Are meniere's disease and endolymphatic hydrops the same condition?

Yes. Their symptoms are the same (episodic vertigo, fluctuating hearing loss, tinnitus and fullness of the ear). Endolymphatic hydrops is most frequently described as a disorder of increased pressure within the inner ear and has many known etiologies or causes. The term meniere's disease should only be applied in cases where the cause is idiopathic or not known.