section name header

Information

Bone and Soft-Tissue Disorders

[syphlos, Greek = crippled]

= “The Great Imitator” of neoplastic / autoimmune conditions

Organism: spirochete Treponema pallidum = spiral-shaped extracellular microorganisms with internal flagella resulting in twisting locomotion; evades immune system through antigenic variation

Transmission: sexually / placentally

Congenital Syphilis!!navigator!!

  • Transplacental transmission cannot occur <16 weeks gestational age
  • positive rapid plasma reagin (measures quantity of antibodies to assess new infection / efficacy of Rx)
  • positive microhemagglutination test for Treponema pallidum (remains reactive for life)
  • pneumonia alba
  • hepatomegaly

Location: symmetrical bilateral osteomyelitis involving multiple bones (HALLMARK)

  1. Early phase
    ◊ Skeletal radiography abnormal in 19% of infected newborns without overt disease!
    1. Metaphysitis
      • lucent metaphyseal band adjacent to thin / widened zone of provisional calcification ← disturbance in enchondral bone growth
      • frayed edge of metaphyseal-physeal junction (osteochondritis) = erosions + lytic defects
    2. Diaphyseal periostitis = “luetic diaphysitis”
      • solid / lamellated periosteal new-bone growth = bone-within-bone appearance
    3. Spontaneous epiphyseal fractures causing Parrot pseudopalsy (DDx: battered child syndrome)
    4. Bone destruction
      • marginal destruction of spongiosa + cortex along side of shaft with widening of medullary canal (in short tubular bones)
      • patchy rarefaction in diaphysis
    5. Wimberger sign
      • symmetrical focal bone destruction of medial portion of proximal tibial metaphysis (ALMOST PATHOGNOMONIC)
  2. Late phase
    • Hutchinson triad = dental abnormality, interstitial keratitis, 8th nerve deafness
    • frontal bossing of Parrot = diffuse thickening of outer table
    • saddle nose + high palate (syphilitic chondritis + rhinitis)
    • short maxilla (maxillary osteitis)
    • thickening at sternal end of clavicle
    • “saber-shin” deformity = anteriorly convex bowing in upper ⅔ of tibia with bone thickening

Acquired Syphilis!!navigator!!

= TERTIARY SYPHILIS resembles chronic osteomyelitis

  • dense bone sclerosis of long bones
  • irregular periosteal proliferation + endosteal thickening with narrow medulla
  • extensive calvarial bone proliferation with mottled pattern (anterior half + lateral skull) in outer table (DDx: fibrous dysplasia, Paget disease)
  • ill-defined lytic destruction in skull, spine, long bones (= gumma formation)
  • enlargement of clavicle ← cortical + endosteal new bone
  • Charcot arthropathy of lower extremities + spine

Primary Syphilis

  • HALLMARK painless cutaneous ulcer (chancre)

Meningovascular Neurosyphilis

Cause: direct spirochete invasion of vascular endothelial cells → vasculitis

  • stroke in young adult (MCA >basilar artery territory)

Outline