Patient presents with acute onset of severe epigastric pain, consistent with possible gastric perforation.  Symptoms include sudden, sharp abdominal pain radiating to the shoulder, accompanied by nausea, vomiting, and signs of shock.  Physical examination reveals abdominal rigidity, guarding, and rebound tenderness, suggestive of peritonitis.  Differential diagnosis includes peptic ulcer disease, perforated ulcer, acute abdomen, and other causes of gastrointestinal perforation.  Medical history significant for prior diagnosis of peptic ulcer disease and long-term NSAID use.  Initial laboratory tests ordered include complete blood count (CBC) with differential, comprehensive metabolic panel (CMP), and serum amylase and lipase.  Imaging studies, including an upright abdominal X-ray and abdominal CT scan with contrast, are requested to evaluate for free air under the diaphragm, a key indicator of gastric perforation.  Patient's clinical presentation and imaging findings support the diagnosis of gastric perforation.  Surgical consultation obtained for emergent surgical intervention, potentially laparoscopic or open repair of the perforation.  Treatment plan includes fluid resuscitation, broad-spectrum antibiotics for peritonitis, and pain management.  Patient's condition is critical, requiring close monitoring for complications such as sepsis, shock, and multi-organ dysfunction.  Prognosis depends on the timely diagnosis and surgical intervention.  ICD-10 code K25.1 (Gastric ulcer with perforation) is assigned.