Small Bowel Obstruction
Adhesions, herniation
Spasmodic pain in 3-5 min intervals
String of pearls, air fluid levels, step-laddering
NG tube, fluids, ABX
Never let the sun set or rise on a SBO
Obstructive Series
Need only Upright Chest and Upright Abdomen
A – Age over 50
B – Bowel sounds diminished
D – Distension (objective, not subjective)
O – Obstipation or constipation
X – previous surgery (a bit of a stretch – the “X” conjures up scars)
R – Ralfing (vomiting
)
Eur J Surg 1998 Oct; 164 (10): 778-84)
Also consider the elderly to evaluate for sigmoid volvulus
simple obstruction-bowel blocked, but vascular supply intact
strangulation-obstruction-vascular supply is compromised
closed loop-obstructed loop of bowel at both proximal and distal
partial vs. complete
the pain of strangulation is constant rather than colicky
drip and suck=conservative management
gastrograffin challenge
100 cc of gastrograffin is placed through the ng and then it is clamped for 2 hours
then get a simple abd film
Biondo S, Pares D, Mora L, Marti Rague J, Kreisler E, Jaurrieta E. Related Articles, Links Randomized clinical study of Gastrografin administration in patients with adhesive small bowel obstruction. Br J Surg. 2003 May;90(5):542-6.
Choi HK, Chu KW, Law WL. Related Articles, Links Therapeutic value of gastrografin in adhesive small bowel obstruction after unsuccessful conservative treatment: a prospective randomized trial. Ann Surg. 2002 Jul;236(1):1-6.
In the virgin abdomen
gastrograffin challenge and then CT scan
Intussusception
Small bowel volvulus in adults
Fluid filled small bowel twisted upon itself caused a closed loop and vascular compromise
Epidemiology:
· 5-10 times more common in third world than western world (Gurleyik)
· Responsible for 3%-6% of small bowel obstructions
· More common in pregnancy (volvulus responsible for ¼ SBO with SB volvulus first followed by cecal and sigmoid).
· 10 fold increase in Afghanistan during Ramadam
Etiology:
· Cause currently not completely understood
· High bulk diet eaten rapidly on an empty stomach
· May be secondary to abnormal mechanics (i.e. secondary to adhesions, Meckel’s diverticula, internal hernias, Ascariasis, or pregnancy).
Signs/Symptoms:
· Severe, central pain
· Signs of obstruction
Laboratory:
· Not helpful in making the diagnosis
Radiology: (Chou)
· Plain film radiographs: non-specific, may show only a gasless abdomen or signs of mild obstruction
· Barium swallow may show “corkscrew pattern”
· CT or MRI may show “”whirl” sign
· Angiography shows spiraling of the branches of the twisted SMA causing a “barber pole” appearance
Treatment:
· Immediate surgery with derotation and fixation or resection for ischemic bowel
Prognosis
· Mortality 10%-35%, much higher when bowel becomes ischemic
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Inguinal Hernia
Incarceration” meaning to imprison or confine.[
refers to a hernia that is not reducible and without signs of obstruction or strangulation.
Obstructing hernias present with
signs and symptoms of an intestinal obstruction: nausea, vomiting, abdominal distension, obstipation, and abdominal pain. On examination, a prominent hernia might be apparent but can be difficult to detect in the obese patient or if the hernia is femoral in nature. Treatment is urgent and whereas some surgeons might attempt initial reduction and subsequent early elective repair, most would agree on early surgical intervention. Any attempt at manual reduction of an obstructed hernia should be performed under adequate sedation and analgesia and without excessive force to prevent intestinal perforation. Useful adjuncts to this include retraction of the testis to “break the suction force” and gently massaging the hernia toward the internal ring.
Strangulation implies a compromised vascular supply with gangrenous bowel and is a surgical emergency requiring immediate surgical attention. Patients with strangulation usually present with a hernia that is not only irreducible, but also shows signs of inflammation with redness, pain, and extreme tenderness. They can also have signs of intestinal obstruction and dehydration, progressing to sepsis and toxicity.
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Mesenteric Ischemia
Most often in the SMA. Embolus or in 15-25% of cases thrombus (may have longer pain duration due to time to develop collateral circulation.)
A-Fib, CHF, dysrhythmias, MI predispose
Can also occur as a result of mesenteric vasospasm (Nonocclusive MI) in low flow states.
Severe colicky periumbilical abd pain c recurrent forceful BMs/Pain out of proportion to exam.
N/V. GI Bleed.
bowel empties as it gets more ischemic, so these patients WILL have diarrhea
Intestinal ischemia gives Ý phosphate, necrosis gives lactate
Superior Mesenteric Venous Thrombosis
accounts for ~5% of mesenteric Ischemia. Pain can progress over days to a week before presentation. Seen primarily in hypercoaguable states.
Intestinal Angina
chronic mesenteric Ischemia periumbilical pain 30 minutes after eating that lasts 1-2 hrs.
mesenteric venous thrombosis
ct shows hypodensity in trunk of SMV
associated with intraperitoneal fluid
and thickened segment of small bowel
mesenteric ischemia arterial embolism (50%) arterial thrombosis (25%) nonocclusive mesenteric ischemia (NOMI) 20% mesenteric venous thrombosis (MVT) <5% start with plain abd film look for bowel wall thickening, thumb-printing, pneumatosis intestinalis, and portal vein gas NOMI-angiographically placed catheter infusion of vasodilators such as papaverine MVT gets heparin and possibly lysis or thrombectomy assessment of bowel viability is better with fluoroscein than judgement in arterial embolism/thrombosis
Small Bowel Ischemia Leukocytosis: common, nonspecific Hemoconcentration, metabolic acidosis with base deficit, hyperamylasemia: nonspecific, present in >50% Lactate: ~100% sensitive, 42 87% specific Ruotolo RA, et al. Clin Geriatr Med. 1999 Aug;15(3):527-57.
Differential Diagnosis:
· AAA
· Cardiac ischemia
· Mesenteric ischemia
The treating physicians were worried about the 3 vascular abdominal emergencies in the elderly and took steps to rule them out. Additionally, 22-40% of elderly ED patients with abdominal pain require surgical treatment and 7% of those >80 years will die.
Given the unchanged EKG and stable vital signs a stat abdominal CT was ordered along with immediate surgical consult for possible mesenteric ischemia. Final radiologist reading of a triple contrast CT was: Intrahepatic biliary dilatation and small amount of perihepatic fluid consistent with acute hepatic process and large amount of colonic stool consistent with fecal impaction.
Diagnosis?
Can this patient be discharged with the diagnosis of constipation and/or “an acute hepatic process”?
Thankfully the initial reading of the CT by the radiology resident was: distended small bowel with a thickened wall, some free fluid, and mild biliary dilatation.
Although the CT scan was consistent with mesenteric ischemia, the patient’s pain improved intermittently after Fentanyl and the surgical service declined to operate immediately on the patient. The new shift of emergency physicians ordered a mesenteric angiogram, which was done approximately 2 hours after being ordered. Initial reading of the angiogram was consistent with mesenteric ischemia.
Acute Arterial Occlusive Mesenteric Ischemia
Pathophysiology:
· Thrombosis or emboli occlude arterial blood supply to intestines
· Emboli almost always involve the superior mesenteric artery
Epidemiology:
· Occurs almost exclusively in patients with atherosclerotic disease
Etiology:
· Emboli most often from clot in the left atrium or ventricle, occasionally from aortic thrombus
· Thrombus develops via atherogenic process
· Cardiac and/or vascular pathology common: CAD, valvular disease, atrial fibrillation, post MI mural thrombi, aortic instrumentation
Signs/Symptoms:
· Sudden onset of severe periumbilical pain
· May have nausea, vomiting, and diarrhea
· Hallmark: pain out of proportion to physical exam
· 75% of patient have heme negative stool
· If ischemia progresses untreated, the patient will develop tenderness, peritoneal signs, and shock
Laboratory:
· No test sensitive enough to rule out diagnosis reliably
· Lactate, WBC, and phosphate studies: only elevated consistently when bowel is already necrotic; Leo found phosphate only 26% sensitive.
· Labs may be entirely normal early on in course of disease
Radiology:
· Plain films
1) Usually normal or nonspecific
2) Late findings include intramural air (pneumatosis intestinalis), thickened bowel wall with “thumbprinting”, and portal venous gas
· CT Scan
1) Often normal or non-specific
2) Most common finding: bowel wall thickening (non-specific)
3) Specific findings include pneumatosis intestinalis, portal venous gas, abnormal bowel enhancement, and mesenteric vessel occlusion
4) Sensitivity 64%-82% (Taourel 1996) but can diagnose other important pathologies in the differential.
· Doppler ultrasound and MRI not well studied, may be helpful in the future
· Angiography
1) Gold standard
2) Only for stable patients without peritoneal signs; patients with an acute surgical abdomen should go directly to surgery
Treatment
· Aggressive diagnostic approach warranted as mortality is significantly increased by small delays in treatment.
· Most patients require fluid resuscitation secondary to third space fluid loss.
· Surgical resection of ischemic bowel and/or embolectomy of involved vessel have been the standard of care.
· Newer therapies involve intra-arterial infusions of papaverine or thrombolitics coupled with laparoscopy in patients without peritonitis. ( Regan 1996)
Hospital course:
The patient was taken to the operating room with a pre-op diagnosis of mesenteric ischemia. In the OR, surgeons found that in the middle portion of the jejunum, the small bowel was twisted to the point that it became strangulated. Final reading of the angiogram showed: Non-opacification of the distal jejunal branches, ileal branches and ileocolic branch of the superior mesenteric artery. No definite evidence of embolism is identified. Moderately dilated bowel in the region of hypovascularity. These findings are suggestive of a mid gut volvulus.
True diagnosis: intestinal ischemia secondary to small bowel volvulus
Teaching points:
1) Suspect mesenteric ischemia in all elderly with severe abdominal pain without significant tenderness.
2) Don’t be dissuaded from a proper diagnostic evaluation by radiographic diagnoses that don’t fit the severity of the patient and when faced with 2 interpretations always consider the most dangerous one first.
3) The only methods to “rule out” mesenteric ischemia are angiography and surgery, but CT often will provide alternative important diagnoses.
Hepatic Portal Venous Gas On CT Scan in the ED Hepatic portal venous gas (HPVG) is a radiologic finding that occurs when gas from the intestinal lumen passes through the intestinal wall and travels via the mesenteric veins to the portal vein and into the liver. Most cases of HPVG are related to mesenteric ischemia and this finding has traditionally been associated with a high mortality. However, CT scan has greatly increased the sensitivity for the detection of HPVG. As a result, the clinical outcome of patients with mesenteric ischemia has improved and there has been an increasing rate of detection of HPVG with certain nonischemic conditions. Conditions that have been reported to result in HPVG include inflammatory bowel disease (both CrohnÂs disease and ulcerative colitis), diverticulitis, intestinal obstruction, blunt abdominal trauma, gastric ulcer, intraabdominal abscess, cholangitis, and complications of iatrogenic procedures (e.g. ERCP and colonoscopy) (1-4). Emergency Physicians, then, need to be aware that HPVG is not a specific disease entity, but merely a diagnostic clue in patients with acute abdominal pathology and when portal venous gas is detected in the ED, it is important to differentiate life-threatening mesenteric ischemia from other more benign nonischemic causes (1). It is known that the presence of HPVG carries a much less severe prognosis when found on CT as compared to the finding of gas on plain radiographs (1,4). Therefore, the finding of HPVG on CT should be carefully evaluated in the context of clinical findings. In certain cases, the prognosis is favorable and surgery is not required. However, when CT demonstrates portomesenteric vein gas and clinical findings suggest the presence of mesenteric ischemia, surgery is mandatory. Of note, it has been reported that the presence of gas simultaneously in the portal venous system and intestinal wall seems to be specific to intestinal ischemia (5).
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