MEDICAL CAUSES OF THE ACUTE ABDOMEN Dr T

MEDICAL CAUSES OF THE ACUTE ABDOMEN Dr. T. H De Klerk Critical Care 12 May 2014

DEFINITION • The term, acute abdomen, is the medical slang word that denotes an acute, serious abdominal condition, usually treated best by surgical operation. • More appropriately referred to as a “surgical abdomen”.

EPIDEMIOLOGY • Acute abdominal pain comprises 5% of all emergency medicine consultations (USA) • 18 -25% of these patients are admitted to hospital • 10% of those admitted require surgery • 8% of admissions are purely medical cases

ANATOMY AND PHYSIOLOGY • Visceral pain – poorly localised to mainly the midline • Parietal pain - better localised to a dermatomal distribution • Referred pain – certain structures share central pathways due to their specific embryonic development • Central pain – from thalamic and cortical structures

HISTORY • Time course – hyperacute (seconds), acute (minutes) and gradual (hours) • Location – often misleading, e. g. cholecystitis • Radiation, exacerbating and relieving factors and associated symptoms • Surgical conditions- pain generally preceeds vomiting • Non-surgical conditions – vomiting generally preceeds pain • Fever, vomiting, diarrhoea, leucocytosis are unhelpful

BACKGROUND • Risk factors, e. g. DM, HPT, vascular or cardiac disease • Previous surgical procedures - risk for obstruction • Previous similar episode (consider medical cause) • Familial disease • Age group specific diseases, e. g. appendicitis in the young, or diverticulitis in the elderly

CLINICAL EXAMINATION • Must be seen in the context of patient’s history and risk factors • 2004 Israel study: more than 600 patients evaluated for acute abdomen clinically vs CT diagnosis 37% correlation between the groups, 8% of patients underwent surgery unnecessarily due to incorrect diagnosis • The art of the abdominal examination: time very important, recurrent re-evaluation • Abdominal x-rays: dilated bowel loops, intra-peritoneal air • Abdominal ultrasound & CT scan: confirm diagnosis and plan further management

CATEGORIES OF MEDICAL CAUSES • Referred pain – adjacent structures • Lung: pneumonia, pleuritis, pulmonary embolus/infarct, empyema, pneumothorax • Heart: myocardial infarction, myocarditis, pericarditis, congestive cardiac failure • Oesophagus: oesophagitis, spasm, rupture • Pelvis: PID, ovarian/testicular torsion, follicular rupture, ovarian hyperstimulation syndrome

MEDICAL CAUSES CONTINUED • Metabolic • Adrenal insufficiency – gastric dysmotility, serositis • DKA - gastritis, gastric distension, ileus • Thyrotoxicosis – unknown, probably ileus • Porphyria – visceral autonomic neuropathy • Hypercalcaemia – ileus, increased gastrin which leads to gastritis, pancreatitis, ureterolithiasis • Hyperlipidaemia – pancreatitis • Uraemia – ileus, gastritis • Haemochromatosis - SBP

MEDICAL CAUSES CONTINUED • Infection • Toxins – tetanus, botulism • Dysentry – shigella, salmonella, campylobacter, amoebiasis • Severe gastroenteritis – giardiasis, isospora belli • Mesenteric lymphadenitis – yersinia, extrapulmonary TB, CMV • Infestations – helminths, schistosomiasis, obstruction • Infiltration – malaria, EBV • Translocation - SBP

MEDICAL CAUSES CONTINUED • Vascular • Arterial – mesenteric ischaemia and infarction, dissection (abdominal pain out of proportion to clinical findings) • Vasculitis – large vessel: Takayasu, medium vessel: PAN, small vessel: Wegeners • Coagulopathy – arterial and/or venous thrombosis, primary e. g. APLS, secondary e. g. malignancy • Specific vascular syndromes, e. g. Budd -Chiari, portal vein thrombosis

MEDICAL CAUSES CONTINUED • Haematological • Acute leukaemia, lymphoma – infiltration, tumour necrosis • Haemolytic anaemia, Sickle cell anaemia, polycythaemia vera – vascular spasm and/or thrombosis • Haemophilia – abdominal wall haematomas

MEDICAL CAUSES CONTINUED • Drugs and toxins • Mucosal irritants and corrosives – iron, mercury, NSAIDs • Ileus – anticholinergics, narcotics (opioid bowel syndrome) • Bowel ischaemia – cocaine, amphetamines, ergotamines • Heavy metals – lead, arsenic • Biological – black widow spider: hyperstimulation of NMJ

MEDICAL CAUSES CONTINUED • Neurological • Central – abdominal migraine, abdominal epilepsy, • Neuropathies – tabes dorsalis, secondary to syphilis. Radiculopathy: degenerative spine disease, disc herniation, post-herpetic neuralgia

MEDICAL CAUSES CONTINUED • Miscellaneous • Lactose intolerance • Eosinophillic gastroenteritis • SLE – pancreatitis, serositis, vasculitis • Periodic fever syndromes • Radiation enteritis • Glaucoma • Angioedema – C 1 -esterase inhibitor deficiency, ACE inhibitors

SPECIAL POPULATION GROUPS • Pregnancy – abdominal examination difficult, uterus obscures rest of abdomen • Neurological disease – no pain sensation, quadroparesis, inability to communicate – delirium, dementia • ICU patients – altered pain perception, 38% of patients with peritonits have peritoneal signs. Consider acalculus cholecystitis • Post-procedural patients • vena cava filters which migrate, fracture, thrombose etc • PEG tubes – peri-stomal leakage • Biopsies – subcapsular haematoma

• Immunocompromised • Blunted inflammatory response • Organ transplants lack nerve innervation • Opportunistic infections, e. g. PCP, CMV • Weakening of connective tissue, e. g. corticosteroids and bowel wall perforation • Drugs: ARV’s (pancreatitis, lactic acidosis), Chemotherapeutic agents, e. g. vincristine • Neutropenic enterocolitis (typhlitis)

• Elderly patients • Immunosenescence – decreased immunosurveillance, decreased antibodies and T cells, decreased pyrogen response • GI tract – decreased motility and secretion • CNS – dementia, delirium, decreased peripheral sensation • Increased amount of chronic diseases • Increased drug usage – decreased pain and sympathetic response, increased drug interactions, e. g. digoxin toxicity

REMEMBER… • An atypical presentation of a common condition is much more likely than the typical presentation of an uncommon condition

REFERENCES 1. 2. 3. 4. 5. 6. 7. Farthing MJG. Pearls and Pitfalls in the Diagnosis of the Acute Abdomen. Indian J Gastroenterol. 2006; 25(1): 3335. Cheng EH, Mills AM. Abdominal Pain in Special Populations. Emerg Med Clin N Am. 2011; 29: 449 -458. Ragsdale L, Southerland L. Acute Abdominal Pain in the Older Adult. Emerg Med Clin N Am. 2011; 29: 429448. Fields JM, Dean AJ. Systemic Causes of Abdominal Pain. Emerg Med Clin N Am. 2011; 29: 195 -210. Chang CC, Wang SS. Acute Abdominal Pain in the Elderly. Int J Gerontol. 2007 Jun; 1(2): 77 -82. Gajic O, Urrutia LE, Sewani H, Schroeder DR, Cullinane DC, et al. Acute Abdomen in the Medical Intensive Care Unit. Crit Care Med. 2002; 30(6): 1187 -1190. Mueller PD, Beneowitz NL. Toxicologic Causes of Acute Abdominal Disorders. Emerg Med Clin N Am. 1989; 7: 667 -682.

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