A 15-year-old male reports dull pain in both knees. Sometimes one or both knees click, and the patient describes a

catching sensation under the patella. In determining the causes of the knee pain, what additional history do you need?  What categories can you use to differentiate knee pain? What are your specific differential diagnoses for knee pain? What physical examination will you perform? What anatomic structures are you assessing as part of the physical examination? What special maneuvers will you perform?

What is the differential diagnosis in the below case study?

Jimmy is a 3-year-old “picky” eater

according to his mother. He refuses to eat anything but waffles for breakfast and macaroni and cheese or chicken nuggets for lunch and dinner. He will eat apples and bananas but refuses all vegetables except corn. After a normal physical examination, you obtained blood testing that revealed the hemoglobin is 11.4 mg/dl and his hematocrit is 30% (both obtained by venipuncture). The CBC revealed microcytic hypochromic RBCs.