Hi all,
There are many causes for what we commonly call "bloat". This is a syndrome where generalized subcutaneous edema develops (fluid retention) because the skin is no longer able to maintain water homeostasis. The causes are as follows:
1. Bacterial (or other infectious agents);
2. Hepatic failure;
3. Renal failure;
4. Malnutrition (usually lack of proteins or calcium);
5. Osnotic imbalances (ex: exposure to distilled water);
6. Ovarian tumors or cysts.
Ideally, one should try to look for the exact cause but often this is impossible. Anyway, husbandry should throughly revised (including water parameters, feeding) and some water chemistry analysis. To diagnose some of these diseases it's necessary some laboratory workout done by a veterinarian (bloodwork, Xray, fecal analysis,...). Aspiration of this fluid and it's microscopic analysis would be of great importance.
Supportive care includes bathing in amphibian ringer's solution and trating the underlying etiology (antibiotics if infection, force-feeding if malnutrition, suplementation with calcium or vitamins). As for renal and hepatic failure, treatment is usually unrewarding...
As for this case with localized edema on the throat the causes could also include some disfunction of the lymph heart that drains fluids from this area (ex: trauma, obstruction with crystals, parasites, abcesses, tumors or scar tissue). Providing that the cause of this localized edema isn't a dangerous one (like obstruction from oxalate crystals) most animals survive quite well and in some cases it may even regress spontaneously.
Hope I didn't confuse you
Let me know if you need anything else
Filipe