This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genital Tract Infections (Too hot to handle!), Subject name: Gynaecology & Obstetrics
Common mode of transmission in pyogenic TB salpingitis: 
Select and explain. 
A. Hematogenous, B. Ascending infection, C. Direct invasion, D. Sexually transmitted
A: Hematogenous
Answer: A: Hematogenous 
Explanation: Genital tuberculosis occurs almost always secondary to a primary focus elsewhere, The commonest site being the lungs (50%), but rarely from other sites such as lymph nodes (40%), the kidneys, joints, gastrointestinal tract or as pa of a generalized miliary infection. The mode of spread is generally haematogenous or lymphatics, and rarely from direct contiguity with an intra-abdominal organ or affected peritoneum.