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Symptom sorter – Loin pain

The third in our new series of abridged chapters from the recently expanded and updated Symptom Sorter (sixth edition), which gives a grassroots analysis of common presentations in primary care

The GP overview

Doctors may disagree – with patients and among themselves – about where exactly the ‘loin’ is. For the purposes of this chapter, it is the area between the lower ribs and the pelvis, anteriorly or posteriorly. Loin pain is a common acute or subacute presentation, with patients tending to assume that the symptom represents a renal problem. Occasionally, they are correct. But a musculoskeletal aetiology is much more likely, and there are other possible causes to trip up the unwary.

Differential diagnosis


• Acute musculoskeletal pain.

• Renal or ureteric stone.

• Acute pyelonephritis.

• Rib pain.

• Shingles.


• Gynaecological causes such as ectopic pregnancy, PID, ruptured or torted ovarian cyst.

• Gastrointestinal causes such as appendicitis, biliary colic.

• Other urological causes in men such as epididymitis and prostatitis.

• Pelvi-ureteric obstruction.

• Radicular pain (possibly from osteoarthritis or disc prolapse).


• Leaking abdominal aortic aneurysm.

• Retroperitoneal fibrosis.

• Renal infarction.

• Renal tumour (either directly or from a consequent blood clot in the ureter).

• Acute papillary necrosis.

• Factitious (addicts might report loin pain if they are seeking opioids).

• Idiopathic loin pain haematuria syndrome.

Possible investigations


Urinalysis, MSU.


U&E, sieving urine, renal imaging (non-contrast helical CT is the investigation of choice in suspected renal/ureteric colic; depending on how acute the presentation is, and on local guidelines, abdominal X-ray or ultrasound may be helpful. Renal imaging may be required in acute pyelonephritis, possible renal tumour or pelvi-ureteric obstruction).

Small print

A metabolic screen may be needed (usually performed in secondary care); other hospital-based investigations might be urological, gynaecological or gastrointestinal.

Top tips

• Remember that many patients fear kidney problems. They may value reassurance that all is well renally as much as your positive diagnosis of musculoskeletal pain.

• Take care during busy telephone triaging sessions – be sure to check that the apparently simple cystitis isn’t actually a developing case of acute pyelonephritis.

• The absence of microscopic haematuria does not rule out renal or ureteric colic but should certainly prompt a consideration of alternative diagnoses.

• Patients with genuine renal or ureteric colic tend to writhe about in pain.

• Think of shingles, particularly in elderly patients with an otherwise unexplained short history of burning loin pain, and warn them of the possibility of a rash developing – the pain may precede the skin manifestations by a few days.

Red flags

• Beware of a first diagnosis of renal or ureteric colic (especially left sided) in older men – a leaking abdominal aortic aneurysm can cause similar symptoms.

• Some cases of renal or ureteric colic can be managed – at least initially – in the community. But those with fever, prolonged or unresponsive pain, or known renal compromise should be admitted.

• Acute pyelonephritis in men and children, and recurrent episodes in women, require investigation to exclude any underlying urological problem.

• Be cautious about using strong analgesics for possible renal or ureteric colic in patients with histories of drug addiction – this used to be a favoured way to engineer a free opioid fix, although the increasing use of diclofenac as the urgent treatment of choice has reduced this problem.

Dr Keith Hopcroft is Pulse’s clinical adviser and a GP in Basildon, Essex


John Graham Munro 10 December, 2020 9:18 pm

Go down a couple of notches and you get ”pain in the butt”
Is this the same Dr/ Keith Hopcroft from way back?