Dr. Chapa’s Clinical Pearls

Episode: PUR and Peppermint Oil?
Date: February 15, 2025
Host: Dr. Chapa

Overview

This episode of Clinical Pearls dives into the topic of Postpartum Urinary Retention (PUR), exploring causes, diagnosis, management, and some unconventional remedies like peppermint oil vapor. Dr. Chapa combines clinical evidence with wit and humor to provide practical tips for healthcare providers, especially in women’s health. The episode emphasizes listening to patients, clarifying diagnostic criteria, and reviewing both traditional and alternative therapeutic approaches—with a critical look at the evidence.

Key Discussion Points & Insights

1. What is Postpartum Urinary Retention (PUR)?

[00:35, 10:55]

• Definition Variance: Not a clearly defined condition; different sources use post-void residuals (PVR) from 150-200 mL (typical) up to 500 mL (controversial, "way too much urine")
• Clinical Pearl: "Just because somebody voids doesn't mean they are not retaining." (Dr. Chapa, [00:35])
• Types:
  • Overt: Clearly symptomatic (pain, inability to void)
  • Covert: Asymptomatic, detected on imaging

2. Why Does PUR Happen?

[13:35]

• Multifactorial in etiology:
  • Pregnancy hormonal changes (e.g., progesterone effect on detrusor muscle)
  • Periurethral/vaginal inflammation (especially after vaginal delivery)
  • Nerve palsy from stretching during labor
  • Surgical factors (e.g., C-section with extensions)
• Risk Factors:
  • Prolonged second stage of labor
  • Operative vaginal delivery (forceps, vacuum)
  • Anal sphincter injuries and macrosomia (lesser impact)
  • Study Cited: Systematic review (BJOG, 2012) found operative vaginal delivery carried the highest risk.

3. Diagnosing PUR

[10:55, 13:35]

• Use bedside ultrasound or bladder scan to assess bladder volume
• Typical criteria: inability to void within 4-6 hours post-catheter removal or after vaginal delivery
  • “My preference is a four hour cutoff.” (Dr. Chapa, [10:55])
• Listen carefully to patient complaints, especially persistent pain not explained by other causes

4. Management Options

a. Patience!

[14:54, 24:05]

• “This thing resolves within the first three days in almost 97–98% of cases.”
• Persistent PUR (>5 days): rare, 0.05–0.18% incidence
• Mainstay: Observation, with temporary use of indwelling catheters if needed (ideally no longer than 24 hours to avoid infection)
• Prefer monitoring in hospital to home foley placement

b. Traditional Medications

[22:01]

• Bethanecol: FDA-approved for postpartum, non-obstructive urinary retention
  • Mechanism: Acetylcholine-like, stimulates detrusor muscle contractions
  • Data: "Studies that have looked at this for over 30 years are very meh. It's just not great." (Dr. Chapa, [22:01])
  • “If you just wait enough, like 3 days, maybe 5 at max, it’s gonna go away by itself.” (Dr. Chapa, [22:01])
  • Side effects: Flushing, tachycardia, diarrhea, urinary urgency
  • Use with caution in breastfeeding; safety data scant
• Alpha blockers (Tamsulosin/Flomax): Sometimes tried, but evidence is poor and use is off-label; no data for lactating patients

c. Peppermint Oil Vapor

[28:18]

• Used in complementary/alternative medicine as a vapor (well-diluted, never direct application to the skin)
• Method: A few drops in water ("in a hat"), patient sits over vapor for ~10 minutes
• Level 1 evidence (randomized trial) published May 2024 (AOWN journal)
  • N=69; 63% in peppermint group voided spontaneously vs. 37% of control
  • “Wasn’t statistically significant, likely because the sample size was way too small.” (Dr. Chapa, [31:52])
• Limitations: Small sample size, poor blinding (you can smell peppermint!), lack of management participation

Key Quote:
"Peppermint oil increased spontaneous voiding. However, findings were not statistically significant to support it in clinical use… further research with a larger sample size is warranted." ([32:12], quoting study authors)

