RIF Pain Flashcards
Mr Beck is a 28-year-old builder who presents at accident and emergency (A&E) on Sunday evening with a 3-hour history of right iliac fossa (RIF) pain. He is nauseated and has vomited once.
What is your differential diagnosis? Try to prioritize into those conditions that are most likely (or most common), those that you must exclude, and the remainder.
Appendicitis Gastroenteritis Ureteric colic Acute pancreatitis Testicular torsion Meckel’s diverticulitis Small bowel obstruction Caecal volvulus Perforated peptic ulcer Pyelonephritis Diabetic ketoacidosis Acute onset ileitis (bacterial or Crohn’s) Constipation Caecal diverticulitis Mesenteric adenitis Urinary tract infection Cholecystitis Shingles Rectus sheath haematoma
Describe how age can impact the diagnosis of RIF pain
Note that certain diagnoses are going to be more likely in different patient groups. Children and the elderly are more likely to have a longer differential as symptoms are often less pronounced and non-specific. Intussusception is almost exclusively seen in children, and the vast majority of cases of mesenteric adenitis are also seen in children. By contrast, caecal pathology (tumours, volvulus, or a solitary mesenteric diverticulum) is usually associated with advancing age.
What other diagnoses must you consider in a female patient?
You must of course consider gynaecological pathology, such as ectopic preg- nancy, pelvic inflammatory disease/salpingitis, torsion/haemorrhage/rupture of an ovarian tumour or cyst, mittelschmerz (mid-cycle pain corresponding to a ruptured ovarian follicle), threatened abortion, fibroid degeneration, or uterine dehiscence.
In any woman of reproductive age you must perform a pregnancy test – this is not only to exclude particular diagnoses such as ectopic pregnancy, but is also essential if you wish to proceed to tests such as abdominal radiographs which would risk harm to the foetus.
On further questioning we establish that Mr Beck had a milder, poorly localized, central abdominal pain for about 12 hours prior to the onset of the RIF pain. The pain worsened about 3 hours ago, at which time he felt that it had shifted to the right. The pain has been constant ever since. He says that the pain doesn’t radiate anywhere else, but struggles to give much more of a description when asked to characterize it – ‘pain is pain’. He hasn’t taken anything for the pain but states that he’d rate it as 8 out of 10. He is not aware of anything that makes the pain worse, but is reluctant to lie flat on the bed, and you notice that he keeps his right hip flexed. He had his customary Saturday night curry yesterday. He ordered the hottest dish on the menu, but says that he always does this and never suffers any ill- effects. None of his friends from the meal have had similar symptoms. He has completely lost his appe- tite today and has not opened his bowels either. He has felt otherwise well over the preceding week. Mr Beck’s face appears flushed and, as already noted, he is reluctant to lie flat.
With this history in mind, you need to examine Mr Beck to try and narrow your differential. In particular, you need to establish the site and extent of abdominal tenderness. How will you do this?
Note that tenderness is a sign whereas pain is a symptom.
It is very useful to have an idea of the degree of abdominal tenderness before you even lay a hand on the patient. Remember that you will win no prizes if you actually cause a patient pain. So, start by asking the patient to suck their tummy in as far as possible and then puff it out again (this is particularly useful in children). A patient with board-like abdominal rigidity secondary to generalized peritonism will only make very minor movements. Now ask the patient to cough – patients with inflam- mation of the parietal peritoneum will find this rather painful and may well place their hands over the area of tenderness.
Whether you palpate the abdomen in quadrants or nine zones, be sure to start in the opposite area to that which the patient states is most painful. Start by palpating gently and keep looking at the patient’s face for a reaction. Patients are likely to dem- onstrate guarding (involuntary muscular rigidity in tender areas of the abdomen). Percussion tenderness, when percussion over an area causes the patient pain, is a sensitive means of demonstrating parietal peritoneum irritation and is far kinder to the patient than assessing rebound tenderness.
What else will you be looking for on examination?
• Is he ill? As a first line you should establish whether Mr Beck is febrile and/or tachycardic, hypotensive, or tachypnoeic. Also quickly note any fetor oris (bad breath), which can indicate abdominal sepsis (such as appendicitis).
• Scars: scars in particular anatomical sites can be particularly informative – for example, has this patient still got an appendix? Remember that any previous abdominal surgery will also make small bowel obstruction more likely as post- surgical adhesions predispose to obstruction.
abdominal surgery will also make small bowel obstruction more likely as post- surgical adhesions predispose to obstruction.
