What is the most likely cause of encephalopathy in a patient with a history of chronic alcohol use, frequent falls, scalp swelling, lethargy, disorientation, and focal neurologic signs?

Traumatic Subdural Hematoma

The most likely cause of encephalopathy in this patient is a traumatic subdural hematoma, given his chronic alcohol use with frequent falls, scalp swelling indicating recent head trauma, altered mental status, and focal neurologic findings (left Babinski sign). 1

Clinical Reasoning

Why Subdural Hematoma is Most Likely

• Chronic alcoholics with frequent falls are at extremely high risk for subdural hematomas due to cerebral atrophy creating a larger subdural space and increased vulnerability of bridging veins 1
• The scalp swelling directly indicates recent head trauma, and the patient was "found down" with unknown mechanism of injury 1
• Subdural hematomas are specifically highlighted in hepatic encephalopathy guidelines as critical alternative diagnoses that must be excluded in alcoholic patients with altered mental status 1
• The focal neurologic sign (left Babinski) indicates structural brain pathology rather than diffuse metabolic encephalopathy, pointing toward a mass lesion with lateralizing features 1
• The subacute presentation over "several days" is classic for chronic subdural hematoma, which can present with progressive encephalopathy rather than acute deterioration 1

Why Other Options Are Less Likely

Hepatic encephalopathy alone would not explain:

• The focal Babinski sign (hepatic encephalopathy causes symmetric neurologic findings) 1
• The scalp swelling from trauma 1
• Guidelines explicitly state that subdural hematoma must be ruled out before attributing symptoms to hepatic encephalopathy 1

Wernicke's encephalopathy is certainly possible given chronic alcohol use and ataxia, but:

• The classic triad (ophthalmoplegia, ataxia, confusion) is present in only 10-16% of cases 2, 3, 4, 5
• Wernicke's typically causes symmetric neurologic findings, not focal signs like a unilateral Babinski 3, 4
• However, Wernicke's may coexist with subdural hematoma and should be treated empirically 2, 3, 6

Epidural hematoma requires high-impact trauma and typically presents acutely with rapid deterioration, not a subacute course over days 1

Obstructive hydrocephalus would not explain the scalp trauma or focal Babinski sign 1

Basilar skull fracture would show specific signs (Battle's sign, raccoon eyes, CSF rhinorrhea/otorrhea) not mentioned here 1

Critical Diagnostic Approach

Immediate Imaging Required

• Brain CT without contrast is the first-line imaging study to identify subdural hematoma, which appears as a crescent-shaped hyperdense (acute) or hypodense (chronic) collection 1
• Do not delay imaging while pursuing other diagnostic workup in a patient with altered mental status and focal neurologic signs 1

Concurrent Thiamine Administration

• Give thiamine 500 mg IV three times daily immediately, before any glucose-containing fluids, to prevent or treat coexisting Wernicke's encephalopathy 2, 3, 6
• All patients with chronic alcohol use and altered mental status should receive prophylactic thiamine regardless of whether classic Wernicke's triad is present 2, 3, 6, 4
• Thiamine deficiency is present in 11-55% of hospitalized alcoholics and is frequently missed clinically 4, 5

Additional Differential Considerations in Alcoholics

• Check ammonia level, electrolytes (especially sodium), glucose, and infection markers as hepatic encephalopathy precipitants 1
• Consider EEG if encephalopathy persists after structural lesions are excluded, as non-convulsive status epilepticus (SESA syndrome) can mimic encephalopathy in chronic alcoholics 7, 8, 9

Common Pitfalls to Avoid

• Attributing all encephalopathy to hepatic causes in cirrhotic patients without neuroimaging - 22% of patients with liver disease suspected of having hepatic encephalopathy have alternative diagnoses including subdural hematoma 1
• Missing subdural hematoma because it can present subacutely with fluctuating mental status rather than acute coma 1
• Failing to give empiric thiamine to all alcoholic patients with altered mental status - neurologic signs are absent in most cases of Wernicke's encephalopathy 2, 3, 4, 5
• Administering glucose before thiamine, which can precipitate or worsen Wernicke's encephalopathy 2, 3, 6
• Overlooking that multiple conditions often coexist in alcoholic patients (subdural hematoma + Wernicke's + hepatic encephalopathy) 1, 3