Abdominal pain is a common presenting problem with multiple aetiologies that often pose diagnostic and therapeutic dilemmas for primary care practitioners. The vague symptomatology and difficult correlation to specific organ pathology obscures clinical findings leading to incorrect diagnoses. Although most presentations of abdominal pain are benign, a significant number of patients have life-threatening conditions that require a meticulous approach to management in order to prevent morbidity and mortality. The skill in assessing patients presenting with abdominal pain is fundamental for all primary care doctors. This review will discuss an approach to the assessment and diagnosis of abdominal pain in the primary care setting.
Abdominal pain is one of the most common complaints of patients admitted to emergency units, accounting for 5% – 10% of all presentations.
The diagnostic challenge facing primary care physicians regarding patients with abdominal pain, considering the spectrum of symptoms, diagnoses and management, presents a potential risk of delaying treatment for acutely ill patients.
This review seeks to provide an understanding of the pathophysiological basis and an approach to assessing the cause of abdominal pain in adults by primary care practitioners. Key aspects of history and physical examination will be discussed with the view to enhance appropriate and accurate assessments, management and early referral to higher levels of care.
Abdominal pain may originate from within the peritoneal cavity, the retro peritoneum, the pelvis, the abdominal wall or even from outside the abdomen. The physiological basis for intra-abdominal pain is listed in
Pathophysiology of abdominal pain.
Process | Example of disorders |
---|---|
Inflammation | Appendicitis; cholecystitis; pancreatitis; diverticulitis. |
Perforation | Perforated duodenal or gastric ulcer; biliary peritonitis. |
Obstruction | Acute small or large bowel obstruction; biliary or ureteric colic. |
Haemorrhage | Ruptured ectopic pregnancy; ruptured aneurysm or ovarian cyst; spleen. |
Torsion (ischaemia) | Sigmoid volvulus; torsion of testes; ovarian cyst. |
Pain receptors in the abdomen are stimulated by mechanical and chemical stimuli. Stretch is the primary mechanical stimulus whilst visceral mucosal receptors respond to chemical stimuli.
Localisation of visceral pain is ill-defined because of the type and density of visceral afferent nerves. The pain is usually perceived in the midline because most abdominal organs are innervated by afferent nerves from both sides of the spinal cord.
Mechanisms of abdominal pain.
Mechanism | Cause | Innervation | Nature | Location |
---|---|---|---|---|
Visceral | Inflammation, ischaemia, neoplasia and distension of either the wall of a hollow viscus, or the capsule of a solid intra-abdominal organ. | Afferent nerves from either side of the spinal cord | Colicky, cramp-like dull and burning, often with associated autonomic symptoms of nausea, vomiting, pallor and sweating. | Poorly demarcated; usually midline via autonomic fibres in the wall or capsule. Regional localisation to foregut, midgut and hindgut structures |
Parietal/somatic | Inflammation (bacterial or chemical) of the parietal peritoneum | Mediated by segmental nerves associated with specific dermatomes | Sharp aggravated by movement, coughing and breathing | Precise location to the structure of origin |
Referred | Infection, infarction, embolism, irritation; shares common embryological origin | Peripheral nerves sharing a common central pathway | Dull, aching perceived near the surface of the body; skin hyperalgesia. Increased muscle tone | Localised to a site distant to organ that is the source of pain |
Abdominal wall pain is frequently mistaken for intra-abdominal visceral pain with consequence of unnecessary investigations, imaging and procedures.
Abdominal wall pain comprises a number of aetiologies of which nerve entrapment, hernias and procedural complications are common.
Anterior cutaneous nerve entrapment syndrome is the most common and often passed-over type of abdominal wall pain.
The cornerstone of an accurate diagnosis is a detailed history that includes a full description of the patient’s pain and associated symptoms. The medical, surgical and social history may provide valuable information to aid assessment.
The PQRST mnemonic illustrated in
Pain assessment history.
Pneumonic | Pain assessment |
---|---|
P3 | Position, palliation and provoking factors |
Q | Quality |
R3 | Region, radiation and referral |
S | Severity |
T | Temporal factors (time and mode of onset, progression and previous episodes. |
The ‘PHRASED’ approach in gathering sufficient information is a useful guide to exploring the
In addition,
Key questions to ask in the history.
What type of pain is it: Is it constant or does it come and go?
How severe would you rate it from 1 to 10?
Have you ever had previous attacks of similar pain?
What else do you notice when you have the pain?
Do you know of anything that will bring on the pain? Or relieve it?
What effect does milk, food or antacids have on the pain?
Have you noticed any sweats or chills or burning of urine?
Are your bowels behaving normally? Have you been constipated or had diarrhoea or blood in your motions?
Have you noticed anything different about your urine?
What medications do you take?
