MEDICAL CAUSES OF THE ACUTE

ABDOMEN

Dr. T.H De KlerkCritical 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 – C1-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

REFERENCES1. Farthing MJG. Pearls and Pitfalls in the Diagnosis of the

Acute Abdomen. Indian J Gastroenterol. 2006;25(1):33-35.

2. Cheng EH, Mills AM. Abdominal Pain in Special Populations. Emerg Med Clin N Am. 2011;29:449-458.

3. Ragsdale L, Southerland L. Acute Abdominal Pain in the Older Adult. Emerg Med Clin N Am. 2011;29:429-448.

4. Fields JM, Dean AJ. Systemic Causes of Abdominal Pain. Emerg Med Clin N Am. 2011;29:195-210.

5. Chang CC, Wang SS. Acute Abdominal Pain in the Elderly. Int J Gerontol. 2007 Jun;1(2):77-82.

6. 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.

7. Mueller PD, Beneowitz NL. Toxicologic Causes of Acute Abdominal Disorders. Emerg Med Clin N Am. 1989;7:667-682.

THANK YOU