Emergency Abdominal Pain

Introduction

Abdominal pain is a common outpatient presentation which is challenging to diagnose.¹Cartwright SL, Knudson MP. Evaluation of acute abdominal pain in adults. Am Fam Physician. 2008; 77(7):971-978.   It is the most common cause of hospitalisation in the United states and is responsible for 5% to 10% of all emergency department visits. Out of all the hospitalisations for abdominal pain, 35% to 40% have a nonspecific pain. Acute abdominal pain is a term used to describe acute condition within the abdomen that requires immediate medical or surgical attention. Acute abdominal pain may sometimes not be of abdominal origin and may or may not require surgery.²Karnath B, Milenski W. Acute abdominal Pain. Hospital Physician 2002; 45-50.  

Epidemiology

The most common cause of abdominal pain which does not require surgery is gastroenteritis. On the other hand, the most common cause of abdominal pain which requires surgery is appendicitis. In older patients (>60 years), the most common cause of acute abdominal pain are biliary disease and intestinal obstruction. In younger patients, however, acute appendicitis is the most common cause of acute abdominal pain accounting for 25% of cases. In children acute appendicitis is the common cause of acute abdominal pain accounting for 32% admissions in the hospital.²Karnath B, Milenski W. Acute abdominal Pain. Hospital Physician 2002; 45-50.  

Aetiology

Acute abdomen pain may be caused by a variety of factors. The most common causes of acute abdominal pain are appendicitis, biliary colic, cholecystitis, diverticulitis, bowel obstruction, visceral perforation, pancreatitis, peritonitis, salpingitis, mesenteric adenitis and renal colic (Table 1). Less common causes of acute abdominal pain include hepatoma necrosis, splenic infarction, myocardial infarction, diabetic ketoacidosis, inflammatory aneurysma, sigmoid, caecum or stomach volvulus and a manifestation of herpes zoster.³Abdullah M, Firmansyah M. Diagnostic approach and management of acute abdominal pain. The Indonesian journal of Internal Medicine 2012; 44(4): 344-350.  

Table 1: Common causes of acute abdominal pain⁴Murtagh J. Acute abdominal pain: A diagnostic approach. Aust Fam Physician 1994:23; 358-61.  

Patient History

Acute abdominal pain usually involves a sudden onset of pain and surgical resection is the likely course of action. Apart from the age of the patient, it is necessary to understand the time of pain, location and character of pain and pattern of pain radiation. The presence of nausea, vomiting and bowel habits should be considered. The menstrual history of female patients should also be considered.²Karnath B, Milenski W. Acute abdominal Pain. Hospital Physician 2002; 45-50.  

Age

Differential diagnosis of acute abdomen pain in child is different from that of an adult. However, some conditions like acute appendicitis, intestinal obstruction and incarcerated hernias are common in all groups. However, in adults, adhesions are more likely to cause intestinal obstruction whereas; intussesception is a more likely cause of intestinal obstruction in children.

Time of onset

A sudden onset of pain that awakens the patient from sleep is suggestive of a perforated viscous. The timing of the nausea and vomiting narrows down the possible diagnosis. When the abdominal pain is from surgically correctable causes, pain is preceded by vomiting, while the reverse is true for medically treatable conditions like gastroenteritis.

Location

The abdomen is divided into 4 quadrants (Figure 1). These are further divided into epigastric, preumbilical and suprapubic regions. Right upper quadrant pain usually occurs from duodenal ulcers, acute pancreatitis, acute cholecystitis and acute hepatitis. Left upper quadrant pain usually occurs from gastritis, gastric ulcers, acute pancreatitis and splenic infarct or rupture. Right lower quadrant pain usually occurs from acute appendicitis. Left lower quadrant pain usually occurs from diverticulitis. Lower quadrant pain can also occur due to gynaecological and urological aeitiologies.

Figure 1. Adobminal section. (A) the 4 abdominal quadrants. (B) The epigastric, umbilical and superapublic (hydrogastric) region. LLQ = left lower quadrant; LUQ = left upper quadrant; RLQ = right lower quadrant; RUQ = right upper quadrant.²Karnath B, Milenski W. Acute abdominal Pain. Hospital Physician 2002; 45-50.  

Character

The character of the pain is usually suggestive of the quality of the pain that the patient describes. The pain defined may be sharp, dull or colicky. Colicky pain is defined as a rhythmic pain resulting from intermittent spasms. Colicky abdominal pain is most commonly associated with biliary disease, nephrolithiasis, and intestinal obstruction. Pain that starts as a poorly localised ache and progresses into a constant, well localised sharp pain is usually suggestive of a surgical correctable origin. A classic example of this type of pain associated with acute appendicitis.²Karnath B, Milenski W. Acute abdominal Pain. Hospital Physician 2002; 45-50.  

