8. Orbital Septum
• Thin membrane that originate from orbital
periosteum which insert into anterior surface
of tarsal plates of the eyelid.
• Anatomical landmark which separate
superficial eyelid from deeper orbital
structure.
**Fx: prevent infection in eyelid extending into
the orbit.
9. • Infection of soft tissue of
eyelid and periocular region
anterior to orbital septum.
• Pathophysiology
– Spread of URTI by venous &
lymphatic channels
– Direct inoculation from trauma
– Spread from skin & adjacent
structural infection
• Clinical features
– Periorbital erthema & oedema,
pain, conjunctivitis, epiphora
and blurred vision.
**if oedema severe enough
cannot open the eye
Pre-septal Cellulitis
10. • Infection of the orbital tissues
posterior to orbital septum.
• Pathophysiology
– Extension of infection from
periorbital structure especially
paranasal sinus
**Most common infection from
ethmoid sinus.
– Direct inoculation from
trauma/surgery
– Haematogenous spread
• Clinical features
– Fever, malaise, history of recent
sinusitis/URTI
– exophthalmos, partial/total vision
loss, conjunctiva chemosis, restrict
eye movement
– Headache, rhinorrhea
Orbital Cellulitis
11. • An abscess between the
periosteum and cortical
plate of the bone.
• Clinical features
-- eyelid edema/
erythema/ warmth,
conjunctival injection
with chemosis and
restricted ocular
motility with or without
diplopia.
Subperiosteal abscess
12. • Pus accumulation in the
orbital soft tissues behind
the globe
• Due to : extended infection
into the orbital fat
associated with
inflammatory edema,
purulence, and fat necrosis
• Features : Severe chemosis,
ptosis and complete
ophthalmoplegia (cranial
nerves II, III, IV, V, and VI)
and visual loss
Orbital Abscess
13. • The cavernous sinuses receive venous blood from
the facial as well as the sphenoid and middle
cerebral veins. They, in turn, empty into the inferior
petrosal sinuses, then into the internal jugular veins
and the sigmoid sinuses via the superior petrosal
sinuses.
• This complex web of veins contains no valves; blood
can flow in any direction depending on the
prevailing pressure gradients. Since the cavernous
sinuses receive blood via this distribution, infections
of the face including the nose, tonsils, and orbits
can spread easily by this route.
• This intimate juxtaposition of veins, arteries,
nerves, meninges, and paranasal sinuses accounts
for the characteristic etiology and presentation of
cavernous sinus thrombosis (CST).
• CST is more commonly seen with sphenoid and
ethmoid and to a lesser degree with frontal
sinusitis.
• Staphylococcus aureus accounts for approximately
70% of all infections.Streptococcus
pneumoniae, gram-negative bacilli, and anaerobes
can also be seen. Fungi are a less common
pathogen and may
include Aspergillus andRhizopus species.
Cavernous Sinus Thrombosis
16. • Meningitis is an inflammation of the
membranes (meninges) surrounding
your brain and spinal cord.
• Acute bacterial meningitis usually
occurs when bacteria enter the
bloodstream and migrate to the brain
and spinal cord. But it can also occur
when bacteria directly invade the
meninges, as a result of an ear or
sinus infection, or a skull fracture, or
rarely, after some surgeries.
• A number of strains of bacteria can
cause acute bacterial meningitis. The
most common include Streptococcus
pneumoniae (pneumococcus),
Neisseria meningitidis
(meningococcus), Haemophilus
influenzae (haemophilus), Listeria
monocytogenes (listeria).
Meningitis
17. • An epidural abscess is a
collection of pus between the
outer covering of the brain and
the bones of the skull
• Clinical Features : Fever,
headache, lethargy, nausea,
vomiting, pain at the site of
recent surgery that gets worse
• Neurological symptoms
depend on the location of the
abscess :
1. decreased ability to move
2. Loss of sensation
3. Weakness
Frontal sinusitis showing epidural abscess
Epidural Abscess
18. • Subdural abscess is an intracranial focal
collection of purulent material located between
the dura mater and the arachnoid mater.
• In infants and young children, subdural
empyema most often occurs as a complication
of meningitis. In such cases, subdural empyema
should be differentiated from reactive subdural
effusion (ie, sterile collection of fluid due to
increased efflux of intravascular fluids from
increased capillary wall fenestrations into the
subdural space).
• In older children and adults, it occurs as a
complication of paranasal sinusitis, otitis media,
or mastoiditis.
• Infection usually enters through the frontal or
ethmoid sinuses; less frequently, it enters
through the middle ear, mastoid cells, or
sphenoid sinus.
• This often occurs within 2 weeks of a sinusitis
episode, with the infection spreading
intracranially through thrombophlebitis in the
venous sinuses.
• Infection also may extend directly through the
cranium and dura from an erosion of the
posterior wall of the mastoid bone or frontal
sinus.
Subdural abscess
19. • A brain abscess is a pus-filled swelling in
the brain caused by an infection. It is a
rare and life threatening condition.
• Pathophysiology:
1. an infection in another part of the skull,
such as an ear infection, sinusitis or
dental abscess, spreads directly into the
brain
2. an infection in another part of the body,
such as the lung infection pneumonia,
spreads into the brain via the blood
3. trauma, such as a severe head injury,
that cracks open the skull allowing
bacteria or fungi to enter the brain
• Clinical features:
- Severe headache, changes in mental
status, weakness or paralysis on one side
of the body, fever , seizures
Intracerebral abscess
20. Sagittal (a) and axial (b) gadolinium-enhanced T1-weighted MRI images from a
patient who presented with headache, word-finding difficulties, stuttering
speech, and right hand/foot numbness. Note the peripheral enhancement of a
lesion in the left insula with surrounding edema.
21. • Cavernous sinus thrombosis is a rare and
life-threatening condition in which a blood
clot develops in the cavernous sinuses.
• Pathophysiology:
Most cases of cavernous sinus thrombosis
occur when a bacterial infection in
another part of the skull or face spreads
into the cavernous sinuses.
A blood clot then forms inside the
cavernous sinuses in an attempt to
prevent the infection from spreading
further into the body.
This blood clot places the brain under
increasing pressure by restricting the
blood flow, which can damage the brