Viva · Specialty
Emergency and Trauma Viva Questions
Oral-exam style questions and answers on emergency and trauma for MD, DNB and super-specialty practical examinations. Each answer links back to the playbook or Library entry it was written from.
- What CT findings indicate closed-loop small bowel obstruction?
- A U-shaped or C-shaped dilated bowel loop, radial distribution of mesenteric vessels converging toward a torsion point, beak sign at the transition, and whirl sign of twisted mesentery. Closed-loop obstruction carries high risk of strangulation and requires emergency surgery.
- What is the significance of pneumatosis intestinalis in the acute abdomen?
- Pneumatosis intestinalis indicates gas within the bowel wall and in the setting of acute abdomen suggests bowel wall compromise from ischaemia, infarction or necrosis. It is a surgical emergency until proven otherwise, particularly when accompanied by portal venous gas.
- What is the Hinchey classification used for?
- The Hinchey classification grades the severity of complicated acute diverticulitis: Stage I is pericolic abscess, Stage II is pelvic or distant abscess, Stage III is purulent peritonitis, and Stage IV is faecal peritonitis. Stages III and IV require emergency surgical intervention.
- When is contrast-enhanced CT optimally performed in acute pancreatitis?
- At least 72 hours after symptom onset, as earlier CT may underestimate the extent of pancreatic necrosis. CT is primarily indicated when the patient fails to improve clinically or when complications such as necrosis, abscess or vascular involvement are suspected.
- What is Rigler triad and what does it indicate?
- Rigler triad consists of pneumobilia, ectopic gallstone (typically at the ileocaecal valve) and small bowel obstruction. It is pathognomonic of gallstone ileus, where a large gallstone erodes through a cholecystoenteric fistula and impacts in the terminal ileum.
- What is the ASPECTS score and what does a score below 7 indicate?
- ASPECTS assigns 10 points to MCA territory regions on non-contrast CT or DWI. Each region showing ischaemic change subtracts 1 point. A score below 7 indicates a large established infarct core and is associated with poorer functional outcomes after thrombectomy.
- How do you distinguish epidural from subdural haematoma on CT?
- Epidural haematoma is biconvex (lentiform), limited by sutures but can cross the midline if the sagittal sinus is stripped. Subdural haematoma is crescentic, crosses sutures freely but is limited by dural reflections such as the falx and tentorium.
- What is the imaging investigation of choice for suspected spinal cord compression?
- MRI of the entire spine with T1, T2 and STIR sequences is the investigation of choice, as it demonstrates cord signal change, epidural collections, disc herniation and metastatic disease with superior soft-tissue contrast.
- What is the significance of the spot sign on CTA in intracerebral haemorrhage?
- The spot sign represents active contrast extravasation within an acute intracerebral haematoma on CTA and is a strong independent predictor of haematoma expansion, increased mortality and poor functional outcome.
- Describe the three-column model of spinal stability.
- Denis three-column model: anterior column (anterior longitudinal ligament and anterior two-thirds of vertebral body/disc), middle column (posterior one-third of body/disc and posterior longitudinal ligament), posterior column (pedicles, facets, laminae and posterior ligamentous complex). Disruption of two or more columns indicates instability.
- What is the Stanford classification of aortic dissection and why does it matter?
- Stanford Type A involves the ascending aorta regardless of distal extent and requires emergency surgical repair due to risk of tamponade, coronary malperfusion and rupture. Type B involves only the descending aorta and is managed medically unless complicated by malperfusion, rupture or rapid expansion.
- What CT finding indicates right heart strain in pulmonary embolism?
- An RV to LV diameter ratio greater than 1 on axial CT, often with interventricular septal bowing toward the LV, IVC contrast reflux and PA enlargement. This indicates haemodynamically significant PE and adverse prognosis.
- How does intramural haematoma appear on CT?
- On non-contrast CT, intramural haematoma appears as a crescentic or circumferential hyperdense thickening of the aortic wall exceeding 5 mm. On contrast-enhanced CT, there is no enhancement within the thickened wall and no intimal flap or false lumen flow.
- What is the clinical significance of tension pneumothorax and why is it not primarily a radiological diagnosis?
- Tension pneumothorax is a clinical diagnosis characterised by hypotension, tracheal deviation, absent breath sounds and distended neck veins. It requires immediate needle decompression before imaging, as waiting for radiograph confirmation can be fatal.
- What are the CT signs of Boerhaave syndrome?
- Pneumomediastinum, left-sided pleural effusion, subcutaneous emphysema, and oesophageal wall thickening or disruption. CT with oral contrast demonstrates extravasation confirming the perforation site, most commonly the left posterolateral distal oesophagus.
- What is the difference between CTDIvol and DLP?
- CTDIvol represents the average radiation dose within the scan volume in milligray and reflects scanner output for a given protocol. DLP is CTDIvol multiplied by scan length in centimetres, expressed in mGy·cm, and estimates the total radiation energy delivered for the entire examination.
- How does iterative reconstruction reduce CT dose?
- Iterative reconstruction algorithms model the physics of photon detection and reduce image noise through repeated forward and back projections. This allows diagnostic image quality at lower tube current or voltage settings, enabling 20-50% dose reduction compared to traditional filtered back projection.
- Why is lowering tube voltage beneficial for contrast-enhanced CT?