Differential Diagnosis

The physician should consider both the common conditions and more serious conditions while evaluating acute abdominal pain (Table 2). The location of pain should drive the evaluation, which has a strong predictive value in conditions such as appendicitis. A final diagnosis is not usually made at the first outpatient visit; therefore, it is critical to evaluate by ruling out serious disease (e.g. vascular diseases such as aortic dissection and mesenteric ischemia) and surgical conditions (e.g., appendicitis, cholecystitis). It also necessary to consider conditions of the abdominal wall, such as muscle strain or herpes zoster, because these are often misdiagnosed.¹Cartwright SL, Knudson MP. Evaluation of acute abdominal pain in adults. Am Fam Physician. 2008; 77(7):971-978.  

Physical Examination

Table 2: Differential diagnosis of abdominal pain¹Cartwright SL, Knudson MP. Evaluation of acute abdominal pain in adults. Am Fam Physician. 2008; 77(7):971-978.  

Inspection

The physical examination usually starts with general observation of the patient.⁴Murtagh J. Acute abdominal pain: A diagnostic approach. Aust Fam Physician 1994:23; 358-61.   A patient writhing in agony likely has colicky abdominal pain caused by ureteral lithiasis. On the other hand, a patient lying very still is more likely to have peritonitis, and a patient who is leaning forward to relieve the pain may have pancreatitis. The physician should examine the abdomen for surgical scars, trauma, distention, masses and hernia. Other parts of the body should also be inspected; eg: the eyes should be inspected for evidence of scleral icterus, which may indicate hepatobiliary disease.

Auscultation

Peristalsis can be assessed by auscultation of the abdomen. Bowel sounds are widely transmitted throughout the abdomen. Therefore, it is not necessary to listen in all 4 quadrants. The auscultation should however last for 1 minute. The diaphragm of the stethoscope should be used as the bowel sounds are high pitched. Bowel sounds are classified as normal, hyperactive or hypoactive. Hypoactive bowel sounds are associated with ileus, intestinal obstruction and peritonitis. Hyperactive bowel sounds are a result of intestinal obstruction. They are very audible. Auscultation should precede percussion and palpation.

Percussion

It is performed by firmly pressing the index finger of one hand on the abdominal wall, while striking the abdominal wall with the other index finger. Over the liver, percussion will produce a dull note. On the other hand, a hyper resonant note would be produced by percussion over the gastric region. Percussion can also be used to determine liver span. It is a useful method to determine the presence of ascitis or intestinal obstruction in a distended abdomen.

Palpation

The physician should avoid palpating the area that hurts the most in the patient, unless absolutely necessary. It may be difficult in guarding defined by spasms of the abdominal muscles.⁵Martin RF, Rossi RL. The acute abdomen. An overview and algorithms. Surg Clin North Am. 1997 Dec;77(6):1227-43.   Guarding can be voluntary or involuntary. Voluntary guarding occurs when there is conscious elimination of muscle spasms, and involuntary guarding is reported when the spasm response cannot be eliminated, which is suggestive of diffuse peritonitis.²Karnath B, Milenski W. Acute abdominal Pain. Hospital Physician 2002; 45-50.  

Diagnostic Testing

Laboratory tests:

The diagnostic tests vary depending on the clinical situation. A complete blood count is suitable in case of infection or blood loss. A study involving patients between 15 to 83 years of age with suspected appendicitis found that a white blood cell count greater than 10,000 per mm³ (10 × 10⁹ per L) was 77 percent sensitive and 63% specific for the diagnosis.⁶Kessler N, Cyteval C, Gallix B, et al. Appendicitis: evaluation of sensitivity, specificity,and predictive values of US, Doppler US, and laboratory findings. Radiology. 2004;230(2):472-478.  

Both amylase and lipase measurements are recommended in patients with epigastric pain. Liver chemistries are essential for right upper quadrant pain. A urinalysis is recommended in patients with haematuria, dysuria or flank pain. A urine pregnancy test is recommended in women of childbearing age. Testing for chlamydia and gonorrhoea is recommended for women at risk of sexually transmitted infections.¹Cartwright SL, Knudson MP. Evaluation of acute abdominal pain in adults. Am Fam Physician. 2008; 77(7):971-978.  