• Dr. Chapa’s Take:
  "It can’t hurt. It can possibly help. Above all that, hey, peppermint smells good. So if you want to try that, knock yourself out." ([33:10])

• Cautionary Tale (Humorous):
  Do NOT apply undiluted peppermint oil (or other irritating substances) to genital skin—Dr. Chapa recounts a memorable patient anecdote involving “Red Hots” candy and oral sex:
  “...meaning well, trying to give her a little extra, you know, zing, zing, zang, zang… she was still tingling like two days later.” ([28:18])

Notable Quotes & Memorable Moments

• On the blurred line between mainstream and alternative medicine:

  “The line between functional medicine and traditional medicine used to be a true line in the sand, but that line… is now pretty blurry.” ([04:05])

• On the definition quagmire:

  “Somebody recently published… that 500 ml cutoff… out of the Journal of Maternal and Fetal Medicine in December of 2023. Now, I’m not in line with that… most people would disagree.” ([06:15])

• On the effect of delayed recognition:

  “The longer there’s a time to diagnose postpartum urinary retention, the longer the recovery can be… it will, it’s just going to take longer.” ([25:55])

• Signature humor:

  “Just get a dog, man. Just get a dog. Dogs don’t do that. Anyway, let’s get into PUR and its remedies.” ([09:30])

• On peppermint oil’s limitations:

  “Can you not smell peppermint oil? … it was ‘blinded’ but… you can smell peppermint.” ([31:00])

• On what to tell patients:

  “The chance that this still persists after five days… is 0.05% up to 0.0.18%. Super, super small.” ([27:45])

Timestamps for Important Segments

| Timestamp | Segment | |-----------|------------------------------------------------------------------------| | 00:35 | Introduction to PUR and humorous opening | | 04:05 | Mainstream vs. complementary medicine | | 06:15 | Diagnostic definitions and controversies | | 09:30 | Clinical pearls: types of PUR, diagnostic suggestions | | 10:55 | PUR: overt vs. covert, importance of listening to patients | | 13:35 | Elaboration on diagnosis, risk factors, and pathophysiology | | 14:54 | Management: patience, duration, when PUR is considered “persistent” | | 22:01 | Medications: bethanecol, Flomax, efficacy and safety | | 25:55 | Management strategy, patient reassurance | | 27:45 | Persistence rates info, what to tell patients | | 28:18 | Peppermint oil vapor data, clinical experience, “Red Hots” anecdote | | 31:00 | Peppermint oil RCT limitations, sample size, blinding | | 32:12 | Academic summary from study authors, Dr. Chapa’s interpretation | | 33:10 | Final take: “It can’t hurt. It can possibly help.” |

Summary Table: PUR Management Options

| Option | Evidence Quality | Pros | Cons / Risks | |------------------------------|-----------------------------------|-----------------------------------------------|----------------------------------------------| | Observation / Catheterization| Strong clinical support | High spontaneous resolution rate | Temporary discomfort, infection risk | | Bethanecol | Level 1, but "meh" data | FDA approved | Side effects, unclear safety for lactation | | Alpha blockers (Flomax) | Poor quality, off-label | Theoretical benefit | Little evidence, not recommended in lactation| | Peppermint Oil Vapor | Level 1 (small, underpowered RCT) | Non-invasive, pleasant scent | No proven benefit, study limitations |

Tone & Language

Dr. Chapa delivers information in a friendly, conversational, and sometimes cheeky manner—using anecdotes, pop culture references, and humor to keep the episode engaging and memorable.

For Listeners:

If you encounter a postpartum patient with urinary difficulties, remember:

• PUR is mostly temporary and resolves with patience and supportive care.
• Diagnostic uncertainties abound; use clinical judgement, and always listen to your patient!
• Medications (bethanecol, alpha blockers) are rarely necessary and not well-supported by evidence.
• Peppermint oil vapor is safe to try as a vapor—not a cure, but possibly helpful, and certainly aromatic.
• “Just don’t put Red Hots or undiluted peppermint anywhere it shouldn’t go!” ([28:18])

See you next time for more Clinical Pearls!