Differential Diagnosis for Fatigue, Headache, No Fever, Neck Stiffness, and Muscle Aches
- Single Most Likely Diagnosis
- Viral Meningitis: This condition is characterized by inflammation of the meninges (the protective membranes covering the brain and spinal cord) due to a viral infection. The symptoms of viral meningitis can include fatigue, headache, neck stiffness, and muscle aches, which align with the patient's presentation. The absence of fever does not rule out this diagnosis, as not all patients with viral meningitis present with fever.
- Other Likely Diagnoses
- Tension Headache: This is a common type of headache that can cause fatigue, headache, and muscle aches. While it typically does not cause neck stiffness, some patients may experience mild neck discomfort.
- Migraine: Migraines can cause severe headaches, fatigue, and muscle aches. Some patients may also experience neck stiffness or discomfort during a migraine episode.
- Post-Viral Syndrome: This condition occurs after a viral illness and can cause prolonged fatigue, headache, and muscle aches. The absence of fever and the duration of symptoms (6 days) could suggest a post-viral syndrome.
- Do Not Miss Diagnoses
- Bacterial Meningitis: Although less likely due to the absence of fever, bacterial meningitis is a medical emergency that requires prompt diagnosis and treatment. It can present with headache, neck stiffness, and fatigue, among other symptoms.
- Subarachnoid Hemorrhage: This is a life-threatening condition caused by bleeding into the space surrounding the brain. It can present with sudden, severe headache (often described as "the worst headache of my life"), neck stiffness, and sometimes fatigue.
- Encephalitis: Inflammation of the brain tissue, usually due to a viral infection, which can cause fever (although not always present), headache, neck stiffness, and altered mental status.
- Rare Diagnoses
- Lyme Meningitis: Caused by the bacterium Borrelia burgdorferi, transmitted by tick bites. It can cause symptoms similar to viral meningitis, including headache, neck stiffness, and fatigue, especially in endemic areas.
- West Nile Virus: A viral infection transmitted by mosquitoes, which can cause meningitis or encephalitis, presenting with symptoms such as headache, fever (not always present), neck stiffness, and muscle aches.
- Chronic Fatigue Syndrome: A condition characterized by extreme fatigue that cannot be explained by any underlying medical condition. While it's a diagnosis of exclusion, it's essential to consider in patients with prolonged fatigue without an apparent cause.