Transcript Right iliac fossa pain – modality directed diagnostic approach

Right iliac fossa pain – modality
directed diagnostic approach
John-Henry Corbett
Diagnostic Radiology
University of the Free State
03/2012
• Acute right iliac fossa pain is a common clinical
emergency
• Requires prompt investigation and diagnosis to
limit morbidity and mortality
• Physical and laboratory findings are often nonspecific
• Clinical presentations of potential causes overlap
• Diagnostic imaging is used increasingly at an
earlier time to aid in diagnosis
• Acute appendicitis is the most common condition
• In up to one third the cause is not apparent
More common in adults
More common Adult females
in the elderly
Genitourinary
Medical
Appendicitis,
Appendix
abscess
Inflammatory
bowel disease
Caecal tumour
Ruptured ectopic
pregnancy
Ureteric calculus
Pneumonia
Gastroenteritis
Epiploic
appendagitis
Caecal
perforation
Adnexal torsion
Urinary tract
infection
Diabetic
ketoacidosis
Intestinal
obstruction
Acute
cholecystitis/
ascending
cholangitis
Acute
diverticulitis
Ruptured/
torsion
ovarian cyst
Pyelonephritis
Nerve root
entrapment
Pancreatitis,
Peptic ulcer
perforation
Inguinal or
femoral
hernia
Caecal or
sigmoid
volvulus
Pelvic
inflammatory
disease
Testicular torsion
Herpes zoster
Carcinoid
Ischaemic bowel
Abdominal aortic
aneurysm
Endometriosis
Constipation
Ruptured
ovarian
follicle
Lymphoma
Acute porphyria
Selection of the most appropriate
imaging modality
• Depends on
– 1) Patient age and body habitus
• < 20 years
– Ultrasound initially, regardless of suspected pathology
– Then CT or MRI if additional information is required
• > 20 years
– Ultrasound initially in young, slim adults
» Particularly women of reproductive age
• Older or obese patients
– CT
Selection of the most appropriate
imaging modality
• Depends on
– 2) Suspected pathology, based on clinical and
laboratory findings
•
•
•
•
•
•
Appendicitis
Renal colic
Gynaecological
Hernia
Bowel related
Vascular
Acute appendicitis
• Most common cause of acute RIF pain
• Clinical diagnosis on patient history and physical
examination
– Any age, but most common 10-20 years
– Abdominal pain
• Colicky, central abdominal pain
• Followed by vomiting and migration of pain to RIF (50%)
– Loss of appetite, constipation, nausea
– Pyrexia, tachycardia and localized tenderness
– Accuracy for clinical diagnosis
• Men : 80-90%
Women : 60-80%
Alvarado score
• 0-4 could be discharged without
imaging
•scores of 4-6 undergo imaging
evaluation
•scores of 7 or above receive surgical
consultation
Acute appendicitis
• Conventional surgical wisdom is based on the
belief that an inverse relationship exists between
the negative appendectomy rate (NAR), i.e.
