Differential Diagnosis
Given the symptoms started after 1 week and persisted, we can consider the following differential diagnoses, categorized for clarity:
- Single Most Likely Diagnosis
- Viral infection: This is a common cause of symptoms that start after a week and persist. Many viral infections have an incubation period of about a week before symptoms appear and can last for several weeks.
- Other Likely Diagnoses
- Bacterial infection: Some bacterial infections can have a delayed onset of symptoms and persist if not treated properly.
- Allergic reaction: An allergic reaction could start after exposure to a new allergen and persist until the allergen is removed or treated.
- Inflammatory condition: Conditions like arthritis or inflammatory bowel disease can have a delayed onset and persist without treatment.
- Do Not Miss Diagnoses
- Appendicitis: Although it typically presents acutely, some cases can have a more gradual onset and persist, making it crucial not to miss this diagnosis due to its potential for severe complications.
- Meningitis: This is a serious infection that can present with a variety of symptoms, including fever, headache, and stiff neck, and requires immediate medical attention.
- Sepsis: A systemic infection that can start with nonspecific symptoms but can rapidly progress to a life-threatening condition.
- Rare Diagnoses
- Autoimmune disorders: Conditions like lupus or rheumatoid arthritis can have a wide range of symptoms and may start with a gradual onset.
- Endocrine disorders: Certain endocrine conditions, such as thyroiditis or adrenal insufficiency, can have nonspecific symptoms that persist.
- Neoplastic conditions: Although rare, some cancers can present with persistent, nonspecific symptoms.
Each of these diagnoses has a brief justification based on the timing and persistence of symptoms. The key to narrowing down the differential diagnosis is obtaining a detailed history, performing a thorough physical examination, and ordering appropriate diagnostic tests.