Diverticulitis - Gastrointestinal

Snapshot
A 63-year-old female is brought to the emergency room for severe abdominal pain for the past 1 day. She reports that the pain is 9/10, dull, with intermittent exacerbations concentrated at the left lower quadrant (LLQ). She endorses low-grade fever, nausea, and vomiting for the past couple of hours. Her past medical history includes hypertension, constipation, and diverticulosis. A physical examination demonstrates abdominal tenderness and some diffuse voluntary guarding.
Introduction
Clinical definition gastrointestinal disease characterized by the inflammation of diverticula results from a microscopic or macroscopic perforation of a diverticulum due to diverticular inflammation and focal necrosis patients can present with repeated attacks complicated diverticulitis is defined as diverticulitis with 1 of the following associated complications bowel obstruction abscess fistula perforation Epidemiology demographics most commonly occurs at the sigmoid colon in North America, reflecting the distribution of diverticulosis right-sided (cecal) diverticulitis is more common in Asian populations approximately 4% of patients with diverticulosis develop acute diverticulitis risk factors obesity lack of exercise smoking positive family history nonsteroidal anti-inflammatory drugs (NSAIDs) Pathogenesis primary process is thought to be due to erosion of the diverticular wall by increased intraluminal pressure or inspissated food particles erosions of the wall then lead to inflammation and focal necrosis that may lead to micro- or macroscopic perforation the inflammation is frequently mild and often walled off by pericolic fat and mesentery this may lead to the formation of a localized abscess or a fistula (if adjacent organs are involved) poor containment of the inflamed diverticulum or abscess can result in free perforation and peritonitis
Presentation
Symptoms abdominal pain most commonly at the LLQ nausea vomiting constipation diarrhea Physical exam fever hypotension tender mass peritoneal signs (e.g., guarding, rigidity, and rebound tenderness)
Studies
Diagnostic testing diagnostic approach diagnosis is based on clinical presentation and is confirmed via imaging studies imaging computed tomography (CT) with oral and IV contrast best diagnostic test positive findings include localized wall thickening (> 4mm), pericolic fat stranding, and presence of colonic diverticula also allows for visualizations of complications such as abscess, obstruction, or perforation abdominal ultrasound indicated in patients who cannot receive radiation positive findings include bowel wall thickening, hypoechoic peridiverticular inflammatory reaction, and the presence of diverticula abdominal and chest radiographs may be useful in detecting pneumoperitoneum and obstruction positive findings include air-fluid levels with bowel dilation or free air colonoscopy not to be performed during acute diverticulitis for risk of perforation recommended 4-6 weeks after resolution for evaluation and rule out of malignancy studies complete blood count may see leukocytosis urinalysis may see sterile pyuria or colonic flora (if colovesical fistula) pregnancy test indicated in all women of childbearing age
Differential
Inflammatory bowel syndrome (IBD) differentiating factors will often present with more chronic clinical symptoms and will have positive biopsy findings Colorectal cancer differentiating factors will be visualized on colonoscopy Acute appendicitis differentiating factors will appear differently on abdominal CT imaging
Treatment
Management depends on disease severity, certain characteristics, and the presence of complications the majority of patients with acute diverticulitis can be treated with medical management Outpatient treatment indicated for patients with uncomplicated diverticulitis and no signs of high fever, significant leukocytosis, peritoneal signs, sepsis, immunosuppression, advanced age, intolerance of oral intake, or significant comorbidities oral antibiotics for 7-10 days with following 2-3 days after first visit Inpatient medical management IV antibiotics with transition to oral antibiotics with improvement IV fluids Parenteral pain medications NPO if unable to tolerate oral intake Surgery indicated for patients with perforated diverticulitis, hemodynamic instability, or peritonitis can be offered electively to patients with recurrent or chronic symptoms, patients who are immunosuppressed or with a prior episode of complicated diverticulitis
Complications
Abscess should be suspected in patients with uncomplicated diverticulitis showing no improvement despite 3 days of antibiotic treatment if < 3cm, then treat with IV antibiotics if > 3cm, consider CT-guided percutaneous drainge Bowel obstruction Diverticular fistula Perforation Peritonitis Shock

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

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
Volume
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
Urine
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