- Lowering kVp from 120 to 100 or 80 brings the mean photon energy closer to the iodine k-edge at 33 keV, increasing photoelectric absorption and thus iodine contrast-to-noise ratio. This allows either reduced contrast volume or improved vessel conspicuity at lower radiation dose.
- What is the role of dual-energy CT in reducing trauma CT dose?
- Dual-energy CT can generate virtual non-contrast images from a contrast-enhanced acquisition, potentially eliminating the need for a true non-contrast phase. It also provides iodine maps for detecting active haemorrhage and metal artefact reduction, all from a single acquisition.
- How is effective dose estimated from DLP?
- Effective dose in millisieverts is calculated by multiplying DLP by a body-region-specific conversion factor (k-factor). For example, the k-factor for abdomen-pelvis is approximately 0.015 mSv per mGy·cm. This provides a population-level estimate of stochastic risk, not an individual patient dose.
- What are the components of the RUSH examination?
- RUSH evaluates three categories: the pump (cardiac contractility, pericardial effusion, RV size), the tank (IVC volume status, pericardial fluid, pleural effusion, peritoneal free fluid), and the pipes (aortic diameter for aneurysm, deep veins for DVT). It systematically identifies the cause of undifferentiated shock.
- What is the lung point sign and why is it important?
- The lung point sign is the location where normal lung sliding intermittently returns at the boundary of a pneumothorax on real-time ultrasound. It is 100% specific for pneumothorax and helps confirm the diagnosis when lung sliding is absent.
- What is the minimum volume of free fluid detectable by eFAST?
- Approximately 200-250 mL of free peritoneal fluid is needed for reliable detection in the most dependent windows. Smaller volumes may be missed, particularly in the supine trauma patient.
- Why should a negative eFAST not exclude intra-abdominal injury?
- eFAST has limited sensitivity for small-volume haemorrhage, retroperitoneal injuries, hollow viscus perforation and early solid-organ contusions. It is a rapid screening tool and must be supplemented by CT when clinical suspicion persists.
- What ultrasound findings suggest acute cholecystitis?
- Gallbladder wall thickening greater than 3 mm, pericholecystic fluid, impacted gallstone in the neck, sonographic Murphy sign (focal tenderness over the gallbladder) and gallbladder distension. No single sign is diagnostic; the combination increases specificity.
- What are the four windows of the eFAST examination?
- Right upper quadrant (Morison pouch), left upper quadrant (splenorenal recess), pelvis (pouch of Douglas or rectovesical pouch) and subxiphoid pericardial view. Bilateral anterior chest views are added for pneumothorax assessment.
- Where does blunt thoracic aortic injury most commonly occur?
- At the aortic isthmus, just distal to the left subclavian artery, where the mobile aortic arch meets the fixed descending aorta anchored by the ligamentum arteriosum.
- What CT finding in blunt solid-organ trauma most directly indicates the need for angioembolisation?
- Active contrast extravasation (contrast jet or blush) on arterial or portal venous phase CT, indicating ongoing haemorrhage that is unlikely to tamponade spontaneously.
- Why is delayed-phase CT important in renal trauma?
- Delayed imaging at 5-10 minutes allows excretion of contrast into the collecting system, enabling detection of collecting system laceration, ureteric injury or urinoma that may not be visible on portal venous phase alone.
- What is the barcode sign on lung ultrasound?
- On M-mode, absence of lung sliding produces parallel horizontal lines (barcode or stratosphere sign) instead of the normal granular seashore pattern, indicating pneumothorax. The lung point sign, where normal sliding intermittently returns, is specific for pneumothorax.
- What is the Rotterdam CT score and what does it predict?
- It is an additive admission head CT score, ranging from 1 to 6, derived by Maas and colleagues in 2005 to predict six-month mortality and outcome in moderate to severe traumatic brain injury.
- Name the four CT components scored.
- Basal cistern status, midline shift, presence or absence of an epidural mass lesion, and intraventricular blood or traumatic subarachnoid haemorrhage.
- How are the basal cisterns and midline shift scored?
- Basal cisterns score 0 if normal, 1 if compressed and 2 if absent. Midline shift scores 0 if absent or 5 mm or less, and 1 if greater than 5 mm.
- Why does absence of an epidural haematoma score a point?
- Because an epidural haematoma is an evacuable extra-axial lesion carrying a comparatively better prognosis, so its absence implies the mass effect arises from diffuse or parenchymal injury, which predicts worse outcome.
- Why is a constant of 1 added?
- It shifts the range from 0 to 5 up to 1 to 6, so the score maps numerically onto the six grades of the Marshall classification and no patient scores zero.
- How does the Rotterdam score differ from the Marshall classification?
- Marshall assigns a single anatomical category based on diffuse injury grade and evacuated versus non-evacuated mass lesions, whereas Rotterdam scores individual CT predictors independently and sums them, handling mass lesions and subarachnoid or intraventricular blood better.
- Which CT should be scored?
- The admission scan. Repeat imaging after clinical deterioration or after decompressive surgery alters the components and does not carry the original prognostic estimate.
- How should the score be used clinically?
- As a group-level prognostic descriptor for outcome prediction, research stratification and audit. It is not a triage rule or an indication for surgery in an individual patient, and management decisions rest on clinical status and intracranial pressure.