GI Flashcards
Define peritonitis
Inflammation of the serosal membrane that lines the abdominal cavity and the organs contained therein
Describe causes of peritonitis
Usually sterile, reacts to chemical and mechanical stimuli. Abdominal infection can be peritonitis (generalised infection) or intra-abdominal abscess (localised).
Infection usually after perforation of an organ, but can be due to foreign bodies, bile acids or stomach acid entering the space.
Define classifications of peritoneal infection
- Primary: from haematogenous dissemination/bacteria across gut wall, usually in the setting of an immunocompromised state. Most often spontaneous bacterial peritonitis, seen mostly in patients with chronic liver disease
- Secondary: related to a pathologic process in a visceral organ, such as perforation or trauma, including iatrogenic trauma. The most common form of peritonitis encountered in clinical practice
- Tertiary: persistent or recurrent infection after adequate initial therapy. Often develops in the absence of the original visceral organ pathology. Usually immunocompromised individuals. TB peritonitis is a problem among HIV+ve individuals.
How is peritonitis diagnosed?
Usually clinical
Peritoneal lavage if non-conclusive signs/history not available
Need to find cause it secondary peritonitis (erect CXR for free gas, CT scan, amylase, lipase, bilirubin, ALP, lactate, ß-HCG, urinalysis, stool culture, toxin assays)
Describe pathophysiology of secondary peritonitis
- Secondary peritonitis results from direct spillage of luminal contents into the peritoneum (eg, perforated peptic ulcer, diverticulitis, appendicitis, iatrogenic perforation)
- With the spillage of the contents, gram-negative and anaerobic bacteria, including common gut flora, such as E. coli and Klebsiella pneumoniae, enter the peritoneal cavity
- Endotoxins produced by gram-negative bacteria lead to the release of cytokines that induce cellular and humoral cascades, resulting in cellular damage, septic shock, and multiple organ dysfunction.
- Usually polymicrobial if colonic rupture
Signs and symptoms of peritonitis
- Fever and chills (80%) (>38º, <36º)
- Abdominal pain or discomfort (70%) (dull and poorly localized-> more severe and more localized. Worse with movement and local pressure. Patients on steroids, with diabetic neuropathy and extremes of age may present with less pain)
- Worsening or unexplained encephalopathy
- Diarrhea
- Ascites that does not improve following administration of diuretic medication
- Worsening or new-onset renal failure
- Ileus
What Qs need to be asked with a pt presenting with ?peritonitis
- Recent abdominal surgery
- Previous episodes of peritonitis
- Travel history
- Use of immunosuppressive agents
- Presence of diseases (eg, inflammatory bowel disease, diverticulitis, peptic ulcer disease) that may predispose to intra-abdominal infections
- Anorexia and nausea
Differentials to peritonitis
- Chemical irritation
- Thoracic processes with diaphragmatic irritation (eg, empyema)
- Extraperitoneal processes (eg, pyelonephritis, cystitis, acute urinary retention)
- Abdominal wall processes (eg, infection, rectus hematoma)
- External hernias (rule out intestinal incarceration)
- Gynae conditions (chlamydia peritonitis, teratoma, salpingitis)
- Parasitic infections
- Vascular conditions (mesenteric embolus, ischaemic colitis)
Treatment of peritonitis
- Find cause (if primary, parecentesis, drain and irrigate)
- MC&S with pH (see if faecal contents or bile)
- Broad spectrum abx
- Drain abscess
- Laparotomy?
What are the causes of pancreatitis?
GET SMASHED Gall stones (38%) Ethanol (35%) Trauma (1.5%) Steroids Mumps Autoimmune Scorpion bites (Trinidad) Hyperlipidaemia, hypothermia, hypercalcaemia ERCP and emboli Drugs
How many people have unexplained pancreatitis?
10-30%
Mortality of pancreatitis
12%
How does pancreatitis cause mortality?
Oedema and fluid shifts-> hypovolaemia
Fluid trapped in gut, peritoneum, retroperitoneum
Enzyme mediated autodigestion -> necrosis and infection
Protease induced coagulation cascade, complement activation, kinin, fibrinolytic cascade, oxidative stress
Signs and symptoms of pancreatitis
Symptoms: • Severe epigastric pain/central abdo pain • Pain radiates to back, relieved by sitting forward • Vomiting Signs: • Tachycardia • Fever • Jaundice • Shock • Ileus • Rigid abdomen • Periumbilical bruising (Cullen’s) and flank bruising (Grey Turner’s) due to blood vessel autodigestion and retroperitoneal haemorrhage
Differential diagnoses to pancreatitis
- Perforated duodenal ulcer
- Mesenteric infarction
- MI
What is the modified glasgow score?
Assesses severity and predicts mortality
Valid for alcohol and gallstones
What are the sections of the modified glasgow score?
PANCREAS PaO2: <8 Age: >55 Neutrophils: >15 Ca2+: <2 Renal function: Urea>16 Enzymes: LDH>600, AST>200 Albumin: <32 Sugar: >10
What investigations need to be carried out in pancreatitis?
FBC: WCC raised
Raised amylase (>1000) and raised lipase
U&E: dehydration and renal failure
LFT: cholestatic picture (raised AST and LDH)
Low calcium, raised glucose
CRP: raised if severe (>150)
ABG: hypoxia if respiratory distress
Urine: glucose, conjugated bilirubin, decreased urobilinogen
CXR: exclude perforated duodenal ulcer, ARDS?
AXR: pancreatic calcification?
USS: Gallstones, dilated pancreatic ducts, inflammation
Contrast CT (look for pancreatic necrosis)
Management of pancreatitis
- Hourly obs and urine output
- IV fluids! Until UO>30ml/hr
- Pancreatic rest (nil by mouth, NG tube if vomiting, TPN to prevent catabolism)
- Analgesia (PETHIDINE/MORPHINE)
- Laparotomy and debridement
- ERCP and gall stone removal if progressive jaundice
Complications of pancreatitis
- Shock, ARDS, renal failure, DIC, sepsis, hyperglycaemia, hypocalcaemia
- Pancreatic necrosis and pseudocyst
- Abscess, bleeding, thrombosis, fistulae
Main causes of chronic pancreatitis
Chronic pancreatitis:
70% alcohol
Genetic (CF, HH), Immune, Raised triglycerides, Structural (obstruction by tumour/pancreatic divism)
Signs & symptoms of chronic pancreatitis
Pain exacerbated by alcohol/fatty food Relieved by sitting back or hot water bottle Steatorrhoea and weight loss Diabetic signs (olyuria, polydipsia) Epigastric mass (pseudocyst)
