Abdominal pain for 4 weeks accompanied with emesia and diarrhea--To request etiological factor and treatment?

A 57-year-old male was admitted to our hospital on May 4th ,2007 for abdominal pain for four weeks accompanied with emesia and diarrhea. The clinical findings are listed in Table 1.
Past medical history and general state of health:
The patient鈥檚 past medical history was significant for spinal stenosis about two years ago, accompanied with the symmetry pain of limbs arthrosis for one year. He denied other systemic diseases and any surgical history, as well as family history of genetic disorder. Before the onset of the disease ,the patient had the history of exposure to a small amount of acetone(He is a aircraft mechanic). He denied the history of exposure to special food ,drug and toxicant.
Since the pathogenesis , the patient has no fever and night sweat, no skin petechia and skin rashes .There is a 2.5 kg weight loss recently.
Medical examination:
Left lower quadrant and superior belly had scattered tendernesses, no rebound tenderness. Other examinations were negative.
Table 1 Clinical manifestations of the patient:
Main clinical manifestations abdominal pain : Started left lower abdomen pain ,and then emerging superior belly pain, accompanied with nausea
frequent emesia : Vomiting after eating a little food, and Vomitus were a small amount of stomach contents
chronic diarrhea : watery stool, and there were no mucus ,pus and blood in the stool. More than 10 times a day ,and the quantity of toties quoties was 50-100ml.
Laboratory positive findings Blood routine---WBCC:7.8*109/L, Lymphocyte Percentage:10%, neutrophils Percentage:84.5%, Eosinophil count:0.6*109/L;
Albumin: 31-33g/L, prealbumin:142mg/L; blood calcium: 1.97-2.02mmol/L , blood phosphonium: 0.80-0.97mmol/L ,PTH:174ng/L, Calcitionin:3.4ng/L ;
blood sedimentation: 24mm/h, Ferritin: 924.9ng/mL;
Anti-SS-A:+, ANA:+++, Alexine C3:0.77g/L,CRP 36.6mg/L ; Serum transferrin: 1.97g/L;
Urine protein:+, Quantitation of Urine protein in 24h: Microamount albumen 196mg/L, Transferrin 11.1mg/L, Microglobulin 41.2 mg/L , IgG 31.3mg/L. Stool smear:a little Capsule protozoon锛?br> Endoscopy findings Coloscope showed that mucous membranes of colon and rectum had extensive dropsy, as well as rectal scattered anabrosis.
Gastroscope showed superficial gastritis , accompanied with anabrosis.
Image findings Computer tomography (CT) of epigastric zone showing edema of gastric wall and duodenal wall, right pleural effusion, seroperitoneum and bilateral hydronephrosis ;
Computer tomography (CT) of hypogastric zone showing thickening and edema of the part small intestine, ascending colon, sigmoid colon and rectum, furthermore , abnormal thickening of Bladder wall left; Computer tomography (CT) of chest showing right pleural effusion;
B ultrasonic of glandula thyreoidea showing a mixed tumor and a solid tumor on the right, furthermore ,a left thyroid nodules .
MRI of glandula thyreoidea showing multiple innocuousness nodules in right thyroid
ECT of epithelial body showing no obviously abnormal.

Pathological findings Rectal chronic inflammation

Other examinations (such as stool routine , stool culture ,tuberculin test, hepar and renal function, thyroid function, tumor markers, prothrombin time, HIV TPPA TRUST ,rheumatoid factor, anti-O, IgA E G M, C4 CH50 CIC, dsDNA anti-SS-B anti-SM, ACLA ,ANCA and B ultrasonic of the heart) were all negative.
To the treat and turnover:
After admission, we gave the patient the treatment of restrain acidum 锛圠osec锛? anti-inflammatory锛圕eftriaxone and metronidazole锛塧nd nutritional support. But the patient鈥檚 pathogenetic condition didn鈥檛 take a favorable turn. Since May 10th , we have given the patient hormone therapy---300mg hydrocortisone iv gtt qd. Currently , the patient still has abdominal pain and diarrhea.
To request:
1. to diagnose: about the etiological factor and etiopathogenisis
2.to treat: such as some better therapeutic regimens and some precious clinic experience

Interesting case, but perhaps this would be more appropriate for posting in the infectious disease section. Your description of a gastroenteritis picture and stool cultures showing a parasite (protozoan?) seems to indicate this. A few of your terms are foreign to me (rectum "dropsy" and "anabrosis"). Also your description of a diffuse inflammation and pleurisy is also unusual and a very systemic manifestation of this disease. You might consider tapping these effusions and/or laparoscopy?