Klebsiella pneumoniae septic pulmonary embolism from renal vein thrombosis.

OBJECTIVES

To report presumed hypervirulent Klebsiella pneumoniae pyelonephritis causing renal vein-inferior vena cava septic thrombophlebitis, cavitary septic pulmonary emboli, and lung abscesses.

CASE PRESENTATION: A 47-year-old woman with untreated diabetes presented with urinary symptoms, prolonged fever, abdominal pain, and hypoxemia. Blood and urine cultures yielded K. pneumoniae, with bacteremia persisting despite meropenem. An 11-mm positive string test supported a hypermucoviscous phenotype, although hypervirulence was not genetically confirmed. Computed tomography showed left pyelonephritis, renal abscesses, a near-occlusive renal vein-inferior vena cava thrombus, and bilateral peripheral cavitary pulmonary nodules with pulmonary arterial emboli. Transesophageal echocardiography showed no vegetation.

MANAGEMENT AND OUTCOME: Because nephrectomy, thrombectomy, and caval filter placement were considered hazardous, therapy was changed to ceftriaxone at meningitis dosing plus levofloxacin to optimize β-lactam exposure and fluoroquinolone penetration into deep abscesses, with anticoagulation and insulin therapy. Blood cultures cleared by day 7. Pulmonary lesions worsened on day 10, but the thrombus and cavitary lesions regressed by day 38 with continued medical treatment. No recurrent thrombosis was observed on day 207.

CONCLUSION

Persistent K. pneumoniae bacteremia with cavitary peripheral pulmonary nodules should prompt evaluation for an occult septic venous source, particularly, with urinary infection, renal abscesses, diabetes, or negative echocardiography.