removal of a non-inflamed appendix, and the
perforation rate
• Thus, a false-negative appendectomy rate of 15–
23% is regarded as an index of appropriate
management and the failure to maintain such a
surgical threshold is an indication of insufficient
surgical aggression, with an attendant risk of an
excessive rate of perforation
Acute appendicitis
• Ultrasound
– Advantages
• Widely available and inexpensive
• Avoidance of ionizing radiation
– Especially women of reproductive age and children
– Gynecological disease gives further reason for U/S evaluation
• Usefull in identifying an alternative diagnosis
– Disadvantages
• Operator dependant
– Technique
• Graded compression with high frequency linear probe
– gradual and constant increase in the compression by the US
probe in the right iliac fossa
– displaces normal, air-filled bowel, or compresses it against the
posterior abdominal wall
– abnormal, non-compressible appendix is thus revealed
Acute appendicitis
• Ultrasound
– Technique
• Aperistaltic, blind ending tubular structure
• Arises from the base of the cecum
• Key diagnostic features of inflammation
– Non-compressible appendix with diameter >6mm
– Supporting findings
» Presence of appendicolith
» Circumferential color Doppler signal (inflammation)
» Inflammatory changes in the perienteric fat
• Echogenic mass
• Normal appendix infrequently seen – up to 4%
– Retrocaecal and pelvic appendices are more difficult to visualize
• Perforation of the appendix causes it to decompress and the signs
of non-compressibility and distension are lost
– Identification then relies on secondary features such as abscess
formation
– Specificity of 60%
Transverse U/S : Inflammed
appendix (between calipers) ;
adjacent inflamed fat (arrow) ;
terminal ileum with air (curved
arrow)
Longitudinal U/S : inflammed
appendix with proximal
appendicolith
Acute appendicitis
• CT
– Technique
• Variety of techniques in an attempt to
– Reduce radiation dose
– Maximize diagnostic yield
– Minimize preparation time for the scan
• Variation in
– Amount of abdomen imaged
– Use of IV, oral and rectal contrast
• All share same basic concept
– Acquiring thin collimation images (5mm or less) in a single breath
hold
• Unenhanced CT abdomen (No IVI, oral or rectal contrast)
– Reduces delay for patient preparation and reduces per patient cost
– Relies on intra-abdominal fat to provide contrast
» Difficult to obtain good results in thin patients
– More difficult to interpret initially, but just as accurate when
experienced
Acute appendicitis
• CT
– Appearance on CT
• Filling of appendix with oral contrast is an important negative feature
• Normal appendix wall 1-2mm in thickness
• Periappendiceal fat should appear homogenous
– CT diagnosis of acute appendicitis can be made if
• Abnormal appendix identified
–
–
–
–
Appendix diameter > 6mm
With homogenously enhancing wall
Mural edema may produce a target sign
Periappendiceal inflammation in 98%
» Fat stranding
• Calcified appendicolith with pericecal inflammation
– Perforated appendicitis
• Accompanied by pericecal phlegmon or abscess
• Associated findings
–
–
–
–
–
Extraluminal air
Ileocecal thickening
Localized lymphadenopathy
Peritoneal enhancement
Small bowel obstruction
Inflamed appendix with a target
sign : enhancing serosa and mucosa
Appendix abscess : Ring enhancing
collection with adjacent appendicolith
seperated by oedematous fluid in wall
Appendicitis : dilated
appendix ; appendicoliths ;
adjacent fat stranding
Acute appendicitis
• MRI
– Currently limited to patients with
right iliac fossa pain during pregnancy
• Avoiding ionizing radiation is of prime
importance
– Limited information available
• small number of studies with little
patient numbers
– Imaging techniques used
• no IV contrast
• axial, coronal and sagittal noncontiguous T2-weighted single-shot fast
spin-echo (SE) sequences
• axial fat-suppressed T2-weighted fast SE sequences
• axial T1-weighted gradient-recalled-echo sequences
• axial and coronal inversion-recovery sequences performed through
the lower abdomen and pelvis
– Illustrates normal and abnormal appendix
• May be useful in diagnosing adnexal pathology
Appendicitis : dilated appendix (black
arrowhead) ; appendicolith (black arrow) ;
adjacent fat stranding (white arrowheads)
Crohn’s disease
• Although inflammatory bowel disease is usually a
chronic condition, flare-ups may present acutely
