Acute Abdomen Flashcards
What is the definition of an acute abdomen?
Recent or sudden onset of unexpected signs or symptoms, including abdominal pain.
Potential for life-threatening infection or fluid/blood loss
Reminder: what are the features of visceral pain?
Stimulation of receptors in smooth muscle by:
- ischaemia
- distension/stretching
- tension
Often colicky.
Conducted by ANS.
Poorly localised to midline.
Associated with malaise, N&V, and sweating.
Reminder: what are the features of somatic pain?
Stimulation of pain receptors in parietal peritoneum.
Conducted by segmental somatic nerves.
Accurately localised.
Usually overrided by the early visceral component.
Give some examples of causes of generalised and localised peritonitis.
Generalised peritonitis:
- perforated viscus
- primary infective peritonitis
- rupture of cyst
Localised peritonitis:
- appendicitis
- cholecystitis
- pancreatitis
- diverticulitis
- abscesses
- salpingitis/ruptured ectopic pregnancy
Give some examples of causes of ischaemia in the acute abdomen.
- mesenteric angina
- splenic infarction
- torsion of ovarian cyst/testicle/omentum
- tumour necrosis (hepatoma, fibroid)
Give some examples of extra-abdominal causes of acute abdomen.
Thoracic: pleurisy, pneumonia, IHD, oesophageal disease
Neurological: herpes zoster, spinal arthritis, radiculopathy from tumours, tabes dorsalis, abdominal epilepsy
Metabolic: diabetes mellitus (DKA), chronic renal failure, porphyria, acute adrenal insufficiency
Toxins: snake/insect bites, lead poisoning, strychnine
Other: peptic ulcer, IBD
What are the key questions for assessing the acute abdomen?
Severity
Character:
- ?colicky
- sharp, severe, well localised or dull, vague, deep
Location:
- ?localised to quadrant
- ?midline
- ?radiation of pain
Aggravating/relieving factors:
- diffuse peritonitis
- colic due to bowel obstruction
Urinary features:
- frequency
- urgency
- pain
- haematuria
Gynae features:
- last menstrual period
- discharge
GI features:
- appetite
- N&V
- distension
- bowel habit changes
- weight loss
- blood/mucus in stool
History of trauma
Past medical and surgical history:
- clotting/blood disorders
- cancer (abdo. mets)
- previous abdominal surgery (adhesions)
- previous surgery (?anaesthesia reaction)
Medications/allergies
FHx:
- bowel cancer
- hereditary disorders
- anaesthetic problems
SHx:
- alcohol (detox, gastritis, cancer, liver disease)
- recreational drugs
- smoking (cancer, increased coagulation, peptic ulcers)
- diet
- occupation
- carers
- living arrangement
- exercise
Systems r/v:
- cancer
- cardiorespiratory
- GU (?pregnancy)
- urinary (?UTI)
Last meal: Nil by mouth
Compare the differentials of acute abdomen according to timeframe.
Sudden (secs):
- perforation/rupture of AAA/duodenal ulcer
- MI
- acute mesenteric occlusion
Rapidly accelerating (min):
- biliary colic
- ureteric colic
- small bowel obstruction
Gradual (hrs):
- inflammatory
- obstructive
- mechanical
What are the time limits for nil by mouth?
Food - 6hrs
Breast milk - 4hrs
Clear liquids - 2hrs (non-fizzy to prevent reflux and regurgitation)
What are the features of acute abdomen caused by malignancy?
Intermittent pain lasting >48hrs
Alteration of bowel habit
Mass felt
Weight loss
Abdominal distension
What are the features of acute abdomen caused by intestinal obstruction?
Colicky severe pain
No aggravating factors
Vomiting/constipation (depending on level of obstruction)
Abdominal distension
High pitched bowel sounds
Previous surgery
What are the features of acute abdomen caused by a perforated viscus?
Sudden onset of pain
Constant severe pain
Pain aggravated by moving/coughing
Diffuse tenderness
Silent, rigid abdomen
What are the key examinations in an acute abdomen?
- ABCDE
- bedside: vomit bowls, IVs, Abx
- general: appearance (unwell, pain, consciousness), vital signs (obs chart, EWS)
- abdo. inspection: distension, discolouration (rashes, Grey Turner’s/Cullen’s, erythema ab igne), scars, visible peristalsis, masses (hernias, tumours, varices)
- abdo. palpation: light (?tenderness), deep (?masses), guarding/rigidity (peritonitis), palpable masses, hernial orifices, rebound tenderness (peritonitis releasing stretches peritoneum)
- abdo. percussion
- abdo. auscultation: bowel sounds (peritonitis causing ileus has no bowel sounds, obstruction has tinkling bowel sounds)
- PR +/- PV, testicles: PID, testicular torsion, indirect inguinal hernia, bowel obstruction, rectal bleeding
- systems r/v: cardiorespiratory, vascular
What are the key investigations in an acute abdomen?
- Bedside: BM, urinalysis, pregnancy test, temperature, spO2, BP +/- stool samples +/- ECG
- FBC: anaemia, infection
- Clotting: DIC (sepsis), drugs, liver pathology
- G&S: identify blood type and cross-match
- U&Es: hypokalaemia (vomiting), renal function
- amylase (serum/urinary): pancreatitis
- ABG: acid-base balance, lactate
- CRP
- CXR: bowel perforation
- AXR: obstruction (dilated bowel)
- US
- contrast studies
- CT scan: perforation
- laparoscopy/(exploratory) laparotomy
What is the general management of an acute abdomen?
- NBM
- IV fluids (dehydration)
- ?frequency of observations
- tubes: catheter (monitor fluid output), NG (vomiting, obstruction)
- thromboprophylaxis: TEDs, dalteparin (VTE assessment)
- analgesia (IV morphine)
- antiemetics
- ?Abx
- theatre workup (bloods, ECG, put on theatre list)
Reminder: what are the different regions of the abdomen according to the digestive tract?
