Differential Diagnosis for Fevers, Sweats, and High CRP after Surgery or Heart Cath

Single Most Likely Diagnosis

• Postoperative Inflammatory Response: This is a common reaction to surgical stress, which can cause an increase in inflammatory markers like CRP, fever, and sweats without an infectious cause. The body's response to tissue injury and the surgical procedure itself can lead to a systemic inflammatory response.

Other Likely Diagnoses

• Atypical or Viral Infections: Infections that are not bacterial in nature, such as viral infections, can present with fever, sweats, and elevated CRP without the typical signs of bacterial infection.
• Drug Reactions: Certain medications, including those used during or after surgery, can cause an allergic or hypersensitivity reaction leading to fever, sweats, and elevated inflammatory markers.
• Thromboembolic Events: Conditions like deep vein thrombosis (DVT) or pulmonary embolism (PE) can cause fever and elevated CRP, especially in the postoperative period.
• Adrenal Insufficiency: This condition, particularly if the patient has a history of steroid use, can lead to a stress response that includes fever and elevated inflammatory markers due to the body's inability to produce adequate cortisol.

Do Not Miss Diagnoses

• Pulmonary Embolism (PE): Although mentioned under other likely diagnoses, it's crucial to emphasize PE as a "do not miss" diagnosis due to its high mortality rate if not promptly treated.
• Myocardial Infarction: Especially after heart catheterization, myocardial infarction can present atypically with fever and elevated inflammatory markers.
• Aortic Dissection: A life-threatening condition that can occur after heart catheterization or surgery, presenting with severe pain and potentially fever and elevated CRP.

Rare Diagnoses

• Serotonin Syndrome: A rare but potentially life-threatening condition caused by certain medications, leading to fever, sweats, and elevated inflammatory markers among other symptoms.
• Neuroleptic Malignant Syndrome (NMS): Another rare but dangerous condition associated with certain psychiatric medications, characterized by fever, muscle rigidity, and altered mental status.
• Malignant Hyperthermia: A rare, life-threatening medical emergency triggered by certain drugs used in general anesthesia, leading to fever, muscle rigidity, and other systemic symptoms.