Pathophysiology: What specifically is causing this patient\'s current pain crisis? Patient Case Question 2. What specifically is causing this patient\'s current pain crisis? Solution The patient has consumed less water and performed rigorous exercises causing dehydration and hemoconcentration. Due to this, the sickle cell rbc are concentrated at the capillaries and block the fine capillaries causing severe pain. Sickle cells cannot pass through the capillaries like normal rbc..