Rusty sputum

Specialty: Respiratory.

• rusty expectoration
• rust-colored sputum

Why it occurs

• Lobar pneumonia due to Streptococcus pneumoniae (pneumococcus) (the reddish-brownish or rusty color is due to the lysis of erythrocytes within the alveoli during the red hepatization phase of the lung lobe)
• Segmental pulmonary infarction secondary to embolism (necrosis of lung tissue with old alveolar bleeding and degradation of hemoglobin to hemosiderin)
• Pulmonary paragonimiasis (parasitic infection with Paragonimus westermani that causes lung cavities with chronic rusty sputum containing eggs of the parasite)
• Silicosis complicated with progressive massive fibrosis (melanophthisis or dark/rusty expectoration due to destruction of silicotic nodules loaded with dust and histiocytes)
• Severe influenza bronchitis with diffuse microbleeds of the bronchial mucosa

Initial workup

Gram stain and quantitative culture of good quality sputum (<10 epithelial cells and >25 leukocytes per low power field); Anteroposterior and lateral chest x-ray; Serial blood cultures (two doses); Blood analysis with leukocyte count and procalcitonin levels; Detection of pneumococcus antigen in urine.

Standard management

• Ceftriaxone — 1-2 g intravenously or intramuscularly every 24 hours, as empirical antibiotic treatment of choice for pneumococcal pneumonia
• Amoxicillin — 1 g orally every 8 hours if outpatient management is decided for the patient with low risk of complications
• Paracetamol (500-1000 mg orally every 6-8 hours to control fever and associated chest pain).