Acute brain syndrome

Overview

Acute brain syndrome (ABS), also known as acute organic brain syndrome or simply delirium, is a sudden onset of brain dysfunction that results in confusion, disorientation, memory issues, and changes in consciousness. Unlike chronic brain conditions like dementia, ABS develops rapidly, often over hours or days, and is usually caused by an underlying medical issue or toxic exposure. It is considered a medical emergency that requires immediate evaluation and management to prevent permanent cognitive damage or death.

Causes

Acute brain syndrome can result from a wide range of underlying conditions that temporarily impair brain function. Common causes include:

• Infections: Such as urinary tract infections, pneumonia, or meningitis

• Metabolic imbalances: Electrolyte disturbances, hypoglycemia, or liver/kidney failure

• Substance use or withdrawal: Alcohol, sedatives, or recreational drugs

• Medications: Anticholinergics, opioids, or drug interactions

• Hypoxia: Reduced oxygen delivery to the brain

• Trauma or surgery: Especially in older adults

• Sepsis or systemic illness

• Dehydration or malnutrition

Symptoms

The hallmark of acute brain syndrome is a sudden change in mental status. Common signs and symptoms include:

• Disorientation: Confusion about time, place, or identity

• Memory disturbances: Especially short-term memory loss

• Fluctuating levels of consciousness: Ranging from hyper-alertness to drowsiness

• Hallucinations or delusions: Often visual or paranoid in nature

• Agitation or restlessness

• Sleep-wake cycle disruption

• Difficulty concentrating or following commands

• Slurred speech or incoherence

Symptoms often fluctuate throughout the day, and episodes may worsen in the evening (known as “sundowning”).

Diagnosis

Diagnosis of acute brain syndrome is clinical and requires a careful assessment of the patient’s history, current symptoms, and potential underlying causes. Key steps include:

• Clinical assessment: Using tools like the Confusion Assessment Method (CAM)

• Neurological examination: To rule out stroke or other primary brain disorders

• Blood tests: To evaluate metabolic function, infection, and drug levels

• Imaging studies: CT or MRI of the brain if head trauma, stroke, or tumor is suspected

• Electroencephalogram (EEG): May show generalized slowing in delirium

• Review of medications and toxicology screen

It’s important to distinguish ABS from psychiatric conditions and chronic cognitive disorders like Alzheimer’s disease.

Treatment

Treatment focuses on addressing the underlying cause and supporting the patient’s recovery. Key management strategies include:

• Identify and treat the underlying cause: e.g., antibiotics for infection, fluids for dehydration, or oxygen for hypoxia

• Medication review: Discontinue or adjust any offending drugs

• Supportive care: Reorientation, calm environment, adequate hydration and nutrition

• Behavioral management: Use of non-pharmacologic strategies to reduce agitation

• Pharmacologic treatment: Antipsychotics (like haloperidol or quetiapine) may be used short-term for severe agitation or hallucinations, with caution

Patients often require hospitalization and close monitoring, particularly if they are at risk of harming themselves or others.

Prognosis

The prognosis of acute brain syndrome depends on the severity of the underlying cause and how quickly it is treated. In many cases, especially with prompt intervention, symptoms resolve within days to weeks. However, in elderly or medically fragile patients, recovery may be slower, and there is a higher risk of long-term cognitive impairment or recurrence.

Untreated or prolonged delirium can lead to permanent brain damage, increased risk of falls, longer hospital stays, and higher mortality. Early recognition and intervention significantly improve outcomes.