Hypoglycemia or Hyperglycemia: Given the patient's history of diabetes and the blood glucose level (BGL) of 190, which is elevated but not extremely high, and considering the patient's altered mental status, it's crucial to assess if the patient's diabetes management is adequate. However, the presence of dementia and the current BGL might suggest that the altered mental status could be attributed to other factors as well, but diabetes-related complications should be a primary consideration.

Infection (e.g., Urinary Tract Infection, Pneumonia): Infections are common in elderly patients and can cause altered mental status. The patient's history and current presentation (altered mental status, cold to the touch but with a normal oral temperature) could be indicative of a systemic infection.
Dehydration: Elderly patients, especially those with dementia, are at risk for dehydration, which can lead to altered mental status. The patient's history of diabetes and possibly inadequate fluid intake could contribute to dehydration.
Cardiovascular Events (e.g., Stroke, Myocardial Infarction): Given the patient's age and the presence of risk factors like diabetes and hypertension (BP 160/80), cardiovascular events should be considered, especially if there are focal neurological deficits or other suggestive symptoms.

Sepsis: Although the patient's temperature is 97°F, which is slightly below normal, sepsis can present atypically in the elderly, with hypothermia being a possibility. The altered mental status and potential for an underlying infection make sepsis a critical diagnosis not to miss.
Hypothyroidism: This condition can cause altered mental status, especially in the elderly. Given the patient's coldness to the touch, despite a normal oral temperature, hypothyroidism should be considered.
Medication Overdose or Adverse Effects: The patient's current medication regimen could be contributing to the altered mental status, either through overdose or adverse effects, especially considering the patient's age and potential for polypharmacy.

Wernicke's Encephalopathy: Although rare, this condition, caused by thiamine deficiency, can lead to altered mental status and is particularly important to consider in patients with a history of alcohol abuse or malnutrition.
Hyperosmolar Hyperglycemic State (HHS): While the patient's BGL is elevated, it's not indicative of HHS on its own. However, in diabetic patients, especially with altered mental status, HHS is a rare but critical diagnosis to consider, especially if there are signs of severe dehydration.