Abdominal pain and Vomiting
Try out this renal case and test your clinical knowledge. The answers are at the bottom.
A 73-year-old man presents to A&E with pain in his left lower abdomen that began two days ago. He reports that the pain comes on in waves and is the ‘worst pain he has ever experienced’. You notice that he is unable to sit still, and he produces a large vomitus while waiting in the triage area.
Past Medical History:
Hodgkin’s Lymphoma (All-clear 2003)
Tenderness in L iliac fossa
Strong dorsalis pedes and posterior tibial pulses bilaterally
PR: Soft stool, good anal tone
He is given PR diclofenac which relieves some of the pain. Some initial investigations are performed, as shown below:
Q1: Comment on the observation and urinalysis findings. What are the differential diagnosis for his presentation?
Some POC bloods are also taken.
Q2: Comment on the blood results – how does this fit in with his likely diagnosis?
He is reviewed by the A&E SHO who requests a scan:
The scan is shown below:
Image 1: Case courtesy of Dr Balint Botz, Radiopaedia.org. From the case rID: 83442 https://radiopaedia.org/articles/ct-kub?lang=gb
Q3: What is the name of this scan & what does it show?
Q4: How might you manage this patient?
Reveal the answers
Abdominal pain in an elderly man has several differentials, often split by the region.
A differential diagnosis for lower abdominal pain in a man would include:
– Ruptured AAA – this is the single most important condition to exclude (and is unlikely due to the normal abdominal examination, strong pedal pulses and normal BP)
– Mesenteric adenitis
– Ureteric colic
– Torsion of the testes
– Strangulation of a hernia
– Acute urinary retention
– Bowel obstruction/volvulus – usually LBO in the lower segment due to malignancy – his all-clear means that lymphoma is unlikely to be the culprit and there are no features of colorectal malignancy e.g. PR bleeding, weight loss etc.
– Colitis – ischaemic, infectious, inflammatory (IBD)
His urinalysis is only positive for blood, making a UTI/pyelonephritis unlikely but confirming that the source of his abdominal pain is likely related to the kidneys and urinary collecting system.
Salient points from the bloods:
– High urea
– High creatinine
– High calcium
– High PTH
– Low phosphate
– Normal K+
This suggests there is some degree of acute kidney injury due to the sharp rise in urea and creatinine that was not present previously. The normal K+ (and hypercalcaemia + low phosphate) also points away from a chronic source of kidney disease. The AKI can be further stratified by calculating the urea:creatinine ratio – in this case It is 117. A score > 100 is indicative of a pre-renal cause of the AKI, in most cases this is due to dehydration or inadequate fluid intake (also likely the cause in this case) and would be rapidly improved with a fluid bolus
The hypercalcaemia and the low phosphate can be paired with the high PTH – the cause here is primary hyperparathyroidism likely due to a solitary adenoma (a common condition in the elderly). The other key differential here would be tertiary hyperparathyroidism, but as there is no evidence of existing kidney disease or any previous secondary hyperparathyroidism this differential is unlikely. This resultant hypercalcaemia is likely to have predisposed this man to calcium-containing ureteric stones e.g. oxalate/phosphate, which is the likely source of his loin pain and haematuria. The normal uric acid level also rules out uric acid stones as a possible differential and the absence of any UTIs makes a struvite stone less likely as well.
This is a non-contrast CT-KUB which visualizes the urinary collecting system well and shows a left sided radio-opaque ureteric stone at the base of the bladder. These tend to get lodged at 3 main places – the pelvic brim, the pelvic-ureteric junction (PUJ) and the vesicoureteral junction (VUJ) – in his case it is at the left VUJ!
As mentioned earlier, his AKI is likely secondary to fluid depletion so adequate fluid resus is likely to help improve this rapidly. The management of the stone itself is complex, and is determined by a variety of factors – possible urological treatment options are summarized below:
1) Severe hydronephrosis or pyelonephritis –> Uretric (J-J stent) or Percutaneous nephrostomy
2) Stone burden <5 mm –> Watchful waiting (Tamsulosin is no longer recommended)
3) Stone burden 5 mm – 20 mm –> Percutaneous nephrolithotomy (renal pelvic stones)
or Shockwave Lithotripsy (CI in pregnancy)
or Ureteroscopy (lower renal tract stones)
4) Stone burden > 20 mm –> Percutaneous nephrolithotomy
or Medial options include thiazides for calcium containing stones as they reduce tubular calcium levels and adequate fluid intake
To get more information about the conditions mentioned in this case including diagnosis and management, have a look at our free renal notes on In2Med. Written by medical students, we have pitched them just at the right level to help you ace your exams.
Dr Amol Joshi
University of Cambridge