• Peak age of onset 15-30 years
• Many cases of Crohn’s diagnosed during work-up of
acute LRQP since ileocecal region is most commonly
affected
– Apposed to ulcerative colitis which dominates the left colon
• CT best imaging modality
– Two most common imaging findings
• Eccentric wall thickening
• Mucosal hyperenhancement
Crohn’s disease
• CT imaging
– Presence of intramural fat indicates chronic changes
– Segmental involvement with skipped (normal) regions
• vs ulcerative colitis – involves bowel in more continuous fashion
– Comb sign
• Engorgement of the vasa recta penetrating the bowel wall
• Advanced, extensive and active Chron’s disease
– Creeping fat sign
• Fibrofatty proliferation along the mesenteric border of the
affected bowel - almost pathagnomonic
– Complications
• Small bowel strictures causing obstruction
• Fistulas and abscesses
Crohn’s disease : Thickened terminal
ileum ; diagnosis confirmed at histology
Thickened terminal ileum ; strictures ;
mucosal hyperenhancement ;
proliferation of mesenteric fat (black
arrow)
Y shaped fistula : Cecum
(arrowhead) ; terminal ileum (white
arrow) ; psoas abscess (*)
Infectious enterocolitis
• Infectious enterocolitis have symptoms similar to viral
gastroenteritis
• Most cases require no imaging
– In cases of severe or persistent imaging is helpful for
differentiation from alternative diagnosis
• Most common organisms
– Yersinia enterocolitica
– Campylobacter jejeni
– Salmonella enteritidis
• Non-specific CT findings
– Circumferencial mural thickening
of terminal ileum and cecum
– Homogenous mural enhancement
– Adjacent lymphadenopathy
Neutropenic colitis (Typhlitis)
• Neutropenic patient undergoing chemotherapy
• RLQP, fever, diarrhoea, ± peritonitis
• CT is study of choice if suspected
– Risk of bowel perforation with contrast enema or
colonoscopy
• Typhlitis usually involves the right colon, but
terminal ileum and transverse colon may be
involved
• CT findings
– Cecal distension
– Circumferential wall thickening with areas of low
attenuation due to edema or necrosis
– Inflammatory stranding of adjacent mesenteric fat, ±
lymphadenopathy
Neutropenic colitis (Typhlitis) : cecal mural
thickening (white arrow) ; normal left colon wall (black arrow) ;
pericecal lymphadenopathy (arrowhead)
Diverticulitis
• One of the most common causes of acute
abdominal pain in the elderly
• Left and sigmoid colon predominantly affected
• Less commonly right colon and cecum may be
affected – mimicking appendicitis
• CT investigation of choice
– Asymmetric or circumferential colonic wall thickening
– Associated focal pericolic fat stranding
– Inflammed diverticulum often visible at level of
maximal fat stranding
– Normal appendix is important in differentiating from
appendicitis
– Pericolic lymphnodes suggests malignancy rather than
diverticulitis
Diverticulitis
• Rare causes
– Aquired small bowel diverticula
• Mucosal herniation of bowel at sites of vscular entry
• Mesenteric border of terminal ileum < 7,5 cm from
ileocecal valve
– Meckel diverticulum
• Most common congenital abnormality of the GI tract
• Omphalomesenteric duct does not obliterate during
development
• Anti-mesenteric border of ileum, ± 100 cm from
ileocecal valve
• May contain ectopic gastric mucosa
– Mucosal ulceration and GIT bleeding
Diverticulitis : Multiple right
colonic diverticula ; adjacent fat
stranding (arrow) ; sigmoid diverticula
with no fat stranding (arrowheads)
Diverticulitis : Multiple sigmoid diverticula
(straight white arrows) ; thick walled sigmoid colon
(curved white arrow) ;
arrow)
mesenteric fat stranding (black
Epiploic appendagitis
• Round fat containing peritoneal pouches
arising from serosal surface of the colon
– 0,5 – 5 cm in lentgh
– More common in left and sigmoid colon
• Uncommon and self limiting condition
• Mostly middle aged men
• Caused by torsion or
venous thrombosis of
the epiploic appendages
• CT findings
– Pericolic, round tot oval lesion
of fat attenuation with a
hyperattenuating rim
Mesenteric adenitis
• Primary mesenteric adenitis defined as
– Clustered (>3) right sided lymphnodes in small
bowel mesentery or anterior to psoas muscle
– Larger than 5mm
– No identifiable acute inflammatory condition
• More common in children
– Acute RLQP, fever, leukocytosis
• Diagnosis of exclusion
Malignancies
• LRQP may be the intial presentation of
malignancy involving the ileocecal region
