Differential Diagnosis

The patient's presentation suggests a complex interplay of her liver disease, alcohol use disorder, and potential nutritional deficiencies. Here's a breakdown of the differential diagnosis:

• Single most likely diagnosis:

  • Alcoholic Neuropathy with Vitamin B12 Deficiency: The patient's long history of alcohol use disorder, combined with symptoms of neuropathy (lack of sensation to touch, pain, temperature, and vibration in both feet and hands) and the presence of hyperpigmented patches, suggests alcoholic neuropathy. The increased MCV (mean corpuscular volume) and elevated serum homocysteine with normal serum methylmalonate levels support a diagnosis of vitamin B12 deficiency, which is common in alcoholics due to poor dietary intake and impaired absorption.

• Other Likely diagnoses:

  • Liver Disease-related Neuropathy: The patient's liver cirrhosis could contribute to her neuropathic symptoms, possibly through a combination of nutritional deficiencies and the toxic effects of liver dysfunction on the nervous system.
  • Diabetic Neuropathy: Given her history of type 2 diabetes mellitus, diabetic neuropathy is a likely contributor to her symptoms, especially the lack of sensation in her feet and hands.
  • Wernicke-Korsakoff Syndrome: Although her confusion and impaired memory have not resolved, this could be a sequela of Wernicke's encephalopathy, which is associated with thiamine deficiency, commonly seen in alcoholics.

• Do Not Miss diagnoses:

  • Subacute Combined Degeneration (Vitamin B12 Deficiency): While the patient's symptoms and lab values suggest vitamin B12 deficiency, it's crucial not to miss this diagnosis due to its potential for severe and irreversible neurological damage if left untreated.
  • Thiamine Deficiency: Given the patient's alcohol use disorder, thiamine deficiency is a critical diagnosis not to miss, as it can lead to Wernicke-Korsakoff syndrome, which has significant morbidity and mortality if not promptly treated.

• Rare diagnoses:

  • Porphyria: The hyperpigmented patches could suggest a diagnosis of porphyria cutanea tarda, a disorder of heme biosynthesis that can be associated with liver disease and alcohol use. However, this would be less likely and requires specific diagnostic testing.
  • Amyloidosis: Although rare, amyloidosis could present with neuropathy and skin changes, but it would be an uncommon diagnosis in this context and requires further investigation, including biopsy.