Learn Russian: У вас сильное воспаление, следовательно, это инфекция. - You have severe inflammation; consequently, it is an infection.

Следовательно implies a logical deduction or a conclusion drawn directly from evidence (the inflammation proves there is an infection). It sounds more analytical and formal than поэтому, which simply links a cause to a resulting action, or значит, which is a more conversational way to say 'so' or 'that means'.

Why is следовательно surrounded by commas here?

In Russian, следовательно acts as an introductory word (вводное слово) when it means 'consequently' or 'therefore.' Just like 'consequently' in English, these structural markers are not considered official members of the sentence and must be separated by commas.

Why use сильное (strong) instead of a word like серьёзное (serious) for 'severe'?

In Russian, сильный is the standard adjective used to describe intense physical symptoms, such as сильная боль (severe pain) or сильное воспаление (severe inflammation). While a doctor might use серьёзное to describe a broader medical condition, сильное is the natural collocation for the intensity of a specific symptom.

Could we drop это and just say следовательно, инфекция?