• Especially in event of complications
like perforation or abscess
• Adenocarcinoma
– >95% of all malignant cecal masses
– Focal concentric mass with overhanging
shoulders
– Associated enlarged pericolic nodes
• Lymphoma
– 80% of lymphoma of ileum and colon occur in ileocecal
region
• Peyer patches (lymphoid tissue) develop in terminal ileum
– Older patients 50-70 yrs
Malignancies
• Lymphoma
– Non-specific symptoms (weight
loss and abd pain), so often
presents late
– Four forms of ileocecal lymphoma
• Circumferential or constrictive
– Most common and may mimic
adenocarcinoma
– Usually longer segment affected
more gradual transition from
tumor to normal bowel
– Lack of bowel obstruction in
presence of a large massshould
raise suspicion of lymphoma
• Polypoid
• Ulcerative
• Aneurysmal
Intussusception
• Rare in adults (<5%)
– Mostly idiopathic in children ; <2yrs (40% 3-6mnths)
– Adults secondary to lead point – benign or malignant neoplasm
• Target shaped bowel-within-bowel appearance is the
classic appearance on axial scans and is pathognomonic
Cecal volvulus
• Rare condition in patients with abnormally mobile
cecum
– Due to congenital or acquired abnormal fixation to the
posterior parietal peritoneum
• Predisposing or triggering factors
– Previous laparotomy, distal
obstruction, neoplasm, constipation
and pregnancy
• Presents with acute constant or cramping RLQP
• Three types
– type I : Axial torsion type
• the cecum twists in the axial plane, rotating along its long axis
– type II : Loop type
• the distended cecum twists and inverts
– type III : Cecal bascule
• the distended cecum folds anteriorly without any torsion
Cecal volvulus
• Diagnosis on plain radiography < 50% of cases
• MDCT can recognize subtypes and
complications (ischemia and obstruction)
– combination of a distended ectopic cecum and
the swirl of the mesenteric vessels is seen in type
I and II
– type II volvulus (the loop type), the cecum usually
occupies the left upper quadrant
– in the bascule type, the swirl of the vessels is not
present
Adult (reproductive age) females
• Ruptured ectopic pregnancy
– Ultrasound usually used to confirm intra-uterine
pregnancy and exclude ectopic pregnancy
– Identification of extrauterine gestational sac is
uncommon
– Ultrasound findings
• Empty uterus,(+ β-hCG), adnexal mass
• Complex fluid in the Pouch of Douglas is the only positive
finding in up to ¼ of patients
Ectopic pregnancy : Complicated adnexal
mass (arrow) in a 25-yearold woman with a
positive pregnancy test ; adjacent uterus (curved
arrowhead) did not contain a gestational sac
Adult (reproductive age) females
• Adnexal torsion
– Complete or partial rotation of
the adnexa along the vascular pedicle
• Predisposing factors in half of pt
– Ipsilateral functional cyst or neoplasm
– Ultrasound findings
• Incomplete torsion
– Massive ovarian edema
– Enlarged ovary with multiple peripheral
fluid filled spaces
• Complete torsion
– Similar picture, but complex cystic regions
due to ischemic necrosis
– Fluid in the Pouch of Douglas
Adult (reproductive age) females
• Ovarian cysts
– May cause pain by
• Predisposing to ovarian torsion
• Intra cystic hemorrhage
• Rupture
• Pelvic inflammatory disease
– Ascending spread of infection from the female genital
tract- Chlamydia trachomatis, Neisseria gonorrhoeae
– Inflammatory change of the fallopian tube is the
hallmark of PID
• Normally fallopian tubes are not seen on U/S
• If infection spread to ovary a tubo-ovarian complex forms
Pelvic Inflammatory
Disease : Occluded tube
(thick arrow) ; purulent
fluid (thin arrow)
peritoneal
Adult (reproductive age) females
• Endometriosis
– Most common cause of chronic pelvic pain
• May occasionally present acutely
– Endometrial tissue present outside the uterus
• Pouch of Douglas, ovaries, pelvic peritoneum
• GIT
– Rectosigmoid colon
– Ileum, jejunum and cecum
– Appendix <1%
– Transvaginal U/S of value in acute setting if suspected
– MRI of pelvis in more elective situation
• Endometriomas high signal on T1 and heterogenous
high T2
• Fat-Sat increases sensitivity
• Lesions > 1cm routinely seen
Adult (reproductive age) females
• Ruptured ovarian follicle
– During mid cycle rupture may realease small
amount of blood
– Resultant peritoneal irritation may cause transient
pain – mittelschmertz
Food for thought
•
•
•
Diagnostic laparoscopy in the evaluation of right lower abdominal pain: a one-year audit.
