English term (edited): imp (disease)

I think this is most likely in the context. In lists of medical abbreviations, "IMP" is found with several meanings:

"IMP, immuno magnetic particles.
Imp, impression.
IMP, improved.
IMP, inosine 5'-monophosphate."
http://abbreviations.virtualsplat.com/category/medical-abbre...

"Improved" would be plausible if the document were dealing here with the recent clinical history of the patient. But here it occurs in the list of observations in the physical examination, and most probably corresponds to a tentative diagnosis corresponding to the symptoms just reported.

"Generally, however, the medical record begins with the patient's chief complaint (CC), medical history (Hx), or history of the present illness (HPI) plus past history (Past Hx), and review of systems (ROS). There may be separate entries for family history (Fam Hx) and/or social history (Soc Hx). Next is the physical examination (PE), usually listed by organ systems of the body.
Either directly following the history and physical examination, or at some point later, the physician will first state an impression (Imp), tentative diagnosis (Dx), or differential diagnosis (DDx). For some patients, the presence of a possible malignancy will be first detected on the initial physical examination in the hospital."
http://training.seer.cancer.gov/abstracting/procedures/

--------------------------------------------------
Note added at 54 mins (2014-03-30 11:55:28 GMT)
--------------------------------------------------

The following document contains several clinical reports with "IMP" where it does seem to mean "impression" (in the sense of preliminary diagnosis):

"IMP: several issues which need to be followed up."
"IMP: infective exacerbation COPD."
"IMP: Herpes zoster."
And so on
http://www.icgp.ie/speck/properties/asset/asset.cfm?type=Doc...