Is the word sintomas the same in Brazilian and European Portuguese?

Yes.

The word "sintomas" is identical in spelling, meaning, and grammatical function in both Brazilian and Continental Portuguese. The only differences are phonetic:

• Vowel Reduction: In Brazilian Portuguese, the unstressed "o" is typically pronounced as a clear [u] sound (sin-TO-mus). In Continental Portuguese, unstressed vowels are often more heavily reduced or "swallowed."
• Sibilance: In many regions of Portugal, the "s" at the end of the word is pronounced as a "sh" sound ([ʃ]), whereas in most of Brazil, it is pronounced as a dental "s" sound ([s]).

Brazilian Portuguese Examples

1. Ela está com sintomas de gripe. (She has flu symptoms.)
2. Quais são os seus principais sintomas? (What are your main symptoms?)
3. Os sintomas de alergia apareceram muito rápido. (The allergy symptoms appeared very quickly.)
4. Não ignore os sintomas de estresse. (Do not ignore the symptoms of stress.)
5. Ele apresentou sintomas leves durante a noite. (He presented mild symptoms during the night.)

Continental Portuguese Examples

1. Ela apresenta sintomas de gripe. (She presents flu symptoms.)
2. Quais são os sintomas que sente? (What are the symptoms you feel?)
3. Os sintomas alérgicos manifestaram-se depressa. (Allergic symptoms manifested quickly.)
4. É importante vigiar os sintomas da doença. (It is important to monitor the symptoms of the disease.)
5. Os sintomas são bastante claros. (The symptoms are quite clear.)