Obtaining patient consent is not optional. You must, must, must obtain patient consent.
If the case report patient is deceased, you will need consent from the next of kin. If your case report will include family history, then you need consent from those family members.
ACHE's IRB has a patient consent form. For more information on ACHE's IRB, see Step 3.
In addition to the consent form from ACHE, some journals will require their own consent form. BMJ Case Reports is an example.1 However, the practice of journals requiring there own consent form is not recommended by the Committee on Publication Ethics, so it is not common.2
Here are rules, regulations, and guidance on the protection of research participants, including securing consent: