Page 176 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 6-1 Integumentary System

ACTINOMYCOSIS

Many species of the bacterial genus Actinomyces are able
to cause disease in humans. The infection tends to run
a chronic course that leads to suppurative granuloma-
tous abscesses in the skin. The diagnosis may be sus-
pected if there is clinical evidence of painful draining
of suppurative material and histological evidence of
granuloma formation. The exact diagnosis is based on
tissue culture or culture of the suppurative material.
The disease is progressive if appropriate therapy is not
instituted. The organisms responsible for these infec-
tions are normally found within the oral cavity and are
commensal organisms. They can also be found through-
out the gastrointestinal tract.
Clinical Findings: Males are much more likely to
develop this infection than females, with an estimated
ratio of 3 : 1. Most patients are between 30 and 50 years
of age. Predisposing factors include poor dental hygiene.
The infection is believed to be endogenous in origin. It
is a rare infection in the United States. There are several
clinical pictures of actinomycosis. The most common
form seen is the cervicofacial subtype, which accounts
for more than 50% of cases. It is related to oral trauma, Cervicofacial subtype
such as recent dental work. The area that has been of actinomycosis
traumatized provides a portal of entry for the bacteria, (”lumpy jaw”)
and there is a progressive induration of the underlying
tissue. With time, the firm swelling begins to break
through the skin and to drain through multiple cutane-
ous fistulas. Pain can be intense and is relieved as the
fistulas spontaneously drain. The designation “lumpy
jaw” signifies the induration and fistula formation seen Abscess of chest wall
in patients with actinomycosis cervicofacial disease. and draining sinuses
The next most prevalent form of the disease is the due to actinomycosis.
pulmonary form. This is believed to be caused by aspi- The fungus spreads
ration of the causative bacteria. Patients often complain to the skin by direct
of hemoptysis and low-grade fever. Chest radiographs extension from the
can show features similar to those of tuberculosis infec- involved lung.
tions. Any lobe of the lung may be involved, but the
right lower lobe is most frequently affected because the
infection is caused by aspiration. If the disease goes
unrecognized, sinus tracts eventually form through the
lung lining, muscle, and skin to the thoracic cutaneous
wall. Skin abscess and a draining sinus in this location The “ray fungus” as it appears in H&E-stained
should lead one to look for pulmonary involvement, tissue section with surrounding neutrophilic
including the development of empyema. Abdominal infiltrate
forms of the disease are believed to occur after trauma
to the bowel. This has been reported most frequently
after appendectomy, and for unknown reasons the bac-
teria localize to that area. The last form of the disease
is the disseminated form, which is rare and can occur
after any form of the disease that is not appropriately
treated. Any organ system may be involved. Pus in a Petri dish showing two
Histology: Biopsy specimens show a suppurative sulfur granules (small lumps
granulomatous reaction pattern. Neutrophils, histio- indicated by arrows)
cytes, and lymphocytes make up the majority of the
inflammatory infiltrate. Basophilic granules (sulfur
granules) are surrounded by a predominantly neutro-
philic infiltrate.
Anaerobic culture of the purulent material or a
portion of the tissue is critical for proper identification
of the responsible organism and ultimately for choosing
the appropriate therapy. Material should be sent anaero-
bically immediately to the laboratory. Yellow to white A. meyeri, A. naeslundii, A. radingae, A. europaeus, A. Treatment: The drug of choice to treat this bacterial
sulfur granules form as the culture material grows. Eval- viscosus, A. neuii, or A. odontolyticus. A. israelii is the infection is penicillin. Therapy needs to be maintained
uation of the sulfur granules with the use of an oil organism most frequently observed to cause disease. for months to be certain of complete cure. If the infec-
immersion microscope shows the filamentous bacteria. These are anaerobic, acid-fast bacteria that have a fila- tion is treated promptly, almost all patients have a full
Pathogenesis: Actinomycosis is caused by one of the mentous morphology with varying amounts of branch- and complete recovery. Patients who are allergic to
gram-positive filamentous bacteria of the Actinomyces ing. The definitive diagnosis is made by culture of the penicillin can be treated with any of the tetracycline-
genus: A. israelii, A. turicensis, A. lingnae, A. gravenitzii, organism. based antibiotics.

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