What to order and rule out for an 84-year-old patient presenting with generalized weakness, tachycardia, and hyperthermia (fever)?

From the Guidelines

For an 84-year-old patient presenting with generalized weakness, tachycardia, and high fever (39.2°C), I recommend immediate evaluation for sepsis with prompt initiation of empiric antibiotics after obtaining cultures. Order a complete blood count, comprehensive metabolic panel, lactate level, blood cultures (two sets), urinalysis with culture, chest X-ray, and ECG. Consider additional tests including procalcitonin, C-reactive protein, and arterial blood gas if respiratory distress is present, as suggested by the Society of Critical Care Medicine and the Infectious Diseases Society of America guidelines for evaluating new fever in adult patients in the ICU 1. Start fluid resuscitation with crystalloids (typically 30 ml/kg) while monitoring for volume overload given the patient's advanced age. Begin empiric broad-spectrum antibiotics such as piperacillin-tazobactam 4.5g IV q6h (adjust for renal function) plus vancomycin (15-20 mg/kg IV, dosed by levels) after cultures are drawn. Rule out common sources of infection including urinary tract infection, pneumonia, intra-abdominal infection, and skin/soft tissue infections. Also consider non-infectious causes like pulmonary embolism, myocardial infarction, or adrenal insufficiency. The combination of fever, tachycardia, and weakness in an elderly patient strongly suggests infection with possible progression to sepsis, which carries high mortality in geriatric populations and requires rapid intervention to improve outcomes, as defined by the diagnostic criteria for sepsis and severe sepsis 1.

Some key points to consider in the evaluation and management of this patient include:

• The definition of fever, which can vary depending on the population and context, but is generally considered to be a temperature greater than 38°C 1.
• The use of biomarkers such as procalcitonin and C-reactive protein to guide antimicrobial therapy and reduce unnecessary antimicrobial exposure 1.
• The importance of prompt initiation of empiric antibiotics and fluid resuscitation in patients with suspected sepsis, as delayed treatment can lead to increased morbidity and mortality.
• The need to consider non-infectious causes of the patient's symptoms, such as pulmonary embolism or myocardial infarction, and to rule out common sources of infection.

Overall, the management of this patient requires a rapid and thorough evaluation, prompt initiation of empiric antibiotics and fluid resuscitation, and careful consideration of potential sources of infection and non-infectious causes of the patient's symptoms.

From the Research

Differential Diagnosis

• Infection (e.g. sepsis, pneumonia, urinary tract infection) 2, 3, 4
• Adverse drug reactions (e.g. vancomycin, ceftriaxone) 3, 4
• Systemic vasculitis or idiosyncratic reactions to medications (e.g. Stevens-Johnson syndrome) 3

Laboratory Tests

• Complete blood count (CBC) to evaluate for signs of infection or inflammation
• Blood cultures to identify potential pathogens
• Renal function tests (e.g. creatinine, urea) to assess for nephrotoxicity 4
• Liver function tests (e.g. AST, ALT) to evaluate for hepatotoxicity 2

Physical Examination

• Vital signs (e.g. temperature, heart rate, blood pressure) to assess for signs of infection or sepsis
• Skin examination to evaluate for rash or other signs of adverse drug reactions 3
• Neurological examination to assess for signs of neurological involvement (e.g. weakness, confusion)

Treatment

• Broad-spectrum antibiotics (e.g. ceftriaxone, vancomycin) for suspected infection 2, 3
• Supportive care (e.g. fluids, oxygen) for patients with sepsis or acute generalized weakness 3, 5
• Steroids for suspected adverse drug reactions or systemic vasculitis 3