GROUP A STREPT INFECTIONS
STREPT PYOGENES (Group A Strept) INFECTIONS
1) Pharyngitis/Tonsillitis
2) Scarlet Fever
3) Erysipelas
4) Necrotising fasciitis/myositis
5) Toxic Shock Syndrome
IMMUNE COMPLICATIONS OF STREPT PYOGENES INFECTION:
1) Rheumatic fever
2) Glomerulonephritis
3) Erythema nodosum
1) PHARYNGITIS/TONSILLITIS
Commonest cause in all comers:
VIRAL
Age 3-13yrs: 30-40% BACTERIAL
Complications of Strept pyogenes pharyngitis = rare in non-indigenous populations
Eg: Rheumatic fever < 1 case per 100,000
cf risk of severe reaction to Penicillin = 15 to 40 per 100,000 treatment courses
 ABx not really indicated outside of INDICATIONS below
Benefits of ABx:
90% of placebo & ABx groups free of Syx in 1 week
ABx treated = 8 hours less Syx! (& more adverse effects)
INDCIATIONS FOR ABx: (penicillin bd or roxithromycin if allergic)
1) Tonsillitis + 4 diagnostic features of Strept pyogenes:
a. T > 38 deg
b. Tender cervical lymphadenopathy
c. Tonsillar exudate
d. No cough
2) Age 2-25yo in high risk communities (eg Indigenous/underprivileged)
3) Existing Rheumatic heart disease
4) Scarlet Fever
5) Quinsy
2) SCARLET FEVER
Dx: Classic Syx/Signs
Circumoral pallor
Sandpaper rash (which subsequently desquamates, can last 1 week)
Strawberry tongue
Spots/macules on palate & uvula (Forchheimer spots)
Along with: fever, sore throat, lymphadenopathy, abdo pain
POTENTIAL SEPTIC COMPLICATIONS = rare
Otitis, pneumonia/empyema, meningitis, septicaemia
POTENTIAL IMMUNE COMPLICATIONS – as above
TREATMENT: Penicillin/roxicthromycin/clarithromycin
3) ERYSIPELAS
More superficial than cellulitis
(Distinction between Erysipelas and cellulitis: subtle & clinically irrelevant)
Common sites: Face, Lower legs
May be underlying Sinus or Dental Infection: must examine teeth & consider sinus
imaging
More common in young & elderly
Pathogens: Grp A Strept, Staph spp, Haemophilus
Uni or Bilateral, sharply demarcated erythema, vesicles/bullae may be present
If unilateral: consider: Zoster
If bilateral: consider: SLE, contact dermatitis
Caution: Periorbital/orbital cellulitis
Treatment: Di/Flucloxacillin, Penicillin (if Strept confirmed), if allergic:
Cephalosporin or Clindamycin
4) NECROTISING FASCIITIS
NB: Don’t confuse “Gas” in tissues with GrpAStrep (which has NO GAS in tissue!)
GAS GANGRENE (Myonecrosis): = MUSCLE involved, Gas in tissues
1) Clostridial Myonecrosis: more common
2) Non-Clostridial Myonecrosis (polymicrobial)
3) Streptococcal myositis: rare, no gas, high mortality (80-100%)
NECROTISING FASCIITIS: soft tissue/fascia only = NO MUSCLE
1) Polymicrobial Infection: more common, may get crepitus (gas) late sign
2) Grp A Strept Infection: NO crepitus (gas)
Grp A Strept Necrotising Fasciitis: Invasive Grp A Strept infection:
Mortality: 20-60%
Risk  by: Concurrent Varicella (portal of entry) & NSAID use
Predisposed: Diabetic, PVD, Malignancy, IVDU, alcoholic, immunosuppressed
Increased mortality: Elderly, age < 1, CRF, CCF, cancer, trunk involved, perineum,
delayed Dx
Spreading caused by: bacterial toxins & vascular inflammation/thrombosis/ischaemia
Clinical: PAIN OUT OF PROPORTION TO PHYSICAL FINDINGS
Treatment:
1) Resusc (avoid pressors  worsens ischaemia)
2) Antibiotics
3) Surgery = MAINSTAY OF TREATMENT
4) Immediate postop hyperbaric (only useful for ANAEROBIC component ie
not much use in GrpAStrept)
ANTIBIOTICS:
Empiric: MEROPENEM + CLINDAMYCIN
Grp A Strept: PENICILLIN/Ceph + CLINDAMYCIN + Ig
Polymicrobial: MEROPENEM
Clostridium: PENICILLIN (Metronidazole if allergic)
5) STREPTOCOCCAL TOXIC SHOCK SYNDROME (STSS)
NB: Different to tampon related TSS (Staph) (Menstrual Related TSS: MRTSS).
