Clinical Case 073: Sorting out the RIF raff

This post is dedicated to Dr Andre ( @keeweedoc ) who has just divorced his appendix with the aid of a laparoscope. [why do surgeons do lap appys in fit, young men with clear diagnoses? ]  RIF in peace Andre.

In my shop RIF pain is common – as it is everywhere.  The unique thing about the tropical northern RIF pain though is that all those nice suburban appendixes are diluted out by an astoundingly high rate of PID / salpingitis.  It can be really tough to pick who needs an operation and who needs antibiotics +/- an operation for PID.  Our surgeon did an audit and found that ~ 50% of peritoneal swabs taken from “appendix” cases were positive for an STI!

Heres the case.  20 yo woman presents with 2 day history of increasing RIF pain.  She has been unwell with a low-grade fever, 1 x vomit and anorexia.  No urinary sxs or PV discharge.  The pain was suprapubic initially but now more localised to the RIF. 

She has had 3 confirmed episodes of STI in the last 3 years – and was treated for gonorrhea 3 months ago without any proof of cure documented.  Examination is as expected – tender with some garding in the RIF.  Urine is clear and HCG negative.  pelvic exam revelas some tenerness on the right adnexal area – but is this really helpful in discriminating an appendix from a tube in this situation?

So what to do?  Bloods are never useful in this scenario – we need images.  So being me I have started doing bedside ED US in this common scenario to try and sort out the diagnosis without resorting to large doses of radiation in patients who will likely have the same presentation on a recurrent basis.

To be honest – this is not as easy as it sounds when you read the papers and watch the US Podcast on the topic.  More than most scans I do – I walk away a lot of the time unconvinced that it will change my management.  BUT – and here is the BUT… aside from a little time there is not much to lose by having a gnader at the RIF and pelvis to see if you can make the diagnosis in ED.  Here is my basic clinical algorithm for RIF pain in this situation:

  1. Is it a really good story for appendix with a convincing exam?
  2. Is it likley that there might be PID / salpingitis on clinical probability?
  • If you say (1) Yes and then (2) No to these questions – call the surgeons.  I scan her – if it is obvious then great, the surgeons will be happy to procede. If I cannot find the appy on US – then it is the surgeons call.
  • If it is (1) Yes and (2)Yes : then this is tough – an US might clinch the diagnosis, although a lot of the time I find a bit of pelvic free fluid and still don’t know which way to go.  Laparoscopy is probably the next move for this group.
  • If (1) No and (2) Yes – then I call the Gynae instead.  US might show something in the adnexa, but a negative scan in  my hands doesn’t exclude much a t all.  Usually we give PID cover ABs, watch and wait.  A formal scan with optimal prep and a better sonographer helps.
  • If you answer (1) No and (2) No ? I scan them (as always) but with a low pre-test probability fro both PID and appy I would need a reallly convincing image to make me jump at either diagnosis.  Watchful waiting and some endocervical swabs will hopefully make things clearer in the fullness of time.

Glad you asked!

The toughest part of the scan involves actually identifying the appendix – they come in varieties including: long, short, retrocaecal and invisible!

You want to identify a blind-ending tubular structure in the RIF. Measure it in long and short axis: 6 – 7 mm quoted as normal diameters.

Appendicitis – look for:

  1.  loss of peristalsis,
  2. non-compressibility,
  3. increased vascular flow,
  4. might see a faecolith in the lumen 
  5. the classic is a “double lumen” sign as shown in the above transverse image
  6. Free fluid in the pelvis is not specific (esp with PID on the list)!

Get well soon Andre, and leave some jelly for the other kids mate!






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