II. Indications: Sputum Examination in Community Acquired Pneumonia
- IDSA/ATS recommends Sputum sample obtained for inpatients before Antibiotic therapy
- Absence of Gram Negative Rods and Staphylococcus aureus on a good quality Sputum Culture is reassuring
- Sputum Culture can help direct subsequent Antibiotic therapy narrowing
- IDSA/ATS 2007 indications for Sputum Culture
- ICU Admission
- Failed outpatient Antibiotic therapy
- Cavitary infiltrates
- Active Alcohol Abuse
- Severe COPD
- Pleural Effusion
- Positive Legionella urine Antigen (Legionella culture requires special media)
- Positive Pneumococcal urine Antigen
- Mandell (2007) Clin Infect Dis 44:S27–72 [PubMed]
III. Efficacy
-
Sputum has low diagnostic yield in Community Acquired Pneumonia
- Not recommended in outpatient Community Acquired Pneumonia
- Ewig (2002) Chest 121:1486-92 [PubMed]
IV. Technique: Assessing Sputum Sample Quality
- Ideal Sputum Sample for Culture
- Under 10 squamous epithelial cell per low power field
- Many Neutrophils present (>5 per high power field)
- Bronchial epithelial cells present
- Alveolar Macrophages may be present
- Inadequate Sputum Sample
- Over 25 squamous epithelial cells/LPM
V. Technique: Sputum Sample Preparation
- Pull strand or plug of Sputum onto slide
- Consider buffered crystal violet to stain cells
- Apply cover slip
- View under oil immersion
VI. Approach: Cytology Stains
- No Stain
- Blastomycosis
- Cryptococcosis
-
Gram Stain
- Gram Positive Bacteria
- Candida
- Tuberculosis (weakly Gram Positive)
- Nocardia (weakly Gram Positive)
- Direct Fluorescent Antibody Staining
- Wright stain or Giemsa Stain
- Intracellular organisms
VII. Approach: Special Staining Circumstances
- Acid-fast Mycobacteria (Tuberculosis)
- Ziehl-Neelsen Stain (Red against blue background)
- Kinyoun stain
- Less reliable than Ziehl-Neelsen stain
- Results in quickly stained sample
- Fluorochrome dyes (auramine, rhodamine)
- Higher False Positive Rate than Ziehl-Neelsen stain
- Assist greatly in identifying organisms
- Fungal Organisms
- PAS staining or Methenamine silver staining
- KOH Preparation
VIII. Findings: Microscopic
- Caseous masses
- Dittrich's plugs
- Curschmann's spirals (Asthma)
- Charcot-Leyden Crystals (Asthma)
- Bronchial casts
- Concretions
- Broncholith
- Calcified particles as seen in Broncholithiasis
-
Lung Cancer cells
- Central Bronchus tumors
- May require 4 samples to detect
-
Eosinophils (>5%): identified with Wright's Stain
- Allergy
- Asthma