Criteria for Hospital Admission in Pneumonia
Use CURB-65 score ≥2 or PSI class IV-V to identify patients requiring hospitalization, but always supplement these objective scores with clinical judgment regarding ability to take oral medications, social support, and presence of complications. 1
Primary Severity Assessment Tools
CURB-65 Score (recommended for ease of use):
- Confusion (new onset)
- Urea >7 mmol/L (>19.1 mg/dL)
- Respiratory rate ≥30 breaths/min
- Blood pressure: systolic <90 or diastolic ≤60 mmHg
- Age ≥65 years
Hospitalization thresholds:
- Score 0-1: Outpatient treatment (mortality 0.7-2.1%) 1
- Score ≥2: Hospitalization or intensive home care warranted (mortality 9.2-40%) 1, 2
The CURB-65 system is preferred over PSI because it directly measures illness severity rather than just mortality risk, and patients with scores ≥2 typically have clinically important physiologic derangements requiring active intervention. 1
Critical Subjective Factors That Override Low Scores
Even patients with low severity scores (CURB-65 0-1 or PSI class I-III) require admission if any of the following are present:
Respiratory complications:
Hemodynamic instability:
Pneumonia complications:
Inability to maintain oral intake or medications 1, 3
Decompensated comorbidities:
- Exacerbation of COPD, heart failure, or diabetes requiring hospitalization 1
Social factors:
- No reliable caregiver available 1
- Homelessness, severe psychiatric illness, or injection drug abuse 1
- Poor functional status or cognitive dysfunction 1
Treatment failure:
Approximately 60% of low-risk patients who are hospitalized have at least one of these additional factors. 1
ICU Admission Criteria
Direct ICU admission is mandatory for patients meeting either major criterion:
Major criteria (presence of ONE requires ICU):
- Septic shock requiring vasopressors 1, 2
- Acute respiratory failure requiring intubation and mechanical ventilation 1, 2
Minor criteria (presence of THREE OR MORE requires ICU or high-level monitoring unit):
- Respiratory rate >30 breaths/min 1
- PaO₂/FiO₂ ratio <250 1
- Multilobar infiltrates 1
- Confusion 1
- Blood urea nitrogen ≥20 mg/dL 1
- Leukopenia (WBC <4,000 cells/mm³) due to infection 1
- Thrombocytopenia (platelets <100,000/mm³) 1
- Hypothermia (core temperature <36°C) 1
- Hypotension requiring aggressive fluid resuscitation 1
These IDSA/ATS 2007 criteria have been prospectively validated with an area under the curve of 0.85 for predicting need for mechanical ventilation or vasopressor support. 4
Critical Pitfalls to Avoid
Never rely solely on severity scores without clinical assessment. Studies demonstrate that patients with low PSI or CURB-65 scores sometimes require ICU admission, and delayed ICU transfer is associated with increased mortality. 1
Young, previously healthy patients can be severely ill despite low scores. A 25-year-old with severe hypotension and tachycardia would score PSI class II but clearly requires hospitalization. 1
Dynamic assessment over several hours is more accurate than single time-point scoring, as vital signs and laboratory values may represent transient abnormalities. 1
Up to 45% of patients ultimately requiring ICU care are initially admitted to general wards, representing missed opportunities for early intervention. 1
Implementation Requirements
First antibiotic dose must be administered within 8 hours of hospital arrival (ideally in the emergency department for admitted patients). 2, 5 Delays in appropriate antibiotic therapy significantly increase mortality, particularly in PSI class IV-V patients. 1
When in doubt, hospitalize. The consequences of undertreating severe pneumonia far outweigh the costs of brief observation for stable patients. 2