▁or ▁ar ter itis ▁are ▁also ▁defined ▁as ▁secondary ▁head aches . ▁This ▁type ▁of ▁head aches ▁may ▁also ▁be ▁caused ▁by ▁c ere br al ▁ven ous ▁th rom b osis ▁or ▁different ▁int rac ran ial ▁v asc ular ▁dis orders . ▁Other ▁secondary ▁head aches ▁are ▁those ▁due ▁to ▁int rac ran ial ▁dis orders ▁that ▁are ▁not ▁v asc ular ▁such ▁as ▁low ▁or ▁high ▁pressure ▁of ▁the ▁c ere bro sp inal ▁fluid ▁pressure , ▁non - in fect ious ▁infl am mat ory ▁disease , ▁int rac ran ial ▁ne op las m , ▁ep ile ptic ▁se iz ure ▁or ▁other ▁types ▁of ▁dis orders ▁or ▁dise ases ▁that ▁are ▁int rac ran ial ▁but ▁that ▁are ▁not ▁associated ▁with ▁the ▁vas cul ature ▁of ▁the ▁central ▁nerv ous ▁system . ▁I CH D - 2 ▁class ifies ▁head aches ▁that ▁are ▁caused ▁by ▁the ▁ing estion ▁of ▁a ▁certain ▁subst ance ▁or ▁by ▁its ▁withdraw al ▁as ▁secondary ▁head aches ▁as ▁well . ▁This ▁type ▁of ▁head ache ▁may ▁result ▁from ▁the ▁over use ▁of ▁some ▁medic ations ▁or ▁by ▁expos ure ▁to ▁some ▁subst ances . ▁H IV / A ID S , ▁int rac ran ial ▁in fe ctions ▁and ▁system ic ▁in fe ctions ▁may ▁also ▁cause ▁secondary ▁head aches . ▁The ▁I CH D - 2 ▁system ▁of ▁classification ▁includes ▁the ▁head aches ▁associated ▁with ▁home ost asis ▁dis orders ▁in ▁the ▁category ▁of ▁secondary ▁head aches . ▁This ▁means ▁that