• Abdominal distension or visible peristalsis: in a thin patient you may be able to observe these signs of small bowel obstruction.
• Cervical lymphadenopathy: particularly important for trying to rule out mesenteric adenitis, which is inflammation and enlargement of the mesen- teric lymph nodes. It often follows an upper respiratory tract viral infection (hence cervical lymphadenopathy may be present) and is one of the most dif- ficult conditions to differentiate from appendicitis in young patients.
• Masses: the greater omentum can wrap around inflamed organs, hence creat- ing a localized mass (such as an appendix mass). Other palpable masses may be due to a tumour or a rectus sheath haematoma. The history in Mr Beck’s case is rather short, but in someone with a longer history of constipation you may be able to palpate faecal loading in the sigmoid and colon.
• Bowel sounds: these will be absent if there is functional bowel obstruction (ileus) or perhaps ‘tinkling’ if there is small bowel obstruction.
• Hernias: a particularly important cause of small bowel obstruction.
• Rectal exam: provides three key pieces of information:
− Is the rectum full of faeces, thus suggesting constipation?
− Is there any blood? If so, think of pathologies such as a bleeding Meckel’s
diverticulum or caecal diverticulum.
− Is there any local tenderness? Remember that the appendix can lie in a
number of positions relative to the caecum. An inflamed pelvic appendix may not result in any abdominal tenderness to palpation, and the only sign may be right-sided rectal tenderness. However, the lack of rectal tender- ness does not rule out appendicitis.
• External genitalia: you must examine the testicles for signs of torsion – par- ticularly in young men. Torsion can present with referred pain to the abdomen via T10 sympathetic innervation. The window of opportunity for surgical rescue of torted testes is slim.
Mr Beck is febrile (37.8oC), tachycardic (102 bpm), and normotensive (134/78 mmHg) with a respiratory rate of 20/min. He has fetor oris. He’s asked to cough and finds this incredibly painful – clutching his hands over his right side. There is guarding in the RIF. In addition, palpation in the left iliac fossa results in greater pain in the RIF than the left (Rovsing’s sign positive). There are no palpable cervical lymph nodes and no abdominal masses. Owing to the tenderness of Mr Beck’s abdomen, it is difficult to palpate for the liver, spleen, and kidneys. Nevertheless, this is attempted and no organomegaly is detected. His abdominal aorta is pulsatile but not expansile. Percussion tenderness is maximal over a point approxi- mately two-thirds of the distance from the umbilicus laterally towards the anterior superior iliac spine (McBurney’s point). Bowel sounds are normal. Examination of the external genitalia and hernial orifices is unremarkable. Once it is explained why a digital rectal examination would aid diagnosis, Mr Beck con- sents to the procedure. The rectum is empty, there is no blood, and no focal tenderness.
Although Mr Beck’s history and examination are highly suggestive of a particular diagnosis, there are still a number of other contenders to rule out. What investigations would you like to request to refine your differential diagnosis?
- Full blood count (FBC): the white cell count may be elevated in response to any inflammatory condition (e.g. appendicitis, cholecystitis, or basal pneumonia).
- C-reactive protein (CRP)/erythrocyte sedimentation rate (ESR): elevated inflammatory markers point towards an inflammatory picture although, as with the white cell count, they are non-specific regarding the cause.
- Urea and electrolytes (U&Es): useful for establishing the baseline electrolyte status of the patient (remembering that a number of the diagnoses on our differ- ential will require intravenous (IV) fluids and/or surgery). Urea is also used as a prognostic indicator for pancreatitis as part of the modified Glasgow criteria.
- Serum amylase (or lipase) levels: high amylase (or lipase) levels are strongly suggestive of pancreatitis, although they are non-specific and thus must be viewed in the context of the clinical picture. Slight increases (200–600 U/L) in amylase levels are most commonly caused by pancreatitis, but also by various other pathologies such as bowel obstruction, mesenteric ischaemia, a pos- teriorly perforated duodenal ulcer, mumps, pancreatic carcinoma, or opiate medications. However, very high amylase levels (>1000 U/L) or elevated lipase levels (>300 U/L) are almost exclusively found in pancreatitis. (The exact cut- offs will depend upon your local laboratory protocols.) If you have any clinical suspicion of pancreatitis you should also request markers used in the modified Glasgow score for pancreatitis severity (FBC, calcium, urea, liver enzymes, lactate dehydrogenase (LDH), albumin, glucose, arterial blood gas).
