Request Card Task ANSWERS

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Allan Allison
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1 Request Card Task ANSWERS Medical Student Workbook Author: Dr Sam Leach, SpR

2 Case 1 What differential diagnoses are most likely? Which investigation is most appropriate?

3 Case 1 The most likely diagnosis here is renal colic +/- ureteric obstruction. Haematuria Loin to groin pain Bloods may indicate dehydration as a cause. Other differentials: Appendicitis but you would expect some guarding Strangulated hernia you may find this on examination.

4 Case 1 Most appropriate investigation is CT KUB: Reliably diagnose renal calculi Evaluates ureter and kidney for signs of obstruction. May provide alternative diagnosis if no renal calculi present Non- contrast so can be performed safely with abnormal renal function

5 Case 1 CT KUB with renal pelvis and proximal ureteric dilatation (red arrow) secondary to obstruction by calculus with associated perinephric stranding (white arrows)

6 Case 1 Other investigations you may have considered: AXR may reveal calculus but less reliable than CT and will not show ureteric obstruction USS abdomen would be able to evaluate obstruction if progression to hydronephrosis but would not be able to diagnose number/ size/ location of all calculi IVU still used as an alternative to CT KUB in some hospitals, however less reliable at finding calculi, time- consuming and has the disadvantage of using iodinated contrast.

7 Case 2 What differential diagnoses are most likely? Which investigation is most appropriate?

8 Case 2 The most likely diagnosis here is cauda equina syndrome with likely causes being either malignancy from previous breast cancer or disc prolapse. Bilateral leg weakness and pain often asymmetrical Saddle anaesthesia Urinary retention/sphincter disturbance Differential diagnoses MS, transverse myelitis Traumatic cord transection unlikely as no immediate symptoms

9 Case 2 Most appropriate investigation here is MRI spine Only modality to accurately visualise nerve roots and cauda equina Will be able to characterise cause of nerve root compression Allows planning of surgery No ionising radiation Will be able to identify other causes of these symptoms

10 Case 2 Axial T2 Axial T2 Sagittal T2 Compression of the conus/cauda equina by collapse of T12 (red arrow) secondary to bone metastasis. Arrowhead indicates deviation of the cauda equina rootlets. Curved arrow shows occlusion of spinal canal by displaced, abnormal bone

11 Case 2 Other investigations you may have considered: Spinal X- ray may indicate fracture or intervertebral narrowing but won t identify points or cause of Pelvic x- ray may identify pelvic fracture or other trauma but again not useful in identifying nerve root damage or cauda equina. CT best modality for characterising the configuration of fractures and may show metastatic process but not usually able to accurately identify cord compression.

12 Case 3 What differential diagnoses are most likely? Which investigation is most appropriate? What problem might this investigation pose in this patient?

13 Case 3 The most likely diagnosis here is pulmonary embolus which may well be massive given that the patient has unstable BP Pleuritic chest pain Hypoxic on high O2 Immobility with long bone fracture Differential diagnoses Pneumothorax less likely with normal respiratory examination Pulmonary oedema less likely with normal examination

14 Case 3 Most appropriate investigation here is CT pulmonary angiogram: Quick imaging technique Able to identify amount/ location of thrombus Would also help rule out other differentials Can indicate right heart strain

15 Case 3 CT pulmonary angiogram demonstrating saddle embolus, seen as a dark filling defect, at division of pulmonary trunk (red arrow)

16 Case 3 Other investigations you may have considered: CXR May rule out differentials but unable to reliably diagnose PE. With lack of chest signs and just rib fractures on admission CXR would likely be reasonable to move straight to CTPA. V/Q (Ventilation/ Perfusion) scan slow investigation so not appropriate with acutely unwell patient and less reliable. Pulmonary angiogram complex procedure, no longer performed in most hospitals and would not rule out differentials.

17 Case 3 What problem might this investigation pose?: CTPA is a contrast examination. This patient has a history of diabetes which predisposes to renal disease We have no recent results for egfr Ideally we would have a baseline level for this patient from previous blood results egfr should be at >30 for contrast examinations

18 Case 4 What differential diagnoses are most likely? Which investigation is most appropriate?

19 Case 4 The most likely diagnosis here is an acute subdural haematoma (the hypoxia may be due to inability to protect their airway or atelectasis from a long lie). Evidence of fall and head injury Deranged INR Reduced GCS Possible differentials might include: Haemorrhagic stroke though no clear evidence of focal neurology Hypoglycaemia Post- ictal

20 Case 4 CT head showing acute subdural haematoma (red arrow) with mass effect and midline shift

21 Case 4 Other investigations you may have considered might be: Skull x- ray would not be able to characterise haemorrhage or usually identify it. Largely redundant if CT head is appropriate as skull can be visualised on bone windows for fractures MRI Accurate in identifying haemorrhage but not as quick as CT and therefore less appropriate in this situation. Would be useful if no abnormality found on CT as can identify parenchymal pathology more effectively.

22 Long case Fill out the request card for this case then read through the example card and discussion

23 Case History Fill out the request form for this patient with the most appropriate investigation, including differential diagnoses

24 Example request card St St St Elsewhere NHS Trustospital NHS Trust

25 Discussion There are several other less likely possible differentials which could also be considered: Pyelonephritis Early appendicitis Pancreatitis Reflux disease +/- peptic or duodenal ulcer not normally investigated in acute setting unless perforation/ hematemesis Perforation of ulcer is unlikely given the normality of other observations, the lack of generalised guarding and the lack of hematemesis but should always be considered

26 Discussion Regarding the other findings from the history: Mild tachycardia is most likely to be related to pain Amylase rise is small and can be associated with cholecystitis Gamma GT is elevated but may reflect a high alcohol intake the other LFTs are normal Decreased egfr is most likely to be associated with dehydration the patient has been vomiting and passed lots of urine, most likely related to alcohol intake

27 Discussion The most appropriate investigation is ultrasound: Reliable at identifying gallstones and cholecystitis No ionising radiation Can also assess liver and common bile duct at same time for complications of gallstone disease Can attempt to visualise appendix and check for inflammation, as well as kidneys for pyelonephritis Can demonstrate free fluid in the abdomen indicating other pathology and possibly need for further investigation

28 Discussion Ultrasound of acute cholecystitis with gallstones (red arrow) and wall thickening (yellow arrows indicate wall thickness greater than 3-4mm).

29 Discussion Other investigations you may have considered: Erect Chest x- ray though perforation does not seem likely, this may be acceptable to rule out perforation As it is ionising radiation though it would be necessary in most situations to rule out pregnancy first This modality would be unlikely to give you any further information about the cause of the symptoms Abdominal X- ray high dose of radiation that is unlikely to give further information Gallstones unlikely to be visualised - >90% are radiolucent Erect chest x- ray more useful and lower dose to rule out perforation No indication of obstruction in the history

30 Discussion Abdominal CT Will be able to give most information and identify most of these differentials High dose and not necessary in a stable patient, with a diagnosis which could be confirmed with US If pancreatitis is strongly suspected then may be used to look for complications May be necessary if patient deteriorates or becomes unstable. Non- radiological endoscopy Can be used to look for ulcers and evidence of reflux but would not exclude or identify differential diagnoses

31 The End

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