EPIGASTRIC:
Stomach —> 2nd part of duodenum
Liver/biliary tree
Pancreas & spleen
PERIUMBILICAL:
2nd part of duodenum —> proximal 2nd-3rd of transverse colon
SUPRAPUBIC:
Distal transverse colon to anal verge
What is the aetiology of acute appendicitis?
1/400 incidence Peak incidence 15-25yrs Majority of appendices are retrocaecal (63%) - 33% vermiform - pre- and post-ileal - subcaecal - paracaecal
Describe the pathophysiology of acute appendicitis.
Causes of lumen obstruction:
- faecolith
- foreign body
- tumour
- trichobezoar
- worms
- trauma
- lymphadenitis
Inflammation —> increased intraluminal pressure/onbstruction —> lymphoid swelling, decreased venous drainage, thrombosis, bacterial invasion —> abscess —> gangrene —> perforation —> peritonitis
What are the signs and symptoms of acute appendicitis?
- severe constant pain; starts as diffuse periumbilical pain and then moves to McBurney’s point
- fever
- unwell; flushed
- anorexia
- N&V
- lymphadenopathy (mesenteric adenitis)
- diarrhoea
Constrat the prevalence of diagnoses of acute abdomen.
- nonspecific (34%)
- mesenteric adenitis = children following infection
- acute appendicitis (28%)
- acute cholecystitis/biliary colic (10%)
- peptic ulcer perforation/bleeding (4%)
- small bowel obstruction (4%)
- gynaecological cause (4%) = ovarian cyst rupture/torsion, PID, ectopic, dysmenorrhoea
- acute pancreatitis (3%)
- renal/ureteric colic (3%)
- malignant disease (2%)
- acute diverticulitis (2%) = usually left-sided (sigmoid) but can be right-sided if bowel is long and looping
- dyspepsia (1%)
- IBD = “fat-wrapping” around affected bowel
What is the scoring system for acute appendicitis diagnosis?
MANTRELS
Migratory pain +1 Anorexia +1 Nausea +1 Tenderness (RIF) +2 Rebound tenderness +1 Elevated temp. +1 Leucocytosis +2 Shift to left (blood film; indicates neutrophilia) +1
7 or above indicates acute appendicitis diagnosis
What is Rovsing’s sign?
Light palpation of LIF causes pain in the RIF caused by displacement of appendix against peritoneum.
Specific to appendicitis
What is psoas sign?
Patient lies on left side —> hyperextend right thigh —> abdo. pain as iliopsoas contracts
e.g. inflamed appendix lying near iliopsoas, extrapelvic abscess
What are some of the investigations which may be appropriate in acute appendicitis?
BEDSIDE: BP, bpm, spO2, urine dip. (leucocytes)
BLOODS:
- U&Es: dehydration
- FBC: thrombocytosis, leucocytosis, anaemia
- pregnancy
- CRP
- INR
- G&S
- blood culture
IMAGING:
- CXR: ?perforation
- US: if female to check repro. tracts before op.
- abdo. CT
- AXR: ?bowel obstruction
What are the sepsis six?
- Deliver high flow O2
- Take blood cultures
- Empirical IV Abx
- Measure serum lactate & FBC
- IV fluid resuscitation
- Commence accurate urine output measurement
What is the management of acute appendicitis?
- ABCDE: 3.0-3.5l of Hartmann’s/saline over 24hrs
- book OR for open/diagnostic lap +/-/appendicectomy
- anaglesia: morphine, IV paracetamol
- NBM
- DVT prophylaxis: dalteparin
- ?Abx: can complicate diagnosis unless sepsis is diagnosed
- monitoring
- senior review
- laparoscopy
When is an open appendicectomy indicated?
- suspicion of adhesions
- young (small abdomen)
- difficult access
- surgeon incapable of lap. appendicectomy
Should the appedix be removed in an appendicectomy if it looks normal?
Yes
- prevent future appendicitis
- microscopic inflammation
Give some extramural causes of intestional obstruction.
- adhesions, fibrous bands
- herniae (internal and external)
- compression by tumour e.g. ovarian, peritoneal metastases
Give some intramural causes of intestinal obstruction.
- IBD
- tumours e.g. adenocarcinoma, lymphoma, carcinoid
- structures e.g. IBD, colitis, surgery (anastomosis), diverticular, ischaemia
- volvulus
- intussusception (adults: adhesions, strictures; babies: Henoch-Schonlein purpura, enlarged lymph nodes)
Give some intraluminal causes of intestinal obstruction.
- faecal impaction
- swallowed foreign bodies
- bezoars
- gallstone ileus
What are the most common causes of small intestinal obstruction?
Adhesions (50%-75%) = fibrous tissue usually resulting from prev. surgery causes “kinks” in bowel
Hernias (7%-25%)
- femoral = high risk of strangulation (sharp, tough, borders —> venous swelling —> incarceration)
- inguinal = low risk of strangulation
Give some causes of functional obstruction of the intestines.
- paralytic ileus following surgery/electrolyte imbalance
- pseudocolon: elderly, mental disorders, electrolyte imbalance
- Hirschsprung’s disease
What are the less common causes of small intestinal obstruction?
Primary malignancy: GIST, carcinoid syndrome, lymphoma, caecal carcinoma
Seconday malignancy: ovarian, colorectal, stomach; causes multiple level obstruction (surgery not indicated —> permanent ileostomy)
Volvulus around fibrous band adhesion —> closed-loop —> fluid moves in —> distension
Mesenteric infarction
Gallstone ileus
Intussusception
