What is the cause of suspected sepsis (Systemic Inflammatory Response Syndrome) of unknown origin, characterized by fever (hyperthermia) and elevated white blood cell (leukocytosis) and neutrophil (neutrophilia) counts?

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Differential Diagnosis for Sepsis of Unknown Origin

The patient presents with an increasing temperature to 38 degrees and elevated white cell and neutrophil counts, indicating a potential septic process. The following differential diagnoses are considered:

  • Single Most Likely Diagnosis
    • Pneumonia: This is a common cause of sepsis, especially in patients with respiratory symptoms or those who are elderly or immunocompromised. The diagnosis can be confirmed with chest imaging and blood cultures.
  • Other Likely Diagnoses
    • Urinary Tract Infection (UTI): UTIs are a frequent cause of sepsis, particularly in patients with urinary catheters or those who are elderly. Diagnosis can be made with urinalysis and urine culture.
    • Intra-abdominal Infection: Conditions such as cholecystitis, appendicitis, or diverticulitis can lead to sepsis. Imaging studies like CT scans can help identify the source.
    • Skin and Soft Tissue Infections: Severe infections like cellulitis or necrotizing fasciitis can cause sepsis. Clinical examination and imaging can aid in diagnosis.
  • Do Not Miss Diagnoses
    • Meningitis: Although less common, meningitis is a life-threatening condition that requires prompt diagnosis and treatment. Symptoms like headache, stiff neck, and altered mental status should raise suspicion.
    • Endocarditis: Infective endocarditis can present with non-specific symptoms and is a critical diagnosis to consider, especially in patients with a history of heart disease or intravenous drug use.
    • Necrotizing Fasciitis: This is a rapidly progressing infection that can be fatal if not recognized and treated promptly. Patients may present with severe pain, swelling, and skin changes.
  • Rare Diagnoses
    • Lemierre's Syndrome: A rare condition characterized by sepsis and thrombophlebitis of the internal jugular vein, often associated with Fusobacterium necrophorum infection.
    • Toxic Shock Syndrome: A life-threatening condition caused by bacterial toxins, typically associated with Staphylococcus aureus or Streptococcus pyogenes infections.
    • Candidemia: A fungal infection that can cause sepsis, particularly in immunocompromised patients or those with central venous catheters.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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