Las enfermedades
¿Necesita usar un articulo cuando hablando de una enfermedad?
Por ejemplo,
Perdidas del peso y dolor muscular son síntomas de la osteoporosis.
El paciente tiene la osteoporosis.
¿Es correcta?
2 Answers
Your statements are OK, but need a little touching up.
Las pérdidas del peso y el dolor muscular son síntomas de la osteoporosis.
El paciente tiene la osteoporosis.
Most of the time when discussing these items, when the symptoms are the subject of the sentence the articles are always used. There are some hispanohablantes who don't use the article when the symptom or the disease is the direct object as in, "El paciente tiene la osteoporosis." Some would omit the "la." , but I don't.

Just a thing:
cuando hablando does not make sense because it's a literal translation from when speaking. This in English makes sense because it's the shortened form of when you are speaking. Hence, you need to use the full form cuando estás/estés hablando. (Indicative or subjunctive depending on the case.)