Hutchinson triad

**Components of the triad** 1. **Interstitial keratitis**: Inflammation of the corneal stroma causing photophobia, pain, and corneal clouding/vascularization ("salmon patch"). It is thought to be an immune-mediated (hypersensitivity) response rather than direct invasion. It usually appears between ages 5 and 20. 2. **Sensorineural hearing loss (CN VIII involvement)**: Caused by labyrinthitis or damage to the eighth cranial nerve. It is typically bilateral, progressive, and appears in later childhood or adolescence. 3. **Hutchinson teeth**: Permanent upper central incisors that are peg-shaped, widely spaced, and notched on the biting edge. Damage to the tooth germ during development causes this. Related finding: "mulberry molars" (Moon molars), which are abnormal first molars.

**Pathophysiology** - *Treponema pallidum* (a spirochete) crosses the placenta, usually after the first trimester (about 16–18 weeks or later). Risk is highest with maternal primary or secondary syphilis. - **Early congenital syphilis (<2 years)** includes snuffles (rhinitis), maculopapular rash on palms and soles, condylomata lata, hepatosplenomegaly, lymphadenopathy, osteochondritis/periostitis (pseudoparalysis of Parrot), pneumonia alba, and hemolytic anemia. - **Late congenital syphilis (>2 years)** includes Hutchinson triad, saber shins (anterior tibial bowing), saddle nose, frontal bossing, higher palate, Clutton joints (painless bilateral knee effusions), and rhagades (perioral fissures).

**Diagnosis** - Nontreponemal tests (RPR/VDRL) are used for screening and for monitoring treatment response. Treponemal tests (FTA-ABS, TP-PA) confirm the diagnosis. - Darkfield microscopy or PCR can be done on lesions or fluid. - Maternal screening occurs at the first prenatal visit, with repeat testing in the third trimester and at delivery in high-risk women.

**Treatment and prevention** - **Penicillin G** is the drug of choice. It is the only acceptable treatment in pregnancy, so penicillin-allergic pregnant women must be desensitized. - Treating the mother at least 30 days before delivery prevents congenital infection. - Neonates with proven or probable disease get IV aqueous penicillin G for 10 days. - Jarisch–Herxheimer reaction (fever, myalgias, and hypotension from cytokine release after spirochete death) may occur after starting treatment.

**High-yield pearls** - Don't confuse it with **Charcot triad** (cholangitis: fever, jaundice, RUQ pain), **Cushing triad** (hypertension, bradycardia, irregular respirations), or **Beck triad** (tamponade). - Hutchinson teeth are a **late** finding. The notched incisors are not present at birth because permanent teeth erupt later. - Interstitial keratitis can also occur in Cogan syndrome (with vestibuloauditory symptoms) and with TB, but the triad is specific to congenital syphilis. - The eponym is also used for **Hutchinson sign** in herpes zoster ophthalmicus (a vesicle on the tip of the nose, which indicates nasociliary branch of V1 involvement and a high risk of ocular involvement). It is a separate concept, and the same physician, Jonathan Hutchinson, is credited with both.