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Plate 6-26 Infectious Diseases

TOXIC SHOCK SYNDROME
Etiology and pathogenesis

STAPHYLOCOCCUS AUREUS
SKIN INFECTIONS (Continued)
Often associated with
superabsorbent tampon use
Cellulitis develops from a bacterial infection within
the dermis or the subcutaneous fat of the skin. The most Staphylococcal exotoxins (TSS1),
frequent location is on the lower extremities. It occurs enterotoxins (A,B,C)
more commonly in people with diabetes, trauma to the
skin, poor vascular circulation, or immunosuppression.
Cellulitis starts as a small, pink-to-red macule that
slowly expands and can encompass large portions of the Vaginal colonization by Staphylococcus
skin. This is associated with edema and pain. The condi- aureus with exotoxin production
tion is almost always unilateral. The pain can be severe.
Tender adenopathy of regional lymph nodes is present.
Fever and systemic symptoms are almost always present. Conditions required for Early phase manifests with
The redness is able to travel many centimeters a day. development of toxic flu-like symptoms, fever,
The presence of red lines is more indicative of a lymph- shock syndrome: rash, and hypotension
1. Bacterial colonization
adenitis than a cellulitis, but these conditions can 2. Exotoxin production
coexist. Erysipelas is a more superficial form of cellulitis 3. Entry portal for toxin
that occurs in the upper dermis. It manifests clinically
as a well-demarcated, edematous red macule that is
tender to the touch. The lower extremities and the face Clinical features of toxic shock syndrome
are common areas of involvement.
Toxic shock syndrome (TSS) is the name given to the Spectrum of disease ranges Fever greater Diffuse, macular General measures of
development of fever, hypotension, and near- from mild, flu-like symptoms than 39 C erythematous rash— organ support and shock
appearance similar
therapy should be instituted.
to rapid loss of function
erythroderma. The rash can appear as widespread, red, in various organ systems to “sunburn”
blanching macules. If appropriately treated, the rash Headache, irritability, and confusion
causes desquamation of the skin and return to normal
within a few weeks. TSS was initially reported after the Adult respiratory distress syndrome may complicate condition
use of superabsorbent tampons, which were left in place Hypotension (may be severe)
for the entire menstrual cycle. These tampons are no
longer available. The superabsorbent tampons provided Nausea and vomiting
an environment conducive to the rapid growth of S. Diarrhea
aureus. Toxins produced by the bacteria are responsible
for the symptoms. TSS can occur after any S. aureus
infection but is much more likely with an abscess. The
toxins act as superantigens and activate T cells without
the normal immune system processing. This can lead
to massive activation of the immune system.
Pathogenesis: S. aureus is a gram-positive bacteria
that is found throughout the environment and can be a
colonizer of humans. It is most likely to be found colo-
nizing the nares, the toe web spaces, and the umbilicus.
The bacteria grows in grape-like clusters on blood agar
cultures. S. aureus is one of the most common bacterial
causes of human infection.
Histology: The histological findings are based on the
form of infection biopsied. The common underlying
theme is a neutrophilic infiltrate that can be present
throughout the biopsy specimen. Bacteria are present
and can be highlighted on tissue Gram staining. The
inflammation in impetigo is often limited to the epider- Complete blood Desquamation Culture for Tampon
removal
mis, with bacteria and neutrophils present within the count, liver and of palms and Staphylococcus (remove
stratum corneum. Superficial blistering may occur renal function soles (occurs late) aureus nidus of
within the granular cell layer in bullous impetigo. Fol- studies infection)
liculitis shows edema and a neutrophilic infiltrate in and
around the hair follicle. Furuncles, carbuncles, and
abscess show a massive dermal infiltrate with neutro-
phils and bacterial debris. Mupirocin is one such topical agent that is highly Severe cases of cellulitis and all cases of TSS should
The pathology of cellulitis is more subtle, with neu- effective. The other forms of infection need to be be treated in the hospital in the appropriate setting.
trophils around blood vessels. Bacteria can be difficult treated with oral antibiotics. Cephalexin or dicloxacillin Intravenous antibiotics are always used, and vancomy-
to see or to culture from skin biopsies of cellulitis. Most is a good first choice. In areas with high rates of cin is the initial choice until the strain of S. aureus is
cases of cellulitis are not biopsied. TSS shows a super- community-acquired MRSA, one should consider cov- isolated and sensitivities are assessed. Once the sensi-
ficial and deep mixed inflammatory infiltrate. No bac- ering for this agent with a sulfa-based medication or a tivities of the bacteria have been determined, the anti-
teria are seen, because the rash is toxin mediated. tetracycline derivative in adults. Culturing of the bacte- biotic treatment can be tailored to the individual
Treatment: Impetigo can be treated with topical rial agent should be done in all cases to select the most patient. Patients with TSS often require intensive care
therapy against S. aureus and streptococcal species. effective medication. with pressure support and respiratory support.

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