocephalus remains controversial. Radiologic imaging of the central nervous system is probably not necessary in patients presenting with dementia, unless localizing neurologic signs or symptoms are noted.

Migraine with aura has which one of the following features?

A. Ipsilateral lacrimation or nasal congestion.
B. Irreversible aural symptoms indicating focal cerebrocortical or brain-stem dysfunction.
C. Reversible aura symptoms and headache with a pulsating quality.
D. Pressing or tightening quality.
E. Recurrent syncopal episodes.

C

Migraine with aura

A.At least two attacks fulfilling criterion B
B.At least three of the following characteristics:
1.One or more fully reversible aura symptoms indicating focal cerebral cortical and/or brain-stem dysfunction
2.At least one aura symptom develops gradually over more than 4 minutes, or two or more symptoms occur in succession.
3.No aura symptom lasts more than 60 minutes; if more than one aura symptom is present, accepted duration is proportionally increased.
4.Headache follows aura, with a free interval of less than 60 minutes (headache may also begin before or simultaneously with aura).

A 22-year-old gravida 2, para 1 woman with an uncomplicated antepartum course (including a screening one-hour glucose tolerance test at 28 weeks of gestation) presents for follow up. She is at 39 weeks of gestation. The birth weight of her first child was 3,500 g (7 lb, 11 oz) and the delivery was uncomplicated. On examination, estimated fetal weight by Leopold maneuver is 4,000 g (8 lb, 13 oz). The patient is concerned and wants advice about induction of labor. Which one of the following statements about induction is the most accurate?

A. Early induction increases the rate of cesarean section without favorably altering perinatal outcomes.
B. Early induction increases the rate of cesarean section and favorably alters perinatal outcomes.
C. Early induction decreases the rate of cesarean section.
D. Early induction does not affect the rate of cesarean section.

Answer is A. Given that the fetus continues to gain about 230 g (8.1 oz) per week after the 37th week, elective induction of labor before or near term has been suggested to prevent macrosomia and its complications. However, observational studies suggest that induction actually increases the cesarean section rate without favorably altering perinatal outcomes.

Ref: American Academy of Family Medicine

fetal macrosomia>4,500g
a birth weight of greater than 4,000g is also used by many clinicians and researchers to define macrosomia.
because of the risk for birth trauma and failure to progress in labor secondary to CPD, LGA pregnancies are often induced before the fetus can attain macrosomic status.
the risk for this course of action is increased rate of C/S for failed induction and prematurity in poorly dated pregnancy.
VD of the suspected macrosomic infant involves preparing for a shoulder dystocia.