What is the most likely cause of encephalopathy in a patient with diabetic ketoacidosis (DKA) and a history of significant alcohol use?

Hepatic Encephalopathy is the Most Likely Diagnosis

The presence of asterixis (finger fluttering with wrist extension) in a patient with significant chronic alcohol use (a fifth of vodka daily) strongly indicates hepatic encephalopathy, despite the concurrent DKA. 1

Clinical Reasoning

Key Diagnostic Feature: Asterixis

• Asterixis is the pathognomonic sign of hepatic encephalopathy, characterized by repetitive fluttering of fingers when wrists are extended with arms outstretched 1
• This specific neurological finding is not associated with diabetic coma, hypertensive emergency, or sepsis in this clinical context 1

Why Not the Other Options?

Diabetic Coma (Option B) is unlikely because:

• His glucose is controlled at 168 mg/dl, which is near target range during DKA recovery 1
• Mental status changes from DKA typically present with lethargy progressing to coma when glucose is markedly elevated (>250 mg/dl for DKA) 1
• DKA-related encephalopathy does not produce asterixis 2, 3
• The patient is following simple commands, inconsistent with diabetic coma 1

Hypertensive Emergency (Option C) is ruled out:

• BP of 136/72 is not in the hypertensive emergency range (typically >180/120 mmHg with end-organ damage)
• No focal neurological deficits or papilledema mentioned 1

Sepsis (Option D) is less likely:

• Patient is afebrile (36.4°C) with stable vital signs (HR 70, RR 16, BP 136/72) 1
• While infection is the most common precipitating factor for DKA, the clinical picture here points more specifically to hepatic encephalopathy 1

Critical Diagnostic Approach

Hepatic Encephalopathy as Diagnosis of Exclusion

• The AASLD guidelines emphasize that hepatic encephalopathy is a diagnosis of exclusion in patients with altered mental status 1
• Alcohol intoxication and withdrawal remain common causes of altered mental status in chronic alcohol users 1
• Multiple conditions can coexist and synergize to worsen mental status 1

Essential Workup Required

• Investigation should include metabolic laboratory assessment, drug and alcohol levels, and ammonia level 1
• A low ammonia level would point toward etiologies other than hepatic encephalopathy 1
• Routine investigations should assess for alcohol withdrawal, electrolyte disorders, and other metabolic causes 1

Important Clinical Pitfalls

Common Mistake: Attributing all encephalopathy in a DKA patient to the diabetes alone 1

• The significant alcohol history (fifth of vodka daily) suggests underlying cirrhosis or acute liver injury 1
• Alcohol abuse is specifically listed as a precipitating factor for DKA, meaning both conditions likely coexist 1

Key Caveat: Multiple causes can be present simultaneously 1

• This patient may have both resolving DKA and hepatic encephalopathy
• The presence of asterixis specifically points to hepatic rather than diabetic etiology 1

Management Implications

• Empiric therapy for suspected hepatic encephalopathy should include lactulose (orally or rectally) 1
• Continue monitoring and treating the DKA appropriately 1
• Consider dexmedetomidine over benzodiazepines if sedation needed, as it can reduce the need for benzodiazepines in alcohol withdrawal 1
• Thiamine supplementation is critical given the chronic alcohol use history 4, 5