A peptic ulcer is damage to the lining of the stomach (the cells). This damage causes bleeding and so your body loses blood. This is often slow and results in anaemia. (It can sometimes occur much quickly in which case it can cause black, tarry stools or vomiting of blood).
Loss of function in the bone marrow can lead to decreased production of red blood cells, white blood cells, and platelets. This can result in conditions such as anemia, increased susceptibility to infections, and impaired blood clotting. Treatment may involve blood transfusions or bone marrow transplant.
If this is a regular doctors visit, I'm not sure what you are afraid of. Your doctor cannot charge you with a crime. Generally if a doctor finds drug in your system they will suggest treatment or something of that nature. If you are on probation or the such you need not worry. Doctors are expressly prohibited from giving out any medical information on you due to HIPPA privacy rules enacted in 2003. The only time that they can release this kind of information would be in a situation that they are required by law, such as in the case of child abuse.
Many things can perturb the normal function of a neuron: - fluid electrolyte homeostasis (sodium, calcium, potassium, chloride - all have to be tightly regulated inside and outside the cell) - energy metabolism (diabetes) - temperature: cold lowers activity, heat destroys protein (meningitis kills via mechanism) - runaway signalling from other neurons (epilepsy) - drugs (illicit & prescribed) - toxins (animal/plant venoms) - pollutants/industrial chemicals