Am i write in thinking that although hypostatic pneumonia is not itself an infection it can be caused by an infection? but can it have other causes?

Bedridden immobility: Hypostatic pneumonia comes from shallow breathing while lying in a single position for a long time. Therefore bronchial secretions usually cleared by deep breathing & coughing instead settle by gravity in lower portions of the lung & become seats of infection. Usually in bedridden elderly. Also big reason why activity is encouraged right after major surgery. Hope that helps.