Imaging studies

The recommendations for initial imaging studies are dependent on the location of the abdominal pain (Table 3).

Table 3: Recommended imaging studies based on Location of abdominal pain¹Cartwright SL, Knudson MP. Evaluation of acute abdominal pain in adults. Am Fam Physician. 2008; 77(7):971-978.  

In patient with right upper quadrant pain, ultrasonography is recommended. For detecting acute cholecystitis, radionuclide imaging is slightly better than ultrasonography. However, it is more expensive, takes longer to perform and cannot assess diagnoses outside of the biliary tract.

Computed tomography (CT) with intravenous contrast media is the method of choice for evaluating adults with acute right lower quadrant pain. CT with oral and intravenous contrast media is the method of choice for evaluating adults with acute left lower quadrant pain.

The most common cause of left lower quadrant is sigmoid diverticulitis. CT has a reported sensitivity of 79 to 99% for detecting the condition. For diagnosing appendicitis, CT is better than ultrasonography. Left upper quadrant pain is caused by various clinical conditions and thus imaging recommendations are not clear. If the patient’s history and physical examination reveal oesophageal or gastric pathology, endoscopy (or an upper gastrointestinal series) is recommended. In patients with left upper quadrant pain, CT is useful because it provides imaging of the pancreas, spleen, kidneys, intestines and vasculature.

CT is highly effective technique to evaluate patients with nonspecific abdominal pain who need urgent intervention. Plain radiography of the abdomen can always be helpful as it is more readily obtainable and less expensive than ultrasonography or CT. A radiograph of the chest or abdomen can detect free air under the diaphragm, which is suggestive of perforation of the gastrointestinal tract. Abnormal calcifications also can be observed on a plain radiograph.

Women with child bearing age present a problem as it makes diagnostic decisions challenging. Gynaecologic causes of abdominal pain are more common in these women and radiation exposure should be avoided if pregnancy is likely. Therefore, in women of childbearing age and in pregnant patients with right lower quadrant abdominal pain, abdominal or transvaginal ultrasonography is the recommended method. In case of suspected ectopic pregnancy, transvaginal ultrasonography is recommended as it has a detection sensitivity of 95% in a patient with a positive pregnancy test and any abnormal ultrasound finding. In contrast, a negative pregnancy test and normal ultrasound findings virtually exclude ectopic pregnancy. Transvaginal ultrasonography can also be used to diagnose other gynaecologic conditions like fibroids, ovarian masses, ovarian torsions and tubo-ovarian abscesses.¹Cartwright SL, Knudson MP. Evaluation of acute abdominal pain in adults. Am Fam Physician. 2008; 77(7):971-978.  

Management

Management of acute abdominal pain requires:

• Rapid initial evaluation of pain intensity administration.
• Appropriate analgesic agent by the appropriate route based on the clinical scenario.
• Early implementation of adjuvant measures.

It is necessary to assess the intensity of the pain for proper management. The intensity of pain is a subjective perception, which does not correlate with clinical findings, laboratory parameters or diagnostic imaging findings. Various one-dimensional and multidimensional scales have been developed for objective assessment of individual pain (Figure 2). One-dimensional scales such as the visual analogue scale (VAS), Verbal Rating Scale (VRS) and numerical rating scale (NRS), as well as the ‘Smiley Analogue Scale’ (SAS) are used in the acute setting. Limitations for pain measurement include disturbances of consciousness, impaired vision and language barriers.

Figure 2: One-dimensional pain scales depicting examples of pain ratings. (A) Visual analogue scale (VAS). (B) Numerical rating scale (NRS). (C) Verbal rating scale (VRS). (D) The ‘Smiley’ analogue scale (SAS).

The route of administration of the analgesic agent should be determined relative to the estimated potential for enteric absorption of the delivered agent.⁷Falch C, Vicente D, Haberle H et al. Treatment of acute abdominal pain in the emergency room: a systematic review of the literature. Eur J Pain. 2014; 18(7):902-13.  

The various medications used for management of acute abdominal pain are:

Opioid analgesics

These are derived from opioid alkaloids. They bind to opioid receptors both in the central nervous system as well as in peripheral tissues to provide pain relief.

Weak opioids (e.g., Tramadol and Tilidine) are not considered adequate first-line agents in the treatment of acute abdominal pain. Pethidine (Meperidine), a weak opioid, was used in past for the treatment of acute biliary pain. However, it is no longer recommended due to the risk of accumulation of its active neurotoxic metabolite, Norpethidine and its relatively short duration of effect.

