If Britain long felt like a sore festering at the heart of European unity, its planned departure has made one thing clear - it's far from the only malaise for the vision of a common European Union future.
After the June referendum vote in Britain to quit the EU, there are other issues the European bloc is grappling with as 28-minus-1 leaders meet for a summit at the centuries-old Bratislava Castle on Friday.
THE REFUGEE EMERGENCY
EU nations simply cannot agree how to manage this problems. Countries in the east - Hungary, Slovakia, the Czech Republic and others - have openly opposed proposed solutions coming out of Brussels and even defied the wishes of their neighbours.
ECONOMIC WOES
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Greece's place in the euro single currency has been called into question, and created a major rift between pro-austerity countries led by Germany and countries with more social-minded governments. Spain and Portugal face the threat of fines for failing to bring their budgets into line while France has avoided penalties, creating more strains.
THE EXTREMIST THREAT
Extremist attacks in Paris, Brussels and Germany combined with the lack of intelligence-sharing between member countries have undermined confidence that the EU can provide a solution and provided fodder for the far-right.