How much aspirin do you take?
Are you smoking heavily or taking heroin or cocaine?
How much alcohol do you drink?
How much milk do you drink?
Have you travelled recently?
What is happening with your periods? Is it mid-cycle or are your periods overdue?
Does anyone in your family have bouts of abdominal pain?
Do you have a hernia?
What operations have you had for your abdomen?
Have you had your appendix removed?
It is important to consider the past medical history, as it will guide the possible cause of the abdominal pain. The important reminders are listed in
Past medical history reminders.
Depression | Thyroid disorder | UTI |
Diabetes | Spinal dysfunction | Herpes zoster |
Drugs | Anaemia | Pleurisy |
UTI, urinary tract infection.
Although the site of pain is important in identifying the source, visceral pain, referred pain or pain as a result of metabolic, toxic or psychological cause are not site dependent. Separating the abdomen into nine regions helps in describing the position of pain, tenderness, rigidity, tumours, et cetera. A summary of pathologies related to the anatomical regions of the abdomen is illustrated in
Anatomical localisation of pain.
A well-performed abdominal examination provides diagnostic clues regarding most gastrointestinal and genito-urinary pathologies decreasing the need for expensive radiological investigations.
It is important that all healthcare workers are skilled in performing a correct abdominal examination, understand significance of findings and correlate these with the history in order to formulate a diagnostic strategy and management plan.
This review does not provide a detailed discussion on abdominal examination.
The objectives of the abdominal examination includes assessment of the patient’s general condition, including a primary assessment, localisation of intra-abdominal pain and detection of extra-abdominal cause of pain.
The patient’s general appearance and vital signs will guide to the differential diagnosis. Patients with peritonitis tend to lie still, whilst those with renal colic seem unable to stay still.
Some often overlooked manoeuvres are useful in evaluating signs associated with the causes of abdominal pain. The Carnett’s sign – increased pain when a supine patient tenses the abdominal wall by lifting the head and shoulders off the examination couch is suggestive of abdominal wall pain.
In diagnosing abdominal pain, rectal and pelvic examinations are mandatory. A rectal examination may indicate faecal impaction, a palpable mass, or occult blood in the stool whilst tenderness and fullness on the right side of the rectum suggest a retrocaecal appendix.
Imaging and laboratory studies have significant images in the evaluation of acute abdominal pain and all diagnostic tests have a false negative rate.
The choice of laboratory investigations is therefore driven by the clinical situation to confirm differential diagnoses deduced from a good history and examination. These may include a Full Blood Count, inflammatory markers like C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), liver function tests, amylase and lipase, blood glucose, urine analysis, pregnancy test and faecal blood and arterial blood gas.
The main indications for plain x-rays include:
Intestinal obstruction
Perforated viscus
Foreign body
Renal/ureteric colic
Chest pathology
Ultrasound is widely used in the assessment of abdominal pain as it is non-invasive and has no radiation risk.
Urgent ultrasound scan is useful in the following situations:
Suspicion of abdominal aortic aneurysm
Suspicion of intra-abdominal abscess
Suspicion of cholelithiasis with right upper quadrant pain
Suspicion of urinary tract obstruction
Lower abdominal pain in fertile women
The use of algorithms can serve as a useful guide to approaching abdominal pain depending on the anatomical site of origin of pain. Vaghef-Davari et al. have developed several algorithms for the management of abdominal pain.
An illustration of the approach to generalised abdominal pain adapted from Vaghef-Davari et al. is shown in
Generalised abdominal pain algorithm.
The management of abdominal pain must be initiated simultaneously with assessment and investigations. Analgesia, fluid resuscitation, anti-emetics, nasogastric suction and antibiotics form the basis of most management plans, depending on the clinical findings following the history, examination and investigations.
Early appropriate analgesia reduces suffering and often aids in better co-operation of the patient in providing a better history and responses to examination. Opioid analgesia is not a contraindication and the previous injunction that it may mask the correct diagnosis of abdominal pain is unfounded.
A rapid diagnosis and immediate treatment are required for patients who may have life-threatening conditions,
Airway compromise with recurrent vomiting, or altered level of consciousness
Requiring oxygen and/or ventilation
Signs of circulatory failure.
After secondary assessment and emergency treatment, some patients with abdominal pain will require referral to the next level of care.
Indications to higher level of care include:
Suspected generalised tenderness
Suspected bowel obstruction
Tenderness with uncontrolled vomiting
Suspected pancreatitis
Suspected aortic aneurysm
Gastrointestinal bleeding
Associated mass
Severe pain with no confirmed cause
The authors declare that they have no financial or personal relationships that may have inappropriately influenced them in writing this article.
I.G., S.R., T.B. and P.M. contributed equally to the article.
The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of any affiliated agency of the authors.