Diagnosis of the Starved Space Traveler

Question

One day (in a universe very unlike our own) a wealthy adventurer set off in an obscure direction from his home solar system into the depths of space. But he made a dire mistake: Before getting into his cryosleep casket, he forgot to change the time setting off of "indefinite." And so any astronomer of the time would've expected his suspended corpse to have drifted aimlessly through space forever.

But recently, after an uncertain amount of time (centuries? millennia? even longer?) his ship was detected and recovered by a friendly cruiser from near his home system. Even more mysterious than his unaided return, however, was his subsequent condition and behavior: Although his body was suspended and reanimated perfectly, he has been in a confused state since his awakening. He is reticent in explaining his symptoms—perhaps for fear of being labeled insane—but his observed symptoms are as follows:

1. Clumsiness operating contraptions common to his era.
2. Slowness understanding or producing written English, but has no problems verbally.
3. Strange reactions to tastes and odors that should be familiar to him, but no strange reactions aurally.
4. Some of his medications are having strange effects on him, or no longer produce therapeutic responses at all; other medications are behaving exactly as they always have.
5. He scores just as well on cognitive exams as he did before (pending 2); you are certain he is not experiencing dementia.
6. Most seriously, despite resuming his ordinary eating habits upon awakening, he suffers from extreme indigestion and weight loss, and is on the verge of death from malnutrition after only six weeks.

You are a doctor charged with saving his life. You take a CT scan of his abdominal cavity as a preliminary diagnostic procedure, and what you see is surprising but not unheard of (it affects about 0.01% of the population, almost entirely asymptomatically). However, in a stroke of intuition it leads you straight to a very surprising diagnosis. What did you see, and what is your diagnosis?

Answer 1

The astronaut has gone through

the fourth (spacial) dimension and was turned over, therefore coming out in 3d space in mirror image.
Edit: In the comments Feryll pointed out non-orientable wormholes or "Alice handles" through which he may have travelled. Note that such a wormhole would probably turn matter into anti-matter, which gives rather more serious problems. I think that in theory this would happen with any solution that mirrored subatomic particles, including the 4-dimensional rotation.

The doctor saw he had

situs inversus, the major organs arranged in mirror image.

That condition normally

will not affect any chemical processes, but for this astronaut all his molecules are flipped too, including all amino acids, so he is unable to absorb most nutrients and vitamins. This also affects the chemical processes that detect smells. Reading and writing would also be difficult in mirror image.