It means sticking with.<br />
I was consistent in not not having a headache.
URBAN DICTIONARY: consistant : A slang word referring to the never ending worth of something. In other words, an adjective meaning "cool", "awesome", or "great" but implying a long-lasting quality. This word began to be used in modern slang in the south-eastern United States in the summer of 2011, predominantly among middle-class African Americans.<br />
*Full back makes a nice block* <br />
Hell yeah! That's where it's at! A consistent block!"<br />
*Two young adults to each other* <br />
"Hey doo, you STILL working that job?" <br />
"**** mane, yeah. Boss a *****-***, but the pay is consistent as hell mane."
In this context, consistent is being used as a comparative, in order to relate a ymptom with a cause. It associates things that are suppositions by implying there is plenty of precedent to make such an assumption. Often similar uses of the word can be used to illustrate a similarity, usually implying a level of similarity close to calling it congruent.
"I am consistent with your mother"<br />
meaning your mother is a h0 with huge@ss t!ts
I'm the perverted pope! You shall be beheaded for blasphemy!
Consistant means something having the same effect every time it is applied.
Sounds like the pathologist came up with an answer that was satisfactory as a cause of the results it may not have been the actual cause. Not being a pathologist I would not know.