Here are some round-up pearls from 2 great cases this week!
Case summary 1: On Monday, Jill presented the case of an elderly man with a history of obstructive struvite stones and Proteus bacteremia s/p nephroureterostomy tube, who presented with septic shock from recurrent/persistent struvite stones.
- Interestingly, Proteus contributes to recurrent stone formation in 2 ways:
- Urease splitting bacteria generate high urinary pH levels
- The body can’t clear the urinary tract of the bacteria because they are embedded in the stones.
- Other reasons to have alkaline urine:
- (1) urinary tract infection (Proteus and others)
- (2) metabolic or respiratory alkalosis
- (3) failure of acidification (renal tubular acidosis)
- (4) ingestion (alkaline diet [a fad diet right now!], medications like sodium bicarbonate).
- This is important, as alkaline urine can precipitate struvite and calcium phosphate stone formation
- Acidify urine with cranberry juice or betaine
- In contrast uric acid, cystine and calcium oxalate [most common in adults] stones precipitate in acidic urine (prevent with alkalinzation of urine via dietary changes or calcium citrate/K citrate
Here’s a great review on nephrolithiasis: https://www.aafp.org/afp/2011/1201/p1234.html#afp20111201p1234-c1
- A nephroureterostomy tube has both internal (via ureter) and external (via nephrostomy tube) drainage, so lack of external drainage does not necessarily indicate tube dysfunction.
Here’s a diagram for the visual-minded:
Case summary 2: At intern report, we discussed a patient who was post-op day #1 s/p an ankle fusion who developed chest pain and was found to have diffuse ST depressions and STE in aVR. This got us to talking more broadly about ACS and “STEMI equivalents.”
- Moral of the story: new or presumed new LBBB may not predict ACS.
- 2 retrospective studies looked at ~900 and ~300 patients with new or presumed new LBBB and concluded
- Those patients with new or presumably new LBBB are a high-risk group (older, higher TIMI scores, more cardiomyopathy).
- However only ~1/3 had acute MI, while the remaining patients had other cardiac or non-cardiac diagnoses
Here’s a Medscape article summarizing the literature on LBBB as a STEMI equivalent: https://www.medscape.com/viewarticle/753695_1