Symbol Guide

(') at end of words = abbreviates guessable words and its tenses, doesn't give 'possessive function to words ending with 's'' so, watch the context of the sentence too.
Example: Diagnos' is not Diagnosis' or Diagnoses', but it's just Diagnosis or Diagnoses. 

('s) = may or may not abbreviates word, but certainly gives the function of normal ('s) in English irrespective of the last letter of the words. Example:
Px's = Patient's or Patient is or Patient has.
Dengue Fever's = Properties of Dengue Fever or Dengue Fever is or Dengue Fever has.

(Ø) = non- or not or negative tense.
Example:
Øspecific = nonspecific.
Ø 2phasic = not biphasic.

(~) = may or may be.

(w/) =  with.

(w/o) = without

((+)) = 'positive' or 'with' or 'develop', in other context it means 'required to be done'.
Example:
Head CT Scan ~ (+) to exclude few other differ' diagn' = Head CT Scan may be 'required to be done' to exclude few other differential diagnoses.

(+++) = Severe or prominent feature.

((+++)) = Very often.

And other symbols, eg: (♥) = '-cardia' or 'heart'.
Example: tachy♥ = tachycardia.