Authors : Lim GH, Shabbir A, So JB Institution Department of Surgery, National University Hospital,Singapore.
Source : Singapore Med J 2008 Jun; 49(6) :451-3.Abstract
•
INTRODUCTION
Acute appendicitis is the commonest cause for right lower abdominal pain. Clinical features, laboratory and
imaging investigations are either not very sensitive or specific, and neither is therapeutic. We aimed to define
the role of diagnostic laparoscopy in patients with right lower abdominal pain.
METHODS
Data was collected retrospectively from January 1, 2005 to December 31, 2005. Patients admitted to the
Emergency Department and subsequently transferred to the Department of Surgery, National University
Hospital, Singapore, with right lower abdominal pain and who eventually underwent diagnostic laparoscopy
were evaluated.
RESULTS
691 patients with right lower abdominal pain were admitted with suspected diagnosis of appendicitis.
Diagnostic laparoscopy was undertaken in 103 patients aged 17-71 years old. Of the 83 females, 78 (94
percent) were premenopausal . Histology-proven acute appendicitis was diagnosed in 78 (75.7 percent)
patients. Interestingly, within this group, 25.6 percent had other concomitant pathologies found on
laparoscopy. 25 patients had a normal appendix; gynaecological causes accounted for pain in 15 of these 25
(60 percent) cases. In four (3.9 percent) patients, no pathology was found. Complication rate was 1.9 percent,
which included ileus in two patients. In 32 (31.1 percent) patients, diagnostic laparoscopy altered the
management plan, requiring either intervention or care by a subspecialty.
CONCLUSION
Diagnostic laparoscopy is useful in evaluating patients with right lower abdominal pain, especially in those
with equivocal signs of acute appendicitis. It also has the additional benefit of being therapeutic.
Premenopausal women benefit the most from this procedure.
Food for thought
• Right iliac fossa pain in women. Conventional diagnostic approach versus
primary laparoscopy. A controlled study (65 cases)
Authors Champault G, Rizk N, Lauroy J, et al.
• Institution Service de Chirurgie Générale et Digestive, Hôpital JeanVerdier, Bondy.
Source Ann Chir 1993; 47(4) :316-9. Abstract
In a series of 187 patients with acute abdominal pain syndrome, 65
young women reported non specific pain in right iliac or pelvic area. A
controlled study compared 33 patients with immediate laparoscopy and
32 explored with a laboratory contrast or imaging approach. In the
laparoscopic group, an exact diagnosis was made in 97% of the patients,
allowing in 2/3 of cases the endoscopic treatment. Only 28% in the
second group had an exact diagnosis. Hospital stay was shorter in the
laparoscopic group (4.18 vs 6.16 days; p = 0.01) decreasing the hospital
cost. The authors suggest that immediate laparoscopy should be
performed in young women presenting with non-specific abdominal pain.
References
• Hoeffel C, Crema MD, Belkacem A et al. Multi-detector row CT: spectrum
of diseases involving the ileocecal area. RadioGraphics 2006; 26: 13731390.
• Pedrosa I, Zeikus EA, Levine D & Rofsky NM. MR imaging of acute right
lower quadrant pain in pregnant and nonpregnant patients. RadioGraphics
2007; 27: 721-753.
• Purysko AS, Remer EM, Leao Filho HM et al. Beyond appendicitis: common
and uncommon gastrointestinal causes of right lower quadrant abdominal
pain at multidetector CT. RadioGraphics 2011; 31: 927-947.
• Anderson EM & Bungay HK. Imaging investigation of acute right iliac fossa
pain. Imaging 2006; 18: 257-267.
• Department of Health Western Australia. Diagnostic imaging pathways:
acute right iliac fossa pain on www.imagingpathways.health.wa.gov.au
(last accessed on 07/03/2012).