From the Guidelines
When approaching a patient with fever and altered mental status, immediate medical attention is crucial, and a comprehensive approach including empiric treatment with broad-spectrum antibiotics and antivirals, diagnostic workup, and supportive care is essential to maximize the chances of a positive outcome. Begin with a rapid assessment of vital signs and neurological status. Perform a thorough physical examination, including signs of meningeal irritation.
- Initiate empiric treatment with broad-spectrum antibiotics (e.g., ceftriaxone 2g IV every 12 hours) and antivirals (e.g., acyclovir 10 mg/kg IV every 8 hours) to cover potential bacterial meningitis and herpes encephalitis, respectively, as recommended by the Infectious Diseases Society of America 1.
- Concurrently, order urgent laboratory tests including complete blood count, electrolytes, blood glucose, liver and renal function tests, blood cultures, and arterial blood gases.
- Obtain neuroimaging (preferably MRI, or CT if MRI is unavailable) to rule out structural abnormalities or signs of increased intracranial pressure.
- If there are no contraindications, perform a lumbar puncture for CSF analysis, which is a crucial step in diagnosing encephalitis and other CNS infections 1. Manage the fever with acetaminophen (1000 mg every 6 hours) or ibuprofen (400 mg every 6 hours) and provide supportive care including fluid management and respiratory support if needed.
- Monitor the patient closely in an intensive care setting, as the altered mental status may be due to the fever itself or indicate a serious central nervous system infection or metabolic derangement, hence the importance of a comprehensive and rapid approach. It is also essential to identify and treat alternative causes of altered mental status, as well as precipitating factors, as recommended by the American Association for the Study of Liver Diseases and the European Association for the Study of the Liver 2.
- A four-pronged approach to management, including initiation of care, identification of precipitating factors, commencement of empirical treatment, and treatment of alternative causes, is crucial in patients with altered consciousness 2.
From the Research
Approach to a Patient with Fever and Altered Mental Status (AMS)
The approach to a patient with fever and altered mental status (AMS) involves a structured assessment to identify the underlying cause of the symptoms.
- A focused history and physical assessment can help differentiate between structural or medical causes 3.
- Asymmetrical neurological findings, such as a dilated and fixed pupil, dysconjugated extraocular movements, and asymmetrical motor findings, suggest brainstem dysfunction due to a structural lesion, while symmetrical neurological findings usually indicate a medical disorder 3.
- The Glasgow Coma Score (GCS) can be used to predict the outcome of patients with fever and altered sensorium, with lower GCS scores associated with a higher risk of poor outcomes 4.
Common Causes of Fever and Altered Mental Status
The common causes of fever and altered mental status include:
- Infections such as pneumonia, urinary tract infection, meningitis, and typhoid fever 3
- Structural neurological causes such as cerebral vasculature accidents (CVA) and hypoxic ischemic brain injury 5
- Medical causes such as hepatic encephalopathy, hypoglycemia, and hyponatremia 5
Evaluation and Management
The evaluation and management of a patient with fever and altered mental status involve:
- A thorough history and physical examination to identify potential causes 3, 5
- Laboratory investigations such as blood tests and imaging studies (e.g., brain MRI) to confirm the diagnosis 5, 4
- Prompt treatment of the underlying cause to improve patient outcomes 6, 7
- Consideration of less common etiologies such as cerebral fat embolism, blunt carotid artery injury, and vertebrobasilar artery thrombosis in non-head injured trauma patients 7