spirochete, (order Spirochaetales), also spelled spirochaete, any of a group of spiral-shaped bacteria, some of which are serious pathogens for humans, causing diseases such as syphilis, yaws, Lyme disease, and relapsing fever. Examples of genera of spirochetes include Spirochaeta, Treponema, Borrelia, and Leptospira.
Spirochetes are gram-negative, motile, spiral bacteria, from 3 to 500 m (1 m = 0.001 mm) long. Spirochetes are unique in that they have endocellular flagella (axial fibrils, or axial filaments), which number between 2 and more than 100 per organism, depending upon the species. Each axial fibril attaches at an opposite end and winds around the cell body, which is enclosed by an envelope. Spirochetes are characteristically found in a liquid environment (e.g., mud and water, blood and lymph).
yaws
yaws
Treponema includes the agents of syphilis (T. pallidum pallidum) and yaws (T. pallidum pertenue). Borrelia includes several species transmitted by lice and ticks and causing relapsing fever (B. recurrentis and others) and Lyme disease (B. burgdorferi) in humans. Spirochaeta are free-living nonpathogenic inhabitants of mud and water, typically thriving in anaerobic (oxygen-deprived) environments. Leptospirosis, caused by Leptospira, is principally a disease of domestic and wild mammals and is a secondary infection of humans.
6. Two conditions which are more likely to be
encountered with orthopaedics are: syphilis
and yaws
7. SYPHILIS
generally acquired during sexual activity by direct contact with infectious
lesions of the skin or mucous membranes. The infection spreads to the
regional lymph nodes and then to the bloodstream.
CONGENITAL AND ACQUIRED SYPHILIS
The organism can cross the placental barrier and enter the fetal blood stream
directly during the latter half of pragnancy, giving rise to congenital syphilis.
ln congenital syphilis, the primary infection may be so severe that the fetus is
either stillborn or the infant dies shortly after birth.
8. Clinical features of congenital syphilis
Infection is present at birth, bone changes do not usually appear until several
weeks afterwards
Examination may show skin lesions, hepatosplenomegaly and anaemia.
The first signs of skeletal involvement may be joint Swelling and
'pseudoparalysis' - the child refuses to move a painful limb.
The characteristic X-ray changes are of two kinds-
1. osteochondritis ("metaphysitis") - trabecular erosion in the juxta-epiphyseal
regions of tubular bones showing first as a lucent band near the physis and later
as frank bone destruction which may result in epiphyseal separation.
2. diffuse periosteal new bone formation along the diaphysis, usually of mild
degree but sometimes producing an 'onion-peel' effect.
9. Late congenital syphilis
• 10 or 15 years after birth may be manifestations of tertiary disease, the
result of gumma formation and endarteritis.
• Sometimes the predominant feature is dense endosteal and periosteal
new bone formation affecting almost the entire bone (the classic 'sabre
tibia’).
Other abnormalities-
1.dental malformations (Hutchinson's teeth’)
2.finger phalanges (dactylitis)
3.painless effusions in the knees or elbows ('Clutton's joints')
12. Wimberger's sign, also
called Wimberger's corner
sign, refers to localized
bilateral metaphyseal
destruction of the medial
proximal tibia. It is a
pathognomonic sign for
congenital syphilis."
13. Saber shins -the tibial bone has a pronounced anterior bowing
(i.e., bends forward), so the shape of the lower leg resembles a
saber, a sword with a curved blade.
15. acquired syphilis-
A primary ulcerous lesion, or chancre, appears at the site of inoculation about a
month after initial infection. It usually heals without treatment but, a month or
more after that, the disease enters a secondary phase characterized by the
appearance of a maculopapular rash and bone and joint changes due to
periostitis, Osteitis and osteochondritis.
After a variable length of time, this phase is followed by a latent period which may
continue for many years.
About half the cases pathological lesions continue to appear in various organs and
10-30 years later the patient may present again With tertiary syphilis, which takes
various forms including the appearance of large granulomatous gummata in bones
and Joints and neuropathic disorders in which the loss of sensibilities gives rise to
joint breakdown (Charcot jotnts).
16. Clinical features of acquired syphilis
Early features
pain, swelling and tenderness of the bones, especially of the frontal bones of
the skull, the anterior surface of the tibia, the sternum and the ribs.
X-rays may show typical features of periostitis and thicken bones . Osteitis and
septic arthritis are less Common.
Enquiry may reveal a history of sexually transmitted disease.
Late features
appear only after many years, is the syphilitic gumma, a dense granulomatous
lesion associated with local bone resorption and adjacent areas of sclerosis.
Sometimes this results in a pathological fracture.
X-rays may show thick periosteal new bone formation at other sites, especially
the tibia.
17. tertiary syphilis
a neuropathic arthropathy due to loss of sensibility in the joint most
characteristically the knee.
Other neurological disorders- are tabes dorsalis and 'general paralysis of the
insane' (GPI).
With modern treatment, these late sequelae have become rare.
(TABES DORSALIS- slow degeneration of the nerve cells and
nerve fibers that carry sensory information to the brain.)
22. Treatment
Early lesions-
intramuscular injections of benzylpenicillin given weekly for 3 or 4 doses
Late lesions-
require high-dosage intravenous penicillin for a week or 10 days, but some
forms of tertiary syphilis will not respond at all. An alternative would be
treatment with one of the third generation cephalosporins.
23. YAWS
A non-venereal spirochaetal infection
caused by Treponema pertenue. It is
seen mainly in the poorer tropical parts
of Africa, Asia and South America.
infection by skin-to-skin contact.
A knobby ulcer covered by a scab (the
primary or mother yaw), usually
develops on the face, hands or feet.
24. •Secondary skin lesions appear -4 months later and
successive lesions may go on to pustular ulceration;
as each one heals it leaves a pale tell-tale scar.
• secondary stage is followed by a long latent period, merging
into a tertiary stage during which skeletal changes similar to
those of syphilis develop periosteal new bone formation,
cortical destruction and osteochondritis.
25. Clinical features
•Children under 10 years old are the usual victims
•Skin lesions and an associated lymphadenopathy
• Further investigations may be called for -serological
tests and dark field examination of scrapings from
one of the skin lesions.
•Later stage deformities and bone tenderness may
become apparent.
26. X RAY FEATURES-
cortical erosion, joint destruction and periosteal
new bone formation; occasionally thickening of a
long bone may be so marked as to resemble the
'sabre tibia’ of late congenital syphilis.
27. Treatment
benzylpenicillin, preferably given by intramuscular
injection, is effective. For those who are
hypersensitive to penicillin, erythromycin is a
satisfactory alternative.