- Glucose: remember that diabetic ketoacidosis can present with an acute abdo- men and that infection is likely to cause disturbed glycaemic control in diabet- ic patients. Glucose levels are also part of the Glasgow pancreatitis criteria.
- Liver enzymes: within the context of a raised amylase, these provide useful prognostic information for pancreatitis (which can result in elevated aspar- tate aminotransferase (AST) and low albumin). Liver enzymes are also essen- tial if there is any clinical suspicion of biliary pathology.
What urine tests would you perform
• Urinalysis: in the context of the acute abdomen, haematuria may result from infection, renal/ureteric calculi, or rarely an inflamed pelvic appendix that is irritating the bladder or retrocaecal appendix irritating the ureter. Glucose and ketones are indicative of diabetic ketoacidosis. A combination of leuco- cyte esterase and nitrites suggests a urinary tract infection. Both urinary tract infection and appendiceal irritation of the bladder can result in proteinuria but these could be distinguished by performing urine microscopy looking for bacteria, which would confirm the urinary tract infection.
What imaging would you perform
Imaging
• Abdominal radiograph: look for signs of a perforation (resulting in air in the peritoneal cavity), small bowel obstruction, or volvulus. Dilatation of a few ‘sentinel’ loops reflects a response to inflammation of other local structures such as the pancreas or appendix. Approximately 80% of renal/ureteric calculi are radio-opaque and thus visible on a plain abdominal radiograph. It may also be possible to see an appendiceal faecolith that is causing appendicitis.
• Abdominal ultrasound: this can be a very useful test if there is an atypical history such that renal or biliary pathology are likely differentials. Appendicitis can be sug- gested by ultrasound scanning. Ultrasound is also a useful test for detecting free fluid in the abdomen. Ultra sound may be particularly useful in female patients, where the differential diagnosis is broadened by gynaecological pathology.
Describe some other investigations to consider
Other investigations to consider are:
• Erect chest radiograph: request if there is any clinical suspicion of a perfo- rated viscus. Air under the diaphragm could result from a perforated peptic ulcer, Meckel’s diverticulum, caecal diverticulum, or appendix. Lung consoli- dation from a basal pneumonia would also be visible.
• Abdominal CT: CT scans involve a considerable dose of radiation, and the delay in requesting a scan may be unacceptable for some diagnoses such as acute appendicitis. However, CT is useful for pre-operative incision planning, aiding discussion of stomas, diagnosis of metastatic tumour deposits, etc.
• ECG: although this would be a very atypical presentation of myocardial inf- arction, one must be wary (particularly in elderly patients).
Blood tests are taken. The white cell count is 13.2 × 109 cells/L (neutrophils 10.5 × 109 cells/L), CRP 32 mg/L, and amylase 200 U/L. All other blood tests are unremarkable. Urine dipstick is negative for protein, blood, leucocyte esterase, nitrites, glucose, and ketones. A plain abdominal radiograph shows a single dilated loop of small bowel in the RIF, but nothing else of note. There are no signs of pneumoperitoneum.
In light of the history, examination and first-line investigations, what is the most likely diagnosis?
This is a classical clinical picture for acute appendicitis: low-grade central abdom- inal pain that gradually migrates to the RIF over 12–24 hours and becomes more intense. Anorexia is a reliable feature. The patient is flushed, febrile, tachycardic, has foetor oris, and is lying still. Examination reveals guarding and percussion tender- ness in the RIF – perhaps over McBurney’s point. Digital rectal examination may also show right-sided tenderness. Rovsing’s sign may be positive but is an unreli- able sign. Bear in mind that this classical presentation is only seen in about 50% of patients. The appendix can lie in various positions relative to the caecum and thus produces various different examination findings when inflamed. Furthermore, there is no single test that is diagnostic for appendicitis.
What features of the history, clinical examination, and investigations help you rule out other diagnoses?
We can go through the differential diagnosis given initially and try to rule out alternatives to appendicitis:
• Mesenteric adenitis? Typically follows an upper respiratory tract infection or sore throat, thus cervical lymphadenopathy may be present. It is most com- mon in children less than 15 years old. In truth, it is very difficult to distinguish between appendicitis and mesenteric adenitis, with the final diagnosis being made intraoperatively in many cases. The pain with mesenteric adenitis is often more diffuse than that of appendicitis, and signs of peritonitis are often absent. Mesenteric adenitis doesn’t result in rectal tenderness, but appendici- tis doesn’t always result in this sign either. Fever is said to be slightly higher in mesenteric adenitis (>38.5oC), but this too is unreliable. Mesenteric adenitis often settles quickly.