Piritramide, a potent intravenous opioid with a long duration of effect is used in the treatment of acute abdominal pain. It has demonstrated excellent results in post-operative analgesia. It should be administered in small doses and titrated to effect in order to keep side effects as low as possible.

Non-opioid analgesics

These non-opioid medications induce both central and peripheral analgesic effects by inhibiting cyclooxygenase and reducing prostaglandin (PG) synthesis.

These are divided into acidic and non-acid anti-pyretic analgesics. The main representatives of acidic anti-pyretic analgesics are non-steroidal anti-inflammatory drugs. The non-acidic antipyretic analgesics include pyrazolones [e.g., Dipyrone (Metamizole)] and anilines [e.g., Paracetamol (Acetaminophen)].

Paracetamol and Dipyrone can the two preferable non-opioid analgesics in patients with acute abdominal pain owing to their parenteral administration and rapid onset of action.

Antispasmodics

Amongst the various antispasmodics available, Drotaverine hydrochloride is a drug of choice in emergency abdominal pain of different aetiologies. It is a selective phosphodiesterase-IV (PDE4) inhibitor.⁸Rai RR, Dwivedi M, Kumar N. Efficacy and safety of drotaverine hydrochloride in irritable bowel syndrome: A randomized double-blind placebo-controlled study. Saudi J Gastroenterol. 2014;20: 378-82.   Since it does not mask the symptoms of the underlying disease it can be initiated for management of emergency abdominal pain even before the actual aetiological diagnosis is established.⁹Gupta K. Emerging role of Drotaverine in emergency medicine: A review. J Am Med Assoc Ind. Physicians’ Update. 1999; 2 (8): 57-64.  

Clinical evidence suggests that it is the drug of first choice in spasmodic pain of smooth muscle spasm like biliary colic, renal colic, intestinal colic, etc. Various post-marketing studies have shown that drotaverine is also effective in the treatment of pain associated with gastric and duodenal ulcer, gastritis, enteritis, cholelithiasis, colitis, cardiac and pyloric spasm and irritable bowel disease (IBS).¹⁰Blasko G. Pharmacology, mechanism of action and clinical significance of a convenient antispasmodic agent: Drotaverine. J Am Med Assoc Ind. Physician’s Update. 1998;1: 63-9.   Drotaverine also normalises the dysmotility of GI smooth muscles and displays significant improvement in stool frequency, consistency, urgency and flatulence in IBS.

Parenteral administration of drotaverine ensures rapid and immediate relief from spasmodic pain. Administered intravenously the action commences in just 2 minutes. The onset of action with the I.M. route is 5 minutes. Oral administration of Drotaverine can be continued for further sustaining its effects. Drotaverine is devoid of the anticholinergic side effects like constipation, dry mouth, blurred vision, tachycardia etc.⁹Gupta K. Emerging role of Drotaverine in emergency medicine: A review. J Am Med Assoc Ind. Physicians’ Update. 1999; 2 (8): 57-64.  

In the first of its kind paediatric study, Narang, et al. evaluated the efficacy of Drotavarine in cases of recurrent abdominal pain. A statistically significant reduction in the number of episodes of abdominal pain [mean (SD) number of episodes 10.3 (14) vs 21.6 (32.4); p=0.01] was observed in the Drotaverine group. Drotaverine also displayed statistically significant lesser school absence. The frequency of adverse events during follow-up period was comparable between children receiving Drotaverine or placebo (46.9% vs 46.7%; p=0.98).¹¹Narang M, Shah D, Akhtar H. Efficacy and Safety of Drotaverine Hydrochloride in Children with Recurrent Abdominal Pain: A Randomized Placebo Controlled Trial.Indian Pediatrics 2015; 52(10):847-51.  

In another study, the efficacy of Drotaverine was evaluated in 30 patients with cholelithiasis. It was observed that after i.v administration of Drotaverine, relief of spasm and pain occurred in 1-2 minutes. Studies have also shown that Drotaverine injection (both I.M. and I.V.) relieves pain in patients with clinically proven renal obstruction. It was also seen that the mode of administration did not influence the efficacy of the drug.⁹Gupta K. Emerging role of Drotaverine in emergency medicine: A review. J Am Med Assoc Ind. Physicians’ Update. 1999; 2 (8): 57-64.  

