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Last updated: September 24, 2025View editorial policy

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Differential Diagnosis for Rigors

Rigors are a symptom characterized by intense shivering or shaking, often accompanied by a fever. The following differential diagnosis is organized into categories to help guide the diagnostic process.

  • Single Most Likely Diagnosis
    • Urinary Tract Infection (UTI): A common cause of rigors, especially in older adults or those with underlying medical conditions. UTIs can lead to bacteremia, which may cause rigors.
  • Other Likely Diagnoses
    • Pneumonia: Both community-acquired and hospital-acquired pneumonia can cause rigors, especially if the infection is severe or caused by a virulent pathogen.
    • Sepsis: A systemic infection that can cause rigors, along with other symptoms such as fever, tachycardia, and hypotension.
    • Malaria: In areas where malaria is endemic, it is a common cause of rigors, especially in travelers or individuals who have not taken prophylactic measures.
    • Influenza: Certain strains of influenza can cause rigors, especially during the initial stages of the illness.
  • Do Not Miss Diagnoses
    • Endocarditis: Although less common, endocarditis is a serious condition that can cause rigors, along with other symptoms such as fever, heart murmur, and embolic phenomena.
    • Meningitis: Bacterial meningitis can cause rigors, along with other symptoms such as headache, stiff neck, and altered mental status.
    • Severe Bacterial Infections (e.g., septic arthritis, osteomyelitis): These infections can cause rigors, along with other symptoms such as localized pain, swelling, and redness.
  • Rare Diagnoses
    • Brucellosis: A zoonotic infection that can cause rigors, along with other symptoms such as fever, fatigue, and weight loss.
    • Lymphoma: Certain types of lymphoma can cause rigors, along with other symptoms such as fever, night sweats, and weight loss.
    • Drug Fever: Certain medications can cause rigors, along with other symptoms such as fever and rash.

Each of these diagnoses has a unique set of clinical features and risk factors that can help guide the diagnostic process. A thorough history, physical examination, and laboratory tests are essential to determine the underlying cause of rigors.

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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