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Bone Wizardry — Reproductive

The Discharge Detective

Clue cells or trichomonads? Gray or green? They all blur together until you know the trick.

Section 1

The Lineup

Tap a card to flip it and read the backstory. Know your villains.

NOT an STI
🦠
Bacterial Vaginosis
Gardnerella vaginalis
Weapon Thin, gray, fishy discharge
pH
Whiff Test Positive 💨
Treatment Metronidazole
🔎 CLUE CELLS
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Why BV Happens
The Bouncer Analogy
Lactobacillus is the bouncer of the vagina. It makes lactic acid, keeping pH low (~4.0) and bad bacteria out.🔑The bouncer keeps it tight under 4.5. When he leaves, anything gets in.
What Goes Wrong
BV = the bouncer left. Gardnerella and other anaerobesBacteria that thrive without oxygen. They produce amines (fishy smell) as metabolic byproducts. move in. Without Lactobacillus, pH rises above 4.5.
Why Clue Cells?
Gardnerella literally coats the surface of vaginal epithelial cells. The cell edges look stippled or blurred because they're covered in bacteria. That's a clue cell — the cell is giving you a clue it's been colonized.🔑Gardnerella → Gray discharge. Clue cells = coated cells giving you a clue.
Clue cells — bacteria coating vaginal epithelial cells
See the blurry, stippled edges? That's Gardnerella coating the cell surface. Clue cells in BV. Dr Graham Beards, CC BY-SA 4.0. Source
Why Metronidazole?
Metro kills anaerobes by entering the cell and damaging their DNA. It's activated inside anaerobic organisms — so it selectively destroys the overgrowth without nuking everything.
NOT an STI
BV is a flora shift, not an infection someone gives you. No partner treatment needed. Risk factors: douching, new partners (disrupt flora), antibiotics.
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STI ⚠
🦠
Trichomoniasis
Trichomonas vaginalis
Weapon Green-yellow, frothy
pH
Classic Sign Strawberry cervix 🍓
Treatment Metro + TREAT PARTNER
🔎 MOTILE TRICHOMONADS
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Why Trich Is Different
Not Bacteria
Trich is a flagellated protozoan — a single-celled organism with a tail. It's an actual parasite, not a bacterial overgrowth. That's why it's an STI.
Why It Looks Different on Microscopy
On wet mount, you see pear-shaped organisms darting around with visible flagella. They're MOVING. Clue cells don't move — they're just epithelial cells with stuff stuck to them.
Trichomonas vaginalis — pear-shaped flagellated protozoan
See the pear shape and the tail (flagellum)? These dart around the slide — they MOVE. T. vaginalis, phase contrast. Dr Graham Beards, CC BY-SA 3.0. Source
Strawberry Cervix
The organisms cause intense inflammationThe immune response creates tiny areas of bleeding (petechiae) on the cervix, making it look like a strawberry. → punctate hemorrhages on the cervix. Looks like someone flicked red paint at it.
Why TREAT THE PARTNER?
Because it's sexually transmitted. If only one person is treated, they get reinfected immediately. Men are often asymptomatic carriers.🔑If you don't treat the partner, he just keeps coming... back.
Same Drug, Different Reason
Metronidazole also kills Trich because it's activated in anaerobic/microaerophilic organisms. Trich happens to be one. But you MUST also treat the partner — that's the key difference from BV.
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NOT an STI
🍄
Candidiasis
Candida albicans
Weapon Thick, white, cottage cheese
pH
Key Symptom INTENSE ITCHING 🔥
Treatment Fluconazole
🔎 PSEUDOHYPHAE + BUDDING YEAST
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Why Candida Is the Odd One Out
It's a Fungus
Not bacteria, not a protozoan — yeast. It's already in the vagina normally. It only causes problems when something lets it overgrow.
THE Key Differentiator
pH is NORMAL (< 4.5). This is the single biggest board distinguisher. If pH is elevated, it's NOT candida. If pH is normal, it IS candida.
Why KOH Prep?
KOH (potassium hydroxide) lysesDissolves human cells and bacteria, leaving only the tough fungal cell walls. It's basically clearing the slide so only fungi remain visible. everything except fungi. So you add KOH to the slide and the pseudohyphae (branching filaments) stand out clearly.
Candida albicans with pseudohyphae on microscopy
See the branching filaments? Those are pseudohyphae — Candida's signature under the scope. Candida with pseudohyphae. Microrao, CC BY-SA 4.0. Source
Why Fluconazole (Not Metro)?
Metro kills anaerobes. Candida is a fungus. You need an azole — it blocks ergosterolA lipid in fungal cell membranes (like cholesterol in human cells). Block it and the fungal membrane falls apart. synthesis, destroying the fungal cell membrane.
Risk Factors (Board Loves These)
Antibiotics (kill protective bacteria), diabetes (glucose feeds yeast), pregnancy, immunosuppression (HIV, steroids). All let Candida overgrow.
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Section 2

Solve the Case

Click through the decision tree. This is exactly how you'd think on test day.

👩‍⚕️ Patient presents with vaginal discharge

First question: what's the pH?

↓
pH > 4.5
Elevated — something disrupted normal flora
pH < 4.5
Normal — flora is intact
🍄 Candidiasis
pH is elevated. What do you see on wet mount?
Clue Cells
Epithelial cells coated with bacteria, stippled edges
Motile Organisms
Pear-shaped, flagellated, darting around
🦠 Bacterial Vaginosis
🦠 Trichomoniasis
BVTrichCandida
OrganismGardnerellaT. vaginalisC. albicans
TypeBacteria (overgrowth)Protozoan (parasite)Fungus (yeast)
DischargeThin, gray, fishyGreen, frothyThick, white, cottage cheese
pH> 4.5> 4.5< 4.5 (normal)
MicroscopyClue cellsMotile trichomonadsPseudohyphae
Whiff TestPositiveCan be +Negative
STI?NoYESNo
TreatmentMetronidazoleMetro + partnerFluconazole
Key SymptomFishy smellStrawberry cervixITCHING

Section 3

4 Patients Just Walked In

Don't kill them. Get all 4 right and something fun happens.

Don't Fall For These

⚠️
Trap #1: Same Drug, Different Rules
Both BV and Trich use metronidazole. But only Trich requires partner treatment. If you see "treated with metro, returns with symptoms" — think untreated partner = Trich.
⚠️
Trap #2: Clue Cells ≠ Trichomonads
Clue cells are epithelial cells coated with bacteria (they don't move). Trichomonads are separate organisms that swim. If it moves, it's Trich. If it's stuck to a cell, it's BV.
⚠️
Trap #3: pH Is the Fastest Differentiator
Normal pH (< 4.5) = Candida. Period. Don't even think about BV or Trich if pH is normal. This alone eliminates one-third of the differential.🔑4.5 is the bouncer's number. Under = undisturbed. Over = overgrowth.
⚠️
Trap #4: Antibiotics CAUSE Candida
If a question says "patient was on antibiotics, now has vaginal itching + white discharge" — that's candida. The antibiotics killed protective bacteria, letting yeast overgrow. Don't pick BV.

Bone Wizardry — Reproductive