Romics et al. evaluated the spasmolytic effect of intravenous Drotaverine hydrochloride in colicky pain caused by renal and ureteric stones in a placebo controlled randomised trial. It was observed that Drotaverine was a more potent medicine with an effectiveness in 79% patients as compared with placebo which was effective in 46% (p<0.001).There were no serious adverse events observed in both the groups.¹²Romics I, Molnar D, Timberg G, et al. The effect of Drotaverine hydrochloride in acute colicky pain caused by renal and ureteric stones. BJU International. 2003;92(1):92-96.  

In another study involving 34 patients with nephrolithiatic attack, the colic ceased within 10-15 minutes. Total pain relief was experienced within 3-4 minutes of I.V. Drotaverine administration. Drotaverine was also effective in significantly reducing the discomfort caused by endoscopic intervention of the lower urinary tract. In a study involving 1824 patients, it was observed that 90% patients on Drotaverine found the endoscopi intervention less disagreeable.⁹Gupta K. Emerging role of Drotaverine in emergency medicine: A review. J Am Med Assoc Ind. Physicians’ Update. 1999; 2 (8): 57-64.  

Among all the antispasmodics available, Drotaverine is the safest as it can be safely administered in pregnancy, lactation, Benign Prostate Hyperplasia (BPH), elderly patients and patients suffering from Gastrointestinal Reflux Disease (GERD) and Glaucoma. It can also be safely co-administered with other drugs. In a study involving 4946 patients on drotaverine, 4740 patients reported no side effects.⁹Gupta K. Emerging role of Drotaverine in emergency medicine: A review. J Am Med Assoc Ind. Physicians’ Update. 1999; 2 (8): 57-64.  ¹⁰Blasko G. Pharmacology, mechanism of action and clinical significance of a convenient antispasmodic agent: Drotaverine. J Am Med Assoc Ind. Physician’s Update. 1998;1: 63-9.  

Thus, it is suggested that Drotaverine hydrochloride is an effective and safe pharmaceutical agent in the management of emergency abdominal pain from any origin.

Conclusion

Acute abdominal pain is a common cause for outpatient presentation and hospitalisation. It is necessary to take a meticulous history and perform a thorough physical examination to ascertain the exact cause. Choosing the correct laboratory and imaging studies is also essential. Management involves the use of opioid analgesics, non opioid analgesics and antispasmodics. Drotaverine hydrochloride has been found effective and safe in the management of emergency abdominal pain of any origin. Taking into consideration the clinical evidence, it can be concluded that Drotaverine is an effective and safe drug that results in rapid relief of pain and spasms without masking the signs and symptoms of the underlying disease.

References

1. Cartwright SL, Knudson MP. Evaluation of acute abdominal pain in adults. Am Fam Physician. 2008; 77(7):971-978.
2. Karnath B, Milenski W. Acute abdominal Pain. Hospital Physician 2002; 45-50.
3. Abdullah M, Firmansyah M. Diagnostic approach and management of acute abdominal pain. The Indonesian journal of Internal Medicine 2012; 44(4): 344-350.
4. Murtagh J. Acute abdominal pain: A diagnostic approach. Aust Fam Physician 1994:23; 358-61.
5. Martin RF, Rossi RL. The acute abdomen. An overview and algorithms. Surg Clin North Am. 1997 Dec;77(6):1227-43.
6. Kessler N, Cyteval C, Gallix B, et al. Appendicitis: evaluation of sensitivity, specificity,and predictive values of US, Doppler US, and laboratory findings. Radiology. 2004;230(2):472-478.
7. Falch C, Vicente D, Haberle H et al. Treatment of acute abdominal pain in the emergency room: a systematic review of the literature. Eur J Pain. 2014; 18(7):902-13.
8. Rai RR, Dwivedi M, Kumar N. Efficacy and safety of drotaverine hydrochloride in irritable bowel syndrome: A randomized double-blind placebo-controlled study. Saudi J Gastroenterol. 2014;20: 378-82.
9. Gupta K. Emerging role of Drotaverine in emergency medicine: A review. J Am Med Assoc Ind. Physicians’ Update. 1999; 2 (8): 57-64.
10. Blasko G. Pharmacology, mechanism of action and clinical significance of a convenient antispasmodic agent: Drotaverine. J Am Med Assoc Ind. Physician’s Update. 1998;1: 63-9.
11. Narang M, Shah D, Akhtar H. Efficacy and Safety of Drotaverine Hydrochloride in Children with Recurrent Abdominal Pain: A Randomized Placebo Controlled Trial.Indian Pediatrics 2015; 52(10):847-51.
12. Romics I, Molnar D, Timberg G, et al. The effect of Drotaverine hydrochloride in acute colicky pain caused by renal and ureteric stones. BJU International. 2003;92(1):92-96.