# Necrotising Fasciitis and Toxic Shock in Obstetrics

> NEET-PG Obstetrics and Gynaecology notes on necrotising fasciitis and obstetric toxic shock: streptococcal infection, early recognition and debridement.

- Canonical URL: https://prepelephant.com/topics/neet-pg/obstetrics-and-gynaecology/necrotising-fasciitis-and-toxic-shock-in-obstetrics
- Exam / course: NEET-PG · Subject: Obstetrics and Gynaecology
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-08
- Last updated: 2026-10-08
- Reference basis: Williams Obstetrics; Harrison's Principles of Internal Medicine; Bailey and Love's Short Practice of Surgery
- How to cite: "Necrotising Fasciitis and Toxic Shock in Obstetrics", PrepElephant, https://prepelephant.com/topics/neet-pg/obstetrics-and-gynaecology/necrotising-fasciitis-and-toxic-shock-in-obstetrics

## Direct answer

Necrotising fasciitis is a rapidly spreading infection of fascia and subcutaneous tissue, most often group A streptococcal, after caesarean or perineal wounds. Its earliest feature is pain out of proportion to visible skin signs, followed by rapid spread, skin discolouration, bullae and systemic toxicity. Toxic shock is the toxin-mediated systemic complication, with hypotension and multi-organ failure. Early surgical debridement with broad-spectrum antibiotics, including clindamycin, is the cornerstone of treatment.

## What you must remember

- **Organism:** group A streptococcus (Streptococcus pyogenes) is the classic cause in obstetric wounds; other infections are often polymicrobial.
- **Early clue:** severe pain out of proportion to skin changes, with spreading erythema and oedema.
- **Late signs:** skin necrosis, bullae, crepitus from gas, dusky skin and septic shock.
- **Toxic shock features:** fever, hypotension, diffuse rash, later desquamation, and involvement of at least three organ systems.
- **Staphylococcal toxic shock:** Staphylococcus aureus toxin (TSST-1) causes the menstrual-type syndrome, classically linked to retained tampons or products.
- **Management:** early surgical debridement to healthy tissue, IV broad-spectrum antibiotics with clindamycin for toxin suppression, and resuscitation.
- **Adjunct:** intravenous immunoglobulin may be considered in streptococcal toxic shock per specialist advice.

## Pain after an episiotomy repair

A woman has fever and severe perineal pain 36 hours after an episiotomy repair, with spreading redness and a falling blood pressure. Her pain is out of proportion to the visible skin, which is the warning sign. The steps below follow the emergency pathway, where antibiotics and surgery proceed together.

1. **Suspect early:** pain out of proportion to visible skin changes warrants urgent surgical review, not waiting for skin signs.
2. **Resuscitate:** fluids, oxygen, blood cultures and lactate are taken, and empirical broad-spectrum antibiotics start at once.
3. **Add antitoxin cover:** clindamycin is added to suppress toxin production in streptococcal disease.
4. **Debride early:** wide excision of necrotic fascia and skin is performed and repeated as needed.
5. **Find the source:** the wound, uterine cavity and any retained products are examined and infected material removed.
6. **Support organs:** intensive care, renal support and monitoring for toxic shock continue until stable.

## Where the exam tries to catch you

These questions test early recognition, the role of surgery and the antitoxin choice.

- **Trap:** waiting for skin changes before surgical referral — **Correct:** severe pain out of proportion to signs is the earliest clue, so surgical review cannot wait.
- **Trap:** treating with antibiotics alone without debridement — **Correct:** necrotic tissue has poor blood supply, so antibiotics cannot clear it and debridement is essential.
- **Trap:** attributing obstetric toxic shock only to tampon use — **Correct:** in obstetrics, retained products, infected wounds and streptococcal infection are the usual sources.

## Frequently asked questions

### What is the earliest clinical sign of necrotising fasciitis?

The earliest clinical sign of necrotising fasciitis is pain out of proportion to the visible skin changes. Redness and oedema appear later, followed by discolouration, bullae and crepitus. Surgical review is needed as soon as this pain is noted.

### Which organism commonly causes necrotising fasciitis in obstetrics?

Group A streptococcus is the classic organism causing necrotising fasciitis in obstetric wounds, often after caesarean or perineal repair. Mixed infections can also occur. Staphylococcus aureus is more typically associated with menstrual-type toxic shock syndrome.

### What are the features of toxic shock syndrome?

Toxic shock syndrome features include fever, hypotension, a diffuse rash, desquamation during recovery and involvement of at least three organ systems. Recognition is clinical, since laboratory tests are non-specific. Prompt resuscitation and source control are essential.

### Why is clindamycin added in streptococcal toxic shock?

Clindamycin is added in streptococcal toxic shock because it suppresses bacterial toxin production, which beta-lactam antibiotics do not. It complements penicillin or another broad-spectrum agent. Surgical debridement remains essential alongside it.

### How is necrotising fasciitis after caesarean section treated?

Necrotising fasciitis after caesarean section is treated with urgent surgical debridement of necrotic tissue and broad-spectrum antibiotics covering streptococci and anaerobes. Resuscitation and organ support follow. Source control in the wound and uterus is also needed.