A 68-year-old male presents to the emergency department after experiencing a sudden worsening of symptoms he initially attributed to chronic constipation. For the past week, he has had intermittent, crampy abdominal pain, which has become constant and severe over the last 24 hours, accompanied by persistent, non-bloody bilious vomiting. He reports absolute obstipation (no bowel movement or flatus) for 48 hours. His past medical history includes an appendectomy 15 years ago and well-controlled hypertension. On examination, his blood pressure is 120/75 mmHg, pulse is 92/min, respiratory rate is 18/min, and temperature is 37.5 C (99.5 F). Abdominal examination reveals significant distention, diffuse mild tenderness, particularly in the lower quadrants, and high-pitched, tinkling bowel sounds that are intermittent. There is no guarding or rebound tenderness. Digital rectal exam reveals an empty rectal vault. What is the most appropriate initial diagnostic approach and subsequent immediate management strategy for this patient?

A 68-year-old male presents to the Emergency Department complaining of progressively worsening abdominal pain, nausea, and persistent vomiting for the past 24 hours. He reports no recent bowel movements or flatus. His medical history is significant for an open appendectomy performed 15 years ago. On physical examination, he appears distressed with a distended, diffusely tender abdomen, though without rebound tenderness or guarding. Bowel sounds are initially hyperactive, then become sparse on re-examination. An abdominal X-ray is performed, revealing multiple dilated small bowel loops with air-fluid levels and a paucity of colonic gas. His vital signs are T 37.8°C, HR 105 bpm, BP 100/60 mmHg, RR 18/min, SpO2 98% on room air. Given these findings, what is the most likely diagnosis, and what is the most appropriate initial management strategy to prevent complications?

A 68-year-old man presents to the emergency department with a 2-day history of escalating cramping abdominal pain, abdominal distention, and intermittent episodes of non-bilious vomiting. He reports no prior abdominal surgeries but acknowledges a remote history of symptomatic gallstones that were managed conservatively. His current vital signs include a temperature of 37.8 C (100.0 F), blood pressure of 115/70 mm Hg, pulse of 105/min, and respirations of 20/min. Physical examination reveals a distended abdomen with diffuse mild tenderness, most prominent in the periumbilical region, and hyperactive, high-pitched bowel sounds. There is no rebound tenderness or guarding. Imaging from a plain abdominal X-ray shows multiple dilated loops of small bowel with air-fluid levels and air visible within the biliary tree. No gas is observed in the colon, and there is no evidence of free intraperitoneal air. Labs reveal an elevated white blood cell count and mild electrolyte abnormalities. Given these findings, what is the most likely diagnosis, and what is the most appropriate immediate surgical intervention?

A 62-year-old woman, 7 years post-exploratory laparotomy for a ruptured ectopic pregnancy, presents to the emergency department with 4 days of worsening colicky abdominal pain, intractable bilious vomiting, and obstipation. She initially experienced intermittent mild discomfort but now reports severe, constant pain localized to the right lower quadrant. On initial assessment, her blood pressure is 100/60 mmHg, heart rate 110 bpm, respiratory rate 20 bpm, and temperature 38.8°C (101.8°F). Physical examination reveals a distended and markedly tender abdomen with localized guarding and rebound tenderness in the right lower quadrant. Initially, high-pitched, hyperactive bowel sounds were noted, but on repeat assessment, her abdomen is silent. Abdominal radiographs demonstrate multiple dilated small bowel loops with air-fluid levels and a paucity of colonic gas. Given her clinical presentation, laboratory findings, and radiological evidence, what is the most likely diagnosis, and what is the immediate, definitive management required to prevent life-threatening complications?

