Differential Diagnosis for Fever, Cough, Expectoration, and Altered Behavior
Single Most Likely Diagnosis
- Tuberculosis (TB): A month-long history of fever, cough, and expectoration suggests a chronic infection like TB. Altered behavior for 3 days could indicate the onset of TB meningitis or a severe systemic infection affecting the central nervous system.
Other Likely Diagnoses
- Pneumonia: Bacterial pneumonia can cause prolonged fever, cough, and expectoration. Altered behavior could result from severe infection, hypoxia, or sepsis.
- Chronic Bronchitis: This condition can lead to persistent cough and expectoration. Altered behavior might be due to hypoxia or a secondary infection.
- Influenza or Other Viral Infections: Although less common for such a prolonged period, some viral infections can cause persistent respiratory symptoms. Altered behavior could be due to encephalitis or severe systemic illness.
Do Not Miss Diagnoses
- Meningitis or Encephalitis: These are life-threatening conditions that can present with altered behavior. Even if less likely, they must be considered due to their high mortality and morbidity if missed.
- Sepsis: Any severe infection can lead to sepsis, which is a medical emergency. Altered behavior can be an early sign of sepsis, especially in the elderly or those with compromised immune systems.
- Brain Abscess: A rare but potentially deadly condition that can arise from a chronic infection like sinusitis or otitis media, spreading to the brain.
Rare Diagnoses
- Lung Abscess: Although rare, a lung abscess can cause prolonged fever, cough, and expectoration. Altered behavior could be due to sepsis or the spread of infection to the brain.
- Q Fever: A zoonotic disease caused by Coxiella burnetii, which can lead to chronic infection and neurological manifestations in rare cases.
- Cystic Fibrosis: A genetic disorder leading to chronic respiratory infections. While not typically presenting with altered behavior acutely, it could be a consideration in younger patients with a history of recurrent infections.
- Histoplasmosis: A fungal infection that can cause chronic respiratory symptoms and, in rare cases, central nervous system involvement.