Author: Hiro Miyagi OSU MS4 // Editor: Michael Barrie OSU EM Attending
Medical Student Corner – When do kidney stone patients need immediate intervention?
A 51yo female presents with an acute episode of severe right sided back pain with nausea and vomiting. Patient has a past medical history of HTN and chronic back pain. The pain is intermittent, described as sharp and stabbing 10/10 pain. She has not been able to tolerate any liquids since the onset of pain. The patient denies fevers or chills, with no recent infections or illnesses. No dysuria, but with mild urinary frequency. She has a past surgical history of appendectomy 30 years ago.
Vital signs: Afebrile, HR: 96, RR: 16, bp: 140/98, SPO2: 100% on room air.
On exam, the patient appears restless, abdomen is soft but tender on the RLQ. Heart and lung exams are unremarkable. There is no CVA tenderness.
Labs: Creatinine: 0.98, wbc: 11, Hgb: 13.4, UA shows trace blood, positive nitrites, negative leukocytes, many squamous epithelial cells.
CT scan: 3.5mm x 4mm obstructing R ureteral stone with mild right hydronephrosis
Patients with kidney stones are no strangers to emergency physicians. While the differential for flank pain can include renal or ureteral stones, pyelonephritis, lobar pneumonia, AAA, hydronephrosis, and gynecologic causes among many others, I wanted to specifically discuss flank pain secondary to kidney stones and what the indications are for prompt intervention.
During my emergency medicine rotation, I was taught that disposition is one of the most important questions to answer while in the ED. Can the patient go home? Do they need further studies? Do they need prompt intervention? Below I have reviewed the indications for prompt intervention in kidney stone patients.
Indications for prompt intervention
- Prolonged complete or high grade unilateral urinary obstruction.
- Any degree of bilateral urinary obstruction.
- Any degree of urinary obstruction in a solitary kidney.
- Any degree of urinary obstruction with urinary infection or sepsis.
- Any degree of urinary obstruction with a rising creatinine.
- Symptoms refractory to medical management – Inability to tolerate oral intake because of severe nausea or vomiting, or severe pain not controlled by oral analgesics.
Can this patient go home? This patient has positive nitrites suggesting that she has a UTI which is a definite indication for a stone intervention. But wait– upon closer inspection, we can see that her UA is contaminated with many squamous epithelial cells. A repeat UA was ordered (consider straight catheterization if repeat UA is contaminated). On repeat testing nitrites were negative. In an otherwise healthy female with a 4mm ureteral stone, she has a greater than 60% chance of passing the stone with time. Patients should be prescribed pain medications – NSAIDs, Tylenol, and consider opiates. Consider alpha-antagonists such as tamulosin especially when kidney stones are larger than 6mm. And like nearly all ED patients we send home, recommend aggressive fluid hydration.
The next time you see a kidney stone patient, I hope that review of these indications can help you determine the disposition of the patient.
After Toradol 15mg IV and oral Tylenol, the patient’s pain is controlled and she is now able to drink some water. The patient felt comfortable to manage her symptoms at home, and was discharged with a urine strainer and urology follow up as needed.
American Urological Association-Surgical Management of Stones: AUA/Endourology Society Guideline, http://www.auanet.org/guidelines/surgical-management-of-stones-(aua/endourological-society-guideline-2016).
American Urological Association-Medical Student Curriculum: Kidney Stones, https://www.auanet.org/education/auauniversity/medical-student-education/medical-student-curriculum/kidney-stones.