A 68-year-old male with a history of an open appendectomy 30 years prior and a remote inguinal hernia repair presents to the general surgical ward from the emergency department, having been admitted for escalating symptoms over the past 36 hours. He reports persistent, waxing and waning periumbilical abdominal pain, initially mild but now severe, associated with copious bilious vomiting, abdominal distension, and obstipation. He denies any recent changes in diet or medication. Upon examination, he appears acutely distressed. His abdomen is markedly distended, diffusely tender to palpation, and exhibits subtle guarding in the lower quadrants. High-pitched, tinkling bowel sounds are noted. His vital signs include a temperature of 38.9° C (102.0° F), blood pressure of 95/55 mm Hg, pulse of 135/min, and respirations of 28/min. A plain abdominal X-ray performed in the ED showed multiple dilated small bowel loops with air-fluid levels and a paucity of gas in the colon. He has already received intravenous fluid resuscitation and a nasogastric tube is in place draining bilious fluid. Given the evolving clinical picture, what is the most appropriate definitive diagnosis and the immediate therapeutic intervention required to prevent further complications?

A 60-year-old man presents to the emergency department with a 12-hour history of worsening colicky abdominal pain, progressively severe nausea, and multiple episodes of bilious to feculent vomiting. He underwent a laparoscopic colectomy for diverticulitis 3 months ago. Initially, he was passing some flatus, but he reports no bowel movements or gas passage for the past 6 hours. His vital signs are: blood pressure 100/70 mmHg, pulse 120/min, temperature 37.8 C, respiratory rate 20 /min. On physical examination, he is visibly dehydrated and appears to be in moderate distress. His abdomen is markedly distended with diffuse tenderness, hyperactive, high-pitched bowel sounds, and a well-healed midline surgical scar. There is no definite rebound tenderness, but guarding is present in the lower quadrants. Current lab results show: White Blood Cell Count: 13.5 x 10^9/L (Normal: 4.0-10.0 x 10^9/L), Potassium: 2.9 mmol/L (Normal: 3.5-5.0 mmol/L), Chloride: 88 mmol/L (Normal: 98-107 mmol/L), Bicarbonate: 32 mmol/L (Normal: 22-29 mmol/L), Blood Urea Nitrogen (BUN): 35 mg/dL (Normal: 7-20 mg/dL), Creatinine: 1.5 mg/dL (Normal: 0.6-1.2 mg/dL). Flat and upright abdominal x-rays reveal multiple dilated small bowel loops with prominent air-fluid levels and a paucity of gas in the colon. Considering his clinical presentation and imaging findings, what is the most likely diagnosis and the immediate next step in his management?

A 68-year-old male presents to the emergency department with several days of escalating abdominal pain, distension, and recurrent episodes of copious bilious emesis. His past medical history is significant for an appendectomy performed 15 years prior. On examination, he appears lethargic with dry mucous membranes and demonstrates significant abdominal tenderness and tympany with hyperactive bowel sounds. Imaging confirms a diagnosis of small bowel obstruction. Laboratory results reveal: Sodium: 132 mEq/L (Normal 135-145 mEq/L) Potassium: 2.8 mEq/L (Normal 3.5-5.0 mEq/L) Chloride: 85 mEq/L (Normal 96-106 mEq/L) Bicarbonate: 34 mEq/L (Normal 22-29 mEq/L) Blood Urea Nitrogen (BUN): 30 mg/dL (Normal 8-20 mg/dL) Creatinine: 1.3 mg/dL (Normal 0.6-1.2 mg/dL) Hemoglobin: 16 g/dL (Normal 13.5-17.5 g/dL) Hematocrit: 48% (Normal 39-50%) Given his clinical presentation and laboratory findings, what is the most likely metabolic derangement, and what is the immediate priority in his management to address this complication and prevent further cardiovascular manifestations?

A 70-year-old man presents to the surgical ward from the outpatient clinic, complaining of worsening diffuse abdominal pain, nausea, and bilious vomiting over the past 24 hours. He reports no bowel movement or passage of flatus for 4 days. His medical history is significant for an open appendectomy performed 35 years prior. On physical examination, his abdomen is distended and tympanitic to percussion, with hyperactive bowel sounds heard on auscultation. There is no rebound tenderness or guarding. His temperature is 38.2 C (100.8 F), heart rate is 105 bpm, and blood pressure is 100/60 mmHg. An abdominal X-ray series performed in the clinic showed multiple dilated loops of small bowel with numerous air-fluid levels arranged in a 'stepladder' pattern. Considering his clinical presentation and imaging findings, what is the most likely diagnosis, and what would be the immediate next step in his management?