A friend's brother passed away suddenly (within 4 hours) and the autopsy
revealed no cause of death.

The death summary stated:
       "He was well until a few hours prior to coming into the Emergency room."
       "He was unresponsive even to deep painful stimuli."  ...
       "temperature of 95., heart rate of 120, {*filter*} pressure of 122/70 and
        respiratory rate of 24 per minute." ...
       "white platelet count 389."
       "His {*filter*} gas on admission was a pH of 7.45, pCO2 14, pO2 420."
       "his {*filter*} pressure dropped soon after arrival in the Emergency room
       to 85/systolic."
       "pressure remained low in the 80s systolic in spite of maximum dosage
        of Dopamine"
       "patient continued to deteriorate ... pronuounced dead" three hours
        after his admission to the Emergency room.
A half eaten apple was found in his car and was probably the last thing he
ate. Is there something that can be triggered by consuming an apple?

Are there more details needed to fill in the BLANK(?) for what might have
caused his death?

       [clipped excerpts from 'Death Summary']

Yes.  The death summary is a document delineating the circumstances
surrounding the hospital-based portion of a person's death.  Very often,
in cases where the cause of death is obscure and rapid (hours), the death
summary sheds little light.  What is needed is an autopsy report, as a
starting point.

In *theory*, such a death could come from a huge variety of causes,
ranging from an allergic (anaphylactic) reaction to the apple (or
something on it), through poisoning (?via the apple), to causes unrelated
to the apple (stroke of heart attack which happened to occur at that
moment).  Good Luck!  ...Larry.
==================================================================
|                                                                |
|   Morning Routine:  |-( <- { c[] + c[] + c[] + c[] } => :-))   |
|                                                                |
==================================================================