- Meckel’s diverticulitis? As with mesenteric adenitis, it is almost impos- sible to definitively exclude an inflamed/ruptured Meckel’s diverticulum pre-operatively. Signs and symptoms are classically indistinguishable from appendicitis.
- Constipation? This would not cause a migration of pain to the RIF. We would also expect to feel faeces in the rectum and see faecal loading of the colon on plain abdominal radiographs. Constipation virtually never results in fever or tachycardia.
- Acute onset Crohn’s disease? Although the acute signs and symptoms would mimic appendicitis, there is often a history of diarrhoea and weight loss for weeks/months leading up to the acute presentation.
- Gastroenteritis? Vomiting and diarrhoea would usually predominate. The shifting nature of pain, and localized abdominal tenderness are not typical. In addition, you may expect to see similar symptoms in other family members or close contacts.
- Renal/ureteric colic? The patient would typically be writhing in pain (rather than lying still). Pain would not migrate from the central abdomen. Urine dip- stick would likely show haematuria, and plain abdominal radiograph would show a stone or stones in about 80% of cases.
- Pancreatitis? The migration of the pain to the RIF would be atypical for pan- creatitis. Furthermore, if there is RIF pain we’d also expect there to be epi- gastric pain. Although the serum amylase is very slightly raised, it is not high enough to raise suspicions of pancreatitis (typically >1000 U/L, but levels may be normal even in severe pancreatitis). It is worth remembering that other intestinal pathology such as appendicitis, intestinal infarction, and perforated duodenal ulcer can also cause raised amylase levels, as can head injury, dia- betic ketoacidosis, and drugs such as opioids. If Mr Beck did have pancreatitis it would be a very mild version as his Glasgow score is zero (see Chapter 12).
- Testicular torsion: there are no signs of testicular tenderness (see Chapter 25).
How will the surgical team manage Mr Beck?
The first step is to assess the need for resuscitation (Airway, Breathing, and Circulation, ABC). IV fluids would be given if required. He would then be given adequate analgesia. The first-line treatment for appendicitis is appendicectomy, either open or laparoscopic. Patients should be nil by mouth for 6–8 hours prior to surgery, although most appendicitis patients have usually lost their appetite anyway. Intraoperative mortality in the UK is <0.2%, but rises to about 5% in the very young or elderly as the difficulty of diagnosis in these patient groups means that they are more likely to present with perforation. Peri-operative broad-spectrum antibiotics should be used in all appendicectomies as they reduce wound infection and abscess formation. The patient should also be prescribed some form of deep vein thrombo- sis (DVT) prophylaxis.
Mr Briggs is a 46-year-old solicitor admitted to the surgical unit at the same time as Mr Beck. He describes a similar history of central abdominal pain that migrated to the RIF. However, he has waited 3 days before seeking help. He has been taking paracetamol 1 g q.d.s. (four times a day) at home, but this has not controlled his pain. He has not eaten a proper meal for 3 days, and has only passed minimal amounts of stool. On examination, he is flushed, tachycardic, and febrile. There is marked halitosis. There is muscular rigidity in the RIF, and a tender mass is palpable in the RIF. The rest of the abdomen is soft and non- tender. Per rectum, genital, and hernial orifice examinations are all unremarkable.
What has happened to Mr Briggs?
It is likely that Mr Briggs has also had acute appendicitis but that he has suffered a complication and has now developed an appendix mass. The greater omentum, caecum, and/or adherent loops of small bowel wrap themselves around the inflamed or perforated appendix to form a localized mass. CT or ultrasound scan may clinch the diagnosis. The fact that Mr Briggs has waited 3 days before presenting to hos- pital does not necessarily mean that he is any more stoical or able to tolerate more pain than our previous patient. Rather patients who develop an appendix mass are usually those who have had a less intense pain resulting from ‘milder’ inflammation of the appendix.
Initial conservative therapy is usually indicated for an appendix mass. This involves keeping patients nil by mouth, ensuring adequate IV fluids, antibiotic cover, analgesia, and DVT prophylaxis, and then marking out the size of the mass on the abdominal wall. Surgery is indicated if the mass increases in size, if the patient becomes more septic, or if the patient develops small bowel obstruction due to the adhesions.
