NeuroLearn NeuroHelp Bacteria @ General information Clinical stages Syphilis and HIV infection CSF Pathology
General information:
Geographic
distribution:
Port
of entry:
Congenital
infection:
Number
of stages:
Primary
syphilis:
Local dermatological manifestation (primary chancre) not associated with
clinical neurological sighs and symptoms. Self-limiting in most cases.
Secondary
syphilis: Acute
dissemination phase with maculopapular, vesicular and even bullous lesion of
the skin and mucous membranes. This stage is highly contagious. This phase
occurs several weeks or months after primary chancre. About 10% of the
untreated case will go on to develop late (tertiary) syphilis.
Tertiary
syphilis:
This stage involves maninly the CNS (neurosyphilis).
Asymptomatic
CNS involvement
can occur in all untreated cases in any phase of the disease.
Culture:
T. pallidum is present in 30% of
untreated primary and secondary syphilis.
Pathology:
General consideration:
Head
Involvement
of the CNS in syphilis is not limited to the tertiary phase.
Damage
of the brain can be caused by direct inflammatory changes, ischemic insults
due to vascular inflammation, and progressive neuronal destruction unrelated
to the ischemic insults (tabes dorsalis and general paresis).
Syphilitic
meningitis:
Head
General:
Peak incidence 1-2 years after infection; often with cranial nerve
involvement (most common in CN VII, VIII followed by II, III, VI, and then
by V). This is the least common neurosyphilitic manifestation.
Meningovascular
syphilis:
Head
General:
Peak incidence 5-7 years after infection; usually presents as focal
neurologic deficits secondary to comprised cerebral circulation. Can be seen
in about 10% of cases diagnosed with CNS involvement.
Gross:
Diffuse
or localized to the base of the brain. Hydrocephalus secondary to meningeal
fibrosis is frequent.
Histology:
Perivascular lymphoplasmocytic infiltration around small blood vessels in
the thickened meninges (periarteritis). Involvement of cranial nerves
(particularly CN II and causes optic nerve atrophy) and spinal nerves are
common. Heubner’s arteritis consists
of crescentic enarteritis obliterans and corresponding thining of the media.
The elastic lamina remains intact. Vasa vasorum are cuffed by
lymphoplasmocytic cells.
Parenchymatous
neurosyphilis (paralytic dementia and tabes dorsalis): Head
General:
Peak incidence 10-20 years after infection. They progressive and irreversible.
Paralytic dementia
Gross:
Gross findings in advanced cases are characteristic and consist of a
shrunken and firm brain covered by a remarkably thick and opaque
pia-arachnoid meninges. The frontal areas are most affected. Ventricles are
very dilated and the ependyma has a fine ground-glass appearance due to
extensive granular ependymitis.
Histology: Scattered foci of neuronal loss and gliosis of different ages giving a bush fire appearance. Striking microglial proliferation and microglial cells are hypertrophied and elongated and impregnated with iron (rod cells) that is well demonstrated by special stain. Vascular inflammation with lymphoplasmocytic infiltration in the meninges and cortex.
Gross:
Selective degeneration of the dorsal nerve roots, dorsal root ganglia and
dorsal column of the spinal cord. The cord shows a typical reduction of
ventrodorsal dimension.
Histology:
Secondary wallerian degeneration and demyelination in the dorsal column.
Meningeal thickening and a variable amount of inflammatory cells. Unlike
paralytic dementia, there is no inflammatory reaction in the cord parenchyma
and T. pallidum is absent.
General:
Relatively rare. Can occur at any time and at any location of the CNS. Clinical
manifestations are due to mass effect and location irritation of the gumma.
Gross:
Most common in the cerebral convexity. They are usually embedded in the
brain with attachment to the dura. Some of them are confined to the dura.
Histology:
Central gummatous necrosis with ghost –like outlines of dead cells and
surrounded by multiple, densely cellular epithelilid cells and fibroblasts
with scattered multinucleated giant cells of the foreign body type.
Spirochetes are often not found.