In a 6-qt slow cooker, whisk together Old Bay seasoning, lemon juice, hot sauce and 6 cups water.
Add in potatoes, onion, garlic and bay leaves into the slow cooker. Cover and cook on low heat for 3-4 hours, or until potatoes are almost tender.
Stir in sausage and corn; cover and cook on high heat for 30 minutes.
Stir in shrimp. Cover and cook on high heat, stirring twice, until shrimp are opaque and pink, about 20-30 minutes.
Serve immediately, garnished with parsley, if desired.