If you're creating your own lookup table sort of thing, you could use arrays to shorten the syntax a bit, e.g.:
$symbol = array(
'USD' => '$',
'EUR' => '€',
'GBP' => '£',
'JPY' => '¥',
/* etc */
);
echo "Your total amount is: " . $symbol[$currency_abbreviation] . $amount;
EDIT: In case you haven't come across it, this was my source.