Lecture 9- Abd US/CT Imaging Flashcards
1
Q
blunt vs penetrating trauma
A
- blunt: MVC, falls (tend to be multi-system and have higher risk mortality than penetrating)
- penetrating: gunshot, stabbing
2
Q
roadblocks to good history
A
- EtOH
- severe trauma
- substance abuse
- developmental delay
- psychiatric illness
- overlapping pain symptoms
3
Q
most common abd imaging modalities
A
US/CT
4
Q
describe FAST exam
A
- US done bedside by ED or trauma provider
- used as initial screening to evaluate for solid organ injury and intra-abd bleeding
- poorly evaluates hollow viscus injury
- does not exclude injury in blunt/penetrating traumas if negative
5
Q
6 places to do FAST exam
A
- R & L anterior chest
- RUQ/LUQ
- sub-xiphoid
- suprapubic
6
Q
CT scan types
A
- Non contrasted: do if contrast allergy, stone, renal insufficiency
- IV contrast: study of choice, identify devascularized areas, hematomas, active extravasation of blood, extraluminal urine
- rectal, oral
7
Q
Sx of contrast dye
A
- most common sx: itching, warmth, n/v, site irritation, hives, laryngeal irritation
- Acute tubular necrosis (24-48hrs post injection, fluids to mitigate risk, anuric ESRD ok for contrast)
- can premedicate w/ 40mg Solumedrol + 50mg Benadryl
8
Q
contrast complication- extravasation
A
- toxic to tissues (compartment syndrome, necrosis, ulceration)
- treat like burn, may require rad and surgical consult
- elevate + cold compress
9
Q
considerations for contrast dye w/:
* metformin use
* pregnancy
* breastfeeding
A
- metform: hold for 48hrs post CT due to risk of lactic acidosis/renal or liver failure
- pregnancy: crosses placenta, limited data on harm; if emergent do it, if non-emergent US preferred
- breast feeding: < 0.01% absorbed into milk, can pump & dump for 1d if concerned
10
Q
describe mild allergic rxn
A
- typical: limited urticaria, itchy/scratchy throat, nasal congestion, sneezing, rhinorrhea, conjunctivitis
- additional: mild HTN, HA, dizziness, anxiety, altered taste, flushing/warmth
- typically is limited/transient
- vasovagal rxn which resolves spontaneously
11
Q
describe moderate contrast rxns
A
- typical: diffuse urticaria/prutitis, erythema w/ stable vitals, facial edema w/out dyspnea, throat thightness or hoarseness, wheezing
- additional: protracted n/v, hypertensive urgency, isolated CP
- requires tx to fix
12
Q
describe severe contrast rxns
A
- typical sx: diffuse edema, dyspnea, erythema w/ hypotension, laryngeal edema w/ stridor, hypoxia, wheezing, bronchospasm, anaphylactic shock
- additional: cardaic arrhythmia, seizure, HTN emergency
- resistance to tx
13
Q
urticaria tx
A
- diphenhydramine or fexofenadine
14
Q
facial or laryngeal edeam tx
A
epinephrine
15
Q
bronchospasm tx
A
- beta-2 agonists
- epinephrine
16
Q
hypertensive crisis tx
A
- labetolol
- nitroglycerin
17
Q
hypotension unresponsive to fluid tx
A
epinephrine
18
Q
pulmonary edema tx
A
lasix (furosemide)
19
Q
seizure tx
A
lorazepam
20
Q
Liver injuries
A
- most common site of injury
- most common cause of death (perhepatic hemorrhage, intraperotneal, extraperitoneal hemorrhage)
21
Q
splenic injuries
A
- most often injured in deceleration injuries
- most vascular organ
- CT is study of choice for eval of splenic trauma
22
Q
common CT findings in splenic trauma
A
- Subcapsular hematoma: low attenuation, crescent-shaped collection of fluid in supcapsular space that compresses normal splenic parenchyma
- Laceration: irregular, low attenuation defect that typically transects spleen
- Intraparenchymal hematoma: lacerations filled w/ blood; intrasplenic, rounded areas of low attenuation that may have mass effect & enlarge the spleen
- Contusion: alterations in normal homogenous appearance of spleen (mottled areas of low attenuation)
- Intraperitoneal fluid/blood: hemoperitoneum occurs w/ almost all splenic injuries also producing small amounts of blood in pelvis
23
Q
kidney injury
A
- MVC most common cause of blunt trauma
- most renal injuries will have hematuria
- contrast enhanced CT is study of choice
24
Q
shock bowel CT findings
A
- diffuse wall thickening
- increased bowel wall enhancement
- IVC/aorta smaller
- decreased splenic perfusion
- severe hypovolemia and hypotension
25
Q
bowel perforation injuries
A
- penetrating or blunt trauma
- free air w/out surrounding bowel wall
- fluid in abd cavity
26
Q
bladder injuries
A
- 70% of bladder ruptures occur w/ pelvic fractures
- 10% of pts with pelvic fractures have a bladder rupture
- CT cystogram (foley catheter under gravity) or IV contrast
27
Q
types of bladder rupture
A
- Extraperitoneal: extraluminal contrast remains around bladder, esp retropubic space; pelvic fracture w/ direct puncture of bladder
- Intraperitoneal: result of forceful blow to the pelvis w/ distended bladder; usually occurs at dome of the bladder adjacent to peritoneal cavity, contrast runs through peritoneal cavity, surrounds bowel, and extends into paracolic gutters
28
Q
urethral injuries
A
- more common in males
- blunt trauma, penetrating around urethra, or straddle fracture
- hematuria, blood at urethral meatus, inability to void
- retrograde urethrography (RUG)
29
Q
diaphragm injuries
A
- 5% of trauma
- L injuries more common than R
- herniation of content into thoracic cavity
- rarely an isolated injury
- “collar sign”
30
Q
pancreatic injuries
A
- less common
- penetrating more common than blunt
- unlikely to be isolated
- high likelihood of damage to pancreatic duct
31
Q
Pancreatitis
A
- clinical diagnosis w/ CT to find a cause (ex gallstones) or complication
- most commonly caused by alcoholism and gallstones
32
Q
acute pancreatitis on CT
A
- enlargement of all or part of pancreas
- peripancreatic stranding or fluid collections
- complications: necrosis, pseudocyst
33
Q
chronic pancreatitis CT findings
A
- continuous and irreversible usually due to alcohol abuse
- fibrosis, atrophy of gland, ductal dilatation, DM
- multiple calcifications
34
Q
localized ileus CT findings
A
- dilated loops
- usually secondary to inflammation of adjacent organ
- RUQ: cholecystitis
- LUQ: pancreatitis
- RLQ: appendicitis
- LLQ: diverticulitis
- mid abdomen: ulcer/kidney/ureteral calculi
35
Q
generalized ileus CT/XRAY
A
- entire bowel is air containing and dilated
- absence of peristalsis and continued production of intestinal secretions usually produce many long air-fluid levels in bowel
- not mechanism obstruction, so there is gas in rectum/sigmoid colon
- bowel sounds absent/hypoactive
- post op or electrolyte imbalance
36
Q
causes of small bowel obstructions
A
- adhesions
- malignancy
- hernia
- gallstone ileus
- intussusception
- IBD
37
Q
describe small bowel obstructions
A
- lesion, either inside or outside small bowel, obstructs lumen
- from point of obstruction backward, small bowel dilates from continuously swallowed air and intestinal fluid that is still produced by digestive organs
- peristalsis continues and may increase in an effort to overcome obstruction (leads to hyperactive, high pitched bowel sounds)
- as time passes, peristaltic waves empty the small bowel along the colon of their contents from point of obstruction forward
38
Q
CT findings SBO
A
- fluid filled and dilated loops of small bowel (>2.5cm in diameter) proximal to point of obstruction
- identification of transition point (dotted white arrow) which is where bowel changes caliber from dilated to normal indicating site of obstruction
39
Q
LBO clin med
A
- colon dilated to point of obstruction (sometimes possible to identify site of obstruction as last air containing segment of colon; regardless of point of obstruction, cecum is often most dilated part)
- risk of cecal rupture at 12-15cm
- small bowel not dilated
- rectum does not contain air
40
Q
LBO CT findings
A
- dilated to point of obstruction then normal in caliber distal to obstructing lesion
41
Q
Colitis
A
- inflammation of large bowel
- clinical history is key
- segmental thickening of bowel wall w/ irregular narrowing of bowel lumen due to edema
- accordion sign
42
Q
Diverticulosis
A
- herniation of mucosa and submucosa through defect in muscular layer
- generally asx but can become inflammed and bleed (most common cause of massive lower GI bleeding)
43
Q
diverticulitis CT findings
A
- colon wall thickening
- pericolonic inflammation
- can perforate or form abscess
44
Q
Appendicitis
A
- RLQ pain
- dilated appendix w/ inflammation around
- perforation occurs in up to 30% of pts
45
Q
AAA
A
- aneurysm: localized dilated of artery by 50%+ normal size
- normal aorta: 3cm
- most aneurysms occur in abd aorta inferior to the origin of the renal arteries and frequently into one or both iliac arteries
46
Q
AAA- imaging
A
- US screening test of choice
- size of an aneurysm is directly related to risk of rupture
- less than 4cm: less than 10% chance of rupture
- 4-5cm: 25% chance of rupture
47
Q
Aortic dissection
A
- convention radiographs not sensitive enough to be diagnostically relaible (widened mediastinum, left pleural effusion)
- CTA is study of choice
- left apical pleural cap of fluid/blood
- loss of normal shadow of aortic knob
- increased deviation of trachea or esophagus to R
48
Q
type A vs type B dissections
A
- A: ascending aorta, surgery
- B: descending aorta, medical management
49
Q
PID
A
- ovaries are enlarged w/ multiple cysts and periovarian inflammation
- fallopian tubes may be fluid filled and dilated (pyosalpinx)
- multi-loculated mass w/ separations
- US is image of choice; CT for complicated pts or whose HPI doesn’t strongly suggest PID
50
Q
Ovarian cysts
A
- majority of ovarian cysts in premenopausal women are functional cysts (increase follicular and corpus luteal cysts)
- dx via XR, CT, US
51
Q
differentiate follicular and corpus luteal cysts
A
- follicular: forms when non-dominant follicle fills w/ fluid and doesn’t rupture
- corpus luteal: when corpus luteum fills with fluid (corpus luteum forms after egg is expunged from dominant ovarian follicle)
