hello and thank you for asking HCM, I understand your concern, especially while it is affecting your son. Regarding symptoms you mentioned, it seems like your son is having mononucleosis. These diagnosis can be confirmed by doing additional examination (The 3 classic criteria for laboratory confirmation of acute infectious mononucleosis include lymphocytosis, the presence of at least 10% atypical lymphocytes on peripheral smear, and a positive serologic test result for Epstein-Barr virus (EBV)). LDH and AST are liver enzymes which normally increase in this disease. But there is no reason to fear, while infectious mononucleosis is a self-limited illness that does not usually require specific therapy in patients with mild or moderate illness. Which means that the levels of LDH nad AST will return to normal. However, if the tonsils are markedly enlarged (kissing tonsils) or if the patient has prolonged illness, most experts recommend a short course of steroids (1-2 mg/kg of prednisone daily for 3-7 d). My suggestion is to visit your GP and check with him this possible diagnosis and see if your son needs special therapy or not. Until then avoide any kind of effort and closer contact with people. I hope this answer was helpful to you.