Can an older adult with or without underlying neurological conditions, such as dementia, present with sepsis (blood infection) without fever and only a change in neuro (neurological) exam?

Can Older Adults Present with Sepsis Without Fever and Only Neurological Changes?

Yes, older adults frequently present with sepsis without fever, and altered mental status may be the only or earliest sign of infection—this atypical presentation is well-documented and clinically significant. 1

Key Clinical Evidence

Afebrile Sepsis in the Elderly

• 15% of older adults with documented bacteremia present without fever, including many with nosocomial infections already receiving antimicrobial therapy 1
• Elderly patients with bloodstream infections are significantly less likely to present with fever or tachycardia compared to younger adults, but more likely to have acute renal or respiratory failure 1
• The Infectious Diseases Society of America guidelines emphasize that elderly patients are more likely to have altered consciousness and less likely to have neck stiffness or fever when presenting with serious infections including meningitis 1, 2, 3

Neurological Changes as Primary Presentation

Septic encephalopathy is found in 50-70% of septic patients and may be the first—or only—organ system to show failure, particularly in elderly and immunocompromised patients. 1, 4

The neurological presentation includes: 1, 5

• Progression from slowing of mentation and impaired attention to delirium and coma
• Confusion, lethargy, and falls as presenting symptoms
• Symmetrical neurological examination findings (distinguishing it from focal CNS pathology)

Nonspecific Symptoms Replace Classic Sepsis Signs

In retrospective studies of documented bacteremia in older adults, the following nonspecific symptoms were frequently the presenting features: 1

• Lethargy and confusion
• Falls
• Abdominal pain, nausea, vomiting
• Incontinence
• Failure to eat (may be the only clue) 6

Clinical Implications and Diagnostic Approach

High-Risk Predictors in Elderly Patients

When fever IS present, these features predict bacteremia with relative risks of 3.4-15.7: 1

• Shaking chills
• Shock
• Total band neutrophil count ≥1,500 cells/mm³
• Lymphocyte count <1,000 cells/mm³

Critical Pitfall to Avoid

Do not wait for fever to develop before considering sepsis in an older adult with acute mental status changes. 1, 6, 4

The American Journal of Medicine emphasizes that typical findings of sepsis (mental obtundation, tachycardia, and fever) may be absent in elderly patients, and the time from initial presentation to first antibiotic dose should not exceed one hour. 6

Specific Diagnostic Algorithm for Older Adults with Altered Mental Status

When evaluating an older adult with new or worsening confusion: 1

1. Document vital signs including temperature (but recognize absence of fever does not exclude sepsis)

2. Assess for signs of shock: hypotension, poor capillary refill, decreased urine output

3. Obtain blood cultures prior to antibiotics if feasible, though this should not delay treatment

4. Evaluate common infection sources in elderly:

   • Urinary tract (50-55% of LTCF-acquired bacteremias) 1
   • Respiratory tract (10-11%)
   • Skin/soft tissue (10%)
   • Intra-abdominal (5%)

5. Recognize that clinical indicators alone are unreliable predictors of bacteremia in older patients 1

Mortality Considerations

The mortality implications of this atypical presentation are severe: 1, 6

• Overall mortality rates for bacteremia in LTCF residents range from 18-50%
• 50% of deaths occur within 24 hours of bacteremia diagnosis despite appropriate therapy
• Mortality for afebrile bacteremia in elderly is 65%, compared to 25-35% in younger patients 6
• Predictors of mortality include pulmonary source, hypotension, and leukocytosis >20,000 cells/mm³ 1

Underlying Pathophysiology

Septic encephalopathy occurs through multiple mechanisms including vascular damage, endothelial activation, blood-brain barrier breakdown, altered brain signaling, brain inflammation, and apoptosis. 5

Importantly, septic encephalopathy may present in early stages of sepsis, even before diagnostic criteria for sepsis can be met, making neurological changes a critical early warning sign. 4, 5

Special Consideration: Dementia Patients

In older adults with underlying dementia, any acute change from baseline mental status should trigger evaluation for sepsis, as the presentation may be even more subtle. 1, 2

The 2024 European Urology guidelines define delirium as disturbance in attention and awareness developing over hours to days, representing an acute change from baseline—this should prompt infectious workup even without fever. 1