latent, dormant, quiescent, potential mean not now showing signs of activity or existence. latent applies to a power or quality that has not yet come forth but may emerge and develop. dormant suggests the inactivity of something (as a feeling or power) as though sleeping.
However, H1N1 can progress quickly, so it is uncertain if knowing the patient had influenza would have prevented their rapid progression. Vasopressors can cause tissue ischemia if used in high doses, and I have seen necrosis of digits due to vasopressors. That being said, I have never seen limb amputations due to vasopressor use, but it could happen.
Vasopressors are compounds that cause the blood vessels to constrict, which, in turn, causes blood pressure to rise. A number of compounds can have this effect, ranging from pharmaceuticals that are used on patients in certain situations to recreational drugs that have a vasoconstrictive effect.