In both primary and secondary Parkinson, dopaminergic neurons located in the substantia nigra of the corpus striatum are destroyed so there the same symptoms are present.
In primary Parkinson (Parkinson disease) the reason for progressive dying of those neurons is unknown. One of the possible hypothesis is that those neurons normally dies with aging but some people are born with less dopaminergic neurons in the substantia nigra so when they become older they are missing those neurons more than the rest of the normal people.
In secondary Parkinson (Parkinson syndrome) dopaminergic neurons in the substantia nigra can be destroyed by various known reasons like brain infection, cerebro-vascular insult (stroke), cerebral atherosclerosis, brain trauma, poisoning with heavy metals or pesticides etc. Beside Parkinson symptoms there can be also present some other symptoms typical for the primary disorder. For example, high temperature in brain infection.