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  • A 61-year-old man presents to the clinic for an annual wellness exam. He denies any specific concerns except for some constipation for the past week. His past medical history is significant for hypertension that is controlled with lisinopril. He denies fever, weight changes, melena, hematochezia, abdominal pain, or stool changes. He subsequently undergoes a routine colonoscopy which demonstrates small outpouchings within the sigmoid colon.
  • Clinical definition
    • condition of having multiple sac-like protrusions (diverticula) of the colonic wall that are not inflamed
      • these diverticula can cause painless bleeding
    • diverticulitis is defined as inflammation of a diverticulum 
  • Epidemiology
    • demographics
      • prevalence increases with age with a prevalence of 60% by age 60
      • location of the diverticula varies by geography
        • sigmoid colon is the most common location in Western countries
        • predominately at the right side in Asian countries
    • risk factors
      • age
      • low dietary fiber
      • high fat and red meat intake
      • physical inactivity
      • obesity
  • Pathogenesis
    • abnormal colonic motility leading to the colonic mucosa and submucosa to herniate through well-defined points of weakness at the muscle layer 
      • points of weakness correspond to where the vasa recta penetrate the circular muscle layer of the colon
      • a typical colonic diverticulum is a “false diverticulum” and is only covered by serosa
    • it is hypothesized that abnormal colonic motility causes increases in intraluminal pressure
    • diverticular bleeding occurs due to segmental weakness of the vasa recta, as it is exposed to injury along its luminal aspect from the diverticulum
  • Symptoms 
    • asymptomatic  
    • cramping
    • bloating
    • flatulence
    • irregular defecation
    • rectal bleeding
  • Physical exam
    • left lower quadrant (LLQ) pain and tenderness
  • Diagnostic testing
    • diagnostic approach
      • diagnosis is often incidental during other investigations and is confirmed via colonoscopy
    • imaging
      • colonoscopy 
        • gold standard
        • allows for visualization of diverticula and rule out of differential (e.g., malignancy)
        • not recommended during an acute diverticulitis attack
      • computed tomography (CT) with contrast
        • best for the evaluation of acute diverticulitis  
      • plain abdominal radiograph
        • may show signs of constipation
        • rules out other causes of abdominal pain (e.g., small bowel obstruction)
    • studies
      • laboratory studies
        • CBC and iron studies for evaluation of anemia secondary to blood loss
  • Diverticulitis
    • differentiating factors
      • will present clinically with severe abdominal pain and fever
  • Colon/rectal cancer 
    • differentiating factors
      • may complain of symptoms (e.g., stool changes) and the lesion will be present on colonoscopy
  • As diverticulosis often presents asymptomatically, no specific treatment is needed
  • First-line
    • observation
    • lifestyle changes 
      • high-fiber diet to prevent constipation
  • In the case of diverticular bleeding 
    • resuscitation (e.g., IV fluids and blood products)
    • colonoscopy with cauterization
    • if bleeding is not identified with colonoscopy, then angiography is indicated
    • surgery is the last resort if the bleeding cannot be controlled with colonoscopy or angiography 
  • Anemia
  • Bleeding/hemorrhage
  • Exsanguination
  • Diverticulitis

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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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