Overwhelming post-splenectomy infection

Overwhelming post-splenectomy infection (OPSI) is a rare but potentially fatal condition that can occur in individuals who have had their spleen removed (splenectomy) or whose spleen is not functioning properly. The spleen plays a crucial role in the body's defense against bacterial infections, particularly those caused by encapsulated bacteria. Without a functioning spleen, individuals are at increased risk of severe infections.

Etiology

The primary cause of OPSI is the absence or dysfunction of the spleen. The spleen is essential for filtering bacteria from the blood and for promoting the immune response. The most common pathogens responsible for OPSI include Streptococcus pneumoniae, Haemophilus influenzae type b, and Neisseria meningitidis. These bacteria are capable of causing severe infections such as sepsis, meningitis, and pneumonia.

Pathophysiology

Without the spleen's immunological functions, individuals are particularly vulnerable to infections by encapsulated bacteria. The spleen's role in producing opsonizing antibodies, which mark pathogens for destruction, is critical. In the absence of these antibodies, the body's ability to clear these pathogens is significantly reduced, leading to an increased risk of overwhelming infection.

Clinical Presentation

Symptoms of OPSI can develop rapidly and may include fever, chills, low blood pressure (hypotension), rapid heart rate (tachycardia), confusion, and signs of sepsis. Due to the rapid progression of the condition, prompt medical attention is crucial.

Diagnosis

Diagnosis of OPSI is based on the clinical presentation and history of splenectomy or splenic dysfunction. Laboratory tests may show signs of infection, and blood cultures can identify the causative organism. Imaging studies are not typically diagnostic but may be used to rule out other conditions.

Prevention

Preventive measures are key to reducing the risk of OPSI. Vaccinations against S. pneumoniae, H. influenzae type b, and N. meningitidis are recommended for individuals before or after splenectomy. Prophylactic antibiotics may also be prescribed for certain individuals to prevent infection.

Treatment

Treatment of OPSI requires prompt administration of broad-spectrum antibiotics to cover the likely pathogens. Once the specific causative organism is identified, antibiotic therapy can be adjusted accordingly. Supportive care, including fluids and vasopressors, may be necessary to manage sepsis and maintain blood pressure.

Prognosis

The prognosis of OPSI can vary but is generally poor without rapid treatment. Early recognition and treatment are critical for survival. With appropriate preventive measures, the risk of OPSI can be significantly reduced.

See Also

• Splenectomy
• Sepsis
• Pneumonia
• Meningitis

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