NB: Nasal packing can also lead to Staph TSS. Also: Body piercing!
STSS: MORE SERIOUS THAN Staph TSS: = “Flesh Eating Bacteria”
End of spectrum of Grp A Strept infections (ie most severe)
50% Start as Necrotising Fasciitis, Rare to start from pharyngitis
Mortality: 30-70%, worse if muscles involved,
Definition:
Invasive GrpAStrept SOFT TISSUE infection
Early onset (<48hrs) of Shock
Multi-organ involvement:
Renal, Liver, ARDS, Coagulopathy
Skin: erythroderma, desquamation, nec fasc, myositis, gangrene
Caused by virulent EXOTOXINS, so called “superantigens”
Portal of entry not identified in 50%, may be Skin, vagina, pharynx, mucosa, nonpenetrating muscle injuries
NB: May get abdo/pelvic pain, chest pain if source is there
Treatment: Resusc, ABx, Surgery, +/- IV Immunoglobulin
NB Staph & Strept TSS
COMMON SYX:
VOMITING & DIARRHOEA: profuse, seen in 90-98%!
ERYTHRODERMA: diffuse, blanching, “painless sunburn”
MYALGIA/ARTHRALGIA
DELERIUM
RHEUMATIC FEVER = AUTOIMMUNE CONDITION
Can occur after ANY Strept pyogenes (Grp A Strept) infection
BUT:
Most common after:
1) Pharyngitis/Tonsillitis
2) Scarlet Fever
(ie you tend to die from the more serious ones, if you survive Rheumatic fever is the
least of your worries)
Usually starts about 3 weeks after initial Strept infection
Commonest Age: 5-15 yrs
Rare but serious: mortality 2-5%
Pathophysiology:
Cross reaction of anti-Strept Ab with cardiac and arterial smooth muscle
Up to 30% may have no symptoms of initial Strept infection
Rate of progression of untreated Strept infection  Rheumatic fever
3% (wikipedia)
1 in 100,000 (ABx guidelines)
Initial episode of Rheumatic fever predisposes to “flare-ups” or recurrence (up to
50%) with subsequent Strept infections  lifelong ABx usually prescribed
DIAGNOSIS:
JONES CRITERIA
2 major criteria or 1 major & 2 minor criteria
Major criteria
J: Joints: migratory polyarthritis
O: (heart shaped “O”): Carditis: CCF, pericarditis (“bread & butter), pancarditis,
murmur (valve damage: thickening, verrucae, commissural fusion)
N: Nodules: subcutaneous nodules (Aschoff bodies): wrist, elbow, knees
E: Erythema marginatum: macular rash on trunk
S: Sydenham’s chorea (St Vitus’ dance) = very late
Minor Criteria
Fever
Arthralgia (without swelling)
Raised ESR/CRP
ECG abnormalities (eg long PR)
Evidence of Grp A strept (ASO titre, or DNAase):
NB by the time Rh fever starts CULTURES will be NEGATIVE
Previous rheumatic fever or inactive Rh heart disease
TREATMENT:
Steroids
Aspirin
Lifelong ABx (penicillin)
2) GLOMERULONEPHRITIS
Probably not going to diagnose in ED
3) ERYTHEMA NODOSUM
Immune mediated inflammation of fat cells under skin = “Panniculitis”
Tender red nodules on shins, (also thighs, trunk, arms, face), 1-5cm diameter
Can coalesce, look like resolving bruises
Usually subside over 2-6 weeks
DDx: Ringworm
Other causes:
Idiopathic (30-60%)
Infections: Grp A Strept, TB, Mycoplasma, EBV,
Inflam: Sarcoid, IBD, Behcet’s
Pregnancy
Medication: OCP, sulfonamides
Malignancy
Treatment:
Treat cause
Rest, elevation, NSAIDS
Steroids in severe/refractory
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