I have suffered from sinusitis for some 15 years and have had two
operations, the first was basically a 'cleaning and wash-out' exercise and
the second was to enlarge my left nasal passage which had suffered
mechanical damage when I was a teenager (playing rugby!).  On both occasions
the surgeon said my sinuses were clear and clean.

The second operation made a significant improvement but I still suffer from
attacks of what I call 'sinusitis' although the symptoms are atypical.  I
get extremely tired and am unable to think clearly.  Pain often does not
develop for some days and in the case of the most recent attack 3 weeks
after the initial symptoms - I just felt a slight discomfort across my eyes,
more a feeling of tiredness than real pain.  I have a post-nasal drip most
of the time so I don't specifically associate this with a 'sinus' attack,
although it is always present when I do have an attack.  The tiredness and
inability to think clearly are the greatest problems as this has a very
serious effect on my work.

The most recent attack was treated with penicillin (Amoxicillin, if I
remember correctly).  This made a significant improvement at about day 6 of
the 7 day course of treatment but over the next week or so I became
lethargic again.  This time the problem responded after about 3 days to
Sudafed (pseudoephedrine hydrochloride) although I still don't feel entirely
recovered.  When the attack responds to treatment the change from feeling
debilitated to 'wide-awake' is instantaneous, almost as though someone had
switched on an electrical light.

My doctor seems perplexed by my condition, particularly as I have no pain.
Any suggestions as to either cause, diagnosis or treatment would be very
welcome.

Thanks, Bill