Updated: 6/10/2019

Paralytic / Adynamic Ileus

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  • A 47-year-old woman on the surgery floor complains of abdominal pain and bloating. She was admitted for appendicitis and underwent a laparoscopic appendectomy 2 days ago. She reports feeling fine since the surgery and denies any fever, swelling, hematuria, hematochezia, or nausea. Her last bowel movement was 3 days ago and she denies any flatulence. A physical examination is unremarkable except for a lack of bowel sounds.  
  • Clinical definition
    • medical condition characterized by the disruption of the normal coordinated propulsive motor activity (peristalsis) of the gastrointestinal tract without any structural/mechanical obstruction  
  • Epidemiology
    • demographics
      • gastrointestinal/abdominal surgery is the most common cause
    • risk factors
      • gastrointestinal surgery
      • electrolyte imbalance (e.g., hypokalemia or hypercalcemia) 
      • diabetes
      • medications (e.g., opioids or antimuscarinics)
      • spinal cord injury
      • severe illness
      • hypothyroidism
      • acute intermittent porphyria
  • Pathogenesis
    • the degree of intestinal paralysis does not need to be complete but enough to functionally prohibit the passage of food leading to intestinal blockage
    • normal gastrointestinal motility is controlled and facilitated by a complex network of various neural networks and neurohumoral peptides
      • enteric nervous system, which is the intrinsic neural network of the gastrointestinal system
      • extrinsic network consists of the visceral sensory afferents of the vagus, splanchnic, and pelvic nerves as well as the visceral motor efferent of the autonomic nervous system
    • gastrointestinal dysmotility can result from various mechanisms
      • inflammation (e.g., surgery or severe illness)
      • neural reflexes
      • neurohumoral peptides (e.g., certain medications)
  • Symptoms 
    • abdominal pain  
      • rarely presents as the colicky pain present in mechanical bowel obstruction
    • nausea
    • vomiting
    • vague discomfort
  • Physical exam
    • abdominal distension
    • lack of bowel sounds on auscultation
      • in contrast to the high-pitched tinkling sounds in mechanical bowel obstruction
    • no abdominal tenderness
  • Diagnostic testing
    • diagnostic approach
      • diagnosis is often based on clinical presentation followed by rule out of other causes of bowel obstruction  
    • imaging
      • abdominal radiograph 
        • best initial test
        • supine and upright views
        • positive findings may show dilated loops of bowel without a transition zone, air-fluid levels, and air in the colon and rectum
        • allows for rule out of other causes of abdominal pain (e.g., perforated viscus)
    • studies
      • laboratory studies are to be ordered given the clinical presentation to determine etiology/cause
      • electrolyte panel
        • hypokalemia and hypercalcemia may worsen ileus; hypomagnesemia can lead to hypokalemia
      • creatinine and blood urea nitrogen
        • uremia can lead to ileus
      • liver function tests, amylase, and lipase
        • pancreatitis may lead to ileus
      • thyroid panel
        • hypothyroidism may lead to ileus  
  • Mechanical bowel obstruction 
    • differentiating factors
      • physical examination will demonstrate high-pitched tinkling and history will often include colicky abdominal pain
  • Pancreatitis 
    • differentiating factors
      • although can lead to paralytic ileus, patients with pure pancreatitis will not have dilated bowels on imaging
  • First-line
    • supportive management
      • NPO or dietary restriction 
      • if severe, nasogastric suction with parenteral nutrition
      • IV fluids
    • address underlying etiology
      • remove offending medication if applicable
      • replace electrolytes
    • facilitate bowel movements
      • lactulose
      • erythromycin
      • neostigmine
        • for severe cases thought to have a neurological component (e.g., Oglivie syndrome)  
  • Perforation
  • Bowel necrosis/ischemia
  • Peritonitis
  • Hemodynamic instability
  • Death

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Questions (2)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2

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