I would second the notion that you should test the patient for GC, chlamydia, and probably HIV as well as syphilis. If the patient is a woman you must, must, must do a pregnancy test since congenital syphilis is devastating. you also should try to get the names of the patient's sexual partners and report them along with the case to the local health board (syphilis is a reportable illness) so that the partners can be notified. You could work the patient up for false-positive causes of +VDRL if there is no history of a genital lesion.
In terms of the indicated antibiotic treatment, here is the direct quote from Harrison's 15th ed: "Penicillin G is the drug of choice for all stages of syphilis...Penicillin G benzathine is the most widely used agent for the treatment of early stage syphilis...A single dose of 2.4 million units cures more than 95% of cases of primary syphilis." Finally, you should find out if the patient is selling their body for crack or other drugs (this quote again from Harrison's): "infectious syphilis has been correlated significantly with the exchange of sex for 'crack' cocaine" and then try to get them to go for drug treatment if they are engaging in this.
I hope this helps. to be honest I'm not sure what your attending was really getting at but as far as a shot in the dark as to his "read my mind questions" at least this one is from an accurate source.