If early surgery is not indicated and the mass resolves with conservative treat- ment, it is usual to perform an elective appendicectomy 6–8 weeks after resolution of the mass, although elective removal of the appendix following resolution of the mass remains controversial.
It is worth emphasizing the difference between an appendix mass and appendix abscess. The former is a phlegmon (an inflammatory mass) whereas an abscess con- tains pus. Hence a conservative approach can be adopted for an appendix mass but an abscess must be drained – either as an open procedure or percutaneously.
Mr Fuhr is a 16-year-old student who presents to the surgical emergency unit with a 3-hour history of RIF pain. He has vomited once. He was specifically asked whether he had any central abdominal pain prior to the RIF pain but he is unsure. He was playing rugby earlier in the day and, as he doesn’t like to play with a full stomach, says that it is usual for him to have some rumbling stomach pains prior to a big match. He has otherwise been fit and well. On examination, his temperature is 37.4oC and pulse is 134 bpm, regular. His is in obvious discomfort. However, abdominal examination is unremarkable – there are no local areas of tenderness; no palpable masses; bowel sounds are present. Urine dipstick is negative. Bloods are sent for analysis.
Which critical examination has not yet been performed? Which diagnosis must we consider?
Mr Fuhr is exactly the right sort of age to present with testicular torsion. It is absolutely critical that all boys/young men have their testes examined when present- ing with an acute abdomen. A thorough gastrointestinal examination of patients of any age should feature inspection of external genitalia and hernial orifices, and a digital rectal examination if appropriate.
Signs of testicular torsion include an exquisitely tender testicle and scrotal ery- thema. The abdominal pain is referred via the T10 sympathetic supply and reflects the embryological origin of the testes. Nausea and vomiting are commonplace. The affected testis will lie higher in the scrotum than a normal testis. A testis that lies horizontally is more likely to tort, so examine the other testis as well. Prehn’s sign is said to help distinguish between epididymitis and testicular torsion: elevating the affected scrotum relieves the pain of epididymitis (positive Prehn’s), but will not relieve the pain of torsion. However, although you may hear Prehn’s sign being men- tioned on the wards, it is not a reliable sign. More information would be gleaned by attempting to elicit the cremasteric reflex (downwards stroking of the supero- medial aspect of the thigh should result in elevation of the ipsilateral scrotum/testi- cle). Although the absence of the cremasteric reflex does not diagnose torsion (as it is very frequently absent), it has a negative predictive value of 96% – in other words, its presence is strongly suggestive of another pathology.
Although the majority of testicular torsions appear to happen spontaneously (often at night), they may follow minor trauma. Doppler ultrasound of the testes may aid diagnosis, but if there is any suspicion of torsion it is safest to send the patient to theatre as time really does matter (90% chance of rescuing testis at 6 hours, 5% at 24 hours). If there is a delay in reaching theatre it may be appropriate to attempt manual de-rotation of the testis. It is important to warn patients and parents prior to theatre that both testicles will need fixing to avoid future torsions, and that the affected testicle may need to be removed if it appears necrotic.
Miss Bakewell is a 12-year-old girl who presents to her GP with RIF pain. It is difficult to establish much of a pain history, but it seems as though she has had this pain for about a day. The GP notes that one of his colleagues saw Miss Bakewell last week and diagnosed a suspected viral pharyngitis. Upon examination today there is moderate peri-umbilical and RIF tenderness to light palpation, but no guarding or rebound. The GP decides that it would not be appropriate to perform a digital rectal examination. He does, howev- er, ask her for a urine sample. With her consent he then performs a pregnancy test and this is negative. In addition there are no signs of urinary tract infection on urine dipstick testing. Miss Bakewell has a fever of 38.6oC and pulse 121 bpm, regular. The rest of the examination is unremarkable, except for a palpable right-sided submandibular lymph node. The GP decides to refer Miss Bakewell to the local hospital. He rings the admissions unit to warn of her arrival.
What is he likely to mention as the differential diagnoses?
Given that we can rule out ectopic pregnancy or threatened miscarriage, our most likely diagnoses would be appendicitis or mesenteric adenitis. The slight- ly higher fever, lack of guarding, and history of upper respiratory tract infection perhaps swing the pendulum in favour of mesenteric adenitis, but Miss Bakewell will need admitting for observation in case this is appendicitis. Miss Bakewell may proceed to surgery (laparoscopy) if her condition worsens enough to warrant it (so that appendicitis can be ruled out). It is, however, rare to need surgery in cases of mesenteric adenitis.
