There is no described professional intoxication from the use of this element. Data on its toxicity to man comes from its use as the treatment of choice in manic-depressive states, and from suicidal attempts.
Moderate side-effects
Diarrhea, nausea,
Feeling of thirst,
Vision troubles,
Tremors of the hands.
More severe side-effects
Memory disorders, tremors, muscular fasciculations,
Hyperactive tendon reflexes, dysarthria, giddiness.
Severe intoxication leads to convulsions and coma, which can be hyperosmolar.
Prolonged treatment
Interstitial nephritis, incomplete distal tubular acidosis,
Hyperparathyroidism (hypercalcemia),
Disturbances of the glucose metabolism, obesity,
Goiter, hypothyroidism,
Neutrophilia,
Various cutaneous lesions (psoriasis, acne, folliculitis, alopecia, etc.)
Toxic manifestations may occur when the serum concentration exceeds 10.4mg/L. A concentration higher than 25mg/L justifies treatment by dialysis.(1)
The toxic and therapeutic blood levels are very close, so any activity leading to loosing much body water may switch a patient taking lithium carbonate form the therapeutic to the toxic zone, as in sweating excessively in melting departments of steel mills.
Also, many anti-inflammatory drugs raise lithium blood levels of patients and may cause intoxication, one major offender being ibuprofen ( Motrin, Advil). It is important to remember this name because it may be sold without a prescription.
Other possible offenders are ketorolac (Toradol), diclofenac (Voltaren), indomethacin (Indocid), naproxen (Naprosyn), fenoprofen (Nalfon), celexobib (Celebrex), rofecoxib (Vioxx). (2)
There is no such thing as a single case of lithium intoxication described in the pertaining literature from the use of it in glaze making or from the use of ceramic wares covered by lithium-containing glazes.
The only lithium compound that is reported as a severe hazard is lithium hydride (LiH), which is used as a condensing agent in chemical synthesis with acid esters and ketones, as a dessicant (a reducing agent), and as a hydrogen source.
The hydride is a severe irritant to skin and mucous membranes because it becomes lithium hydroxide when in contact with the moisture of these structures.(3)
So, if you do not use the hydride, have a nice day.
References
Toxicologie Industrielle et Intoxications Professionnelles, Lauwerys R. last edition.
Sylvie Dumaine, pharmacist, Sorel-Tracy, Quebec, Canada (2002)
Occupational Medicine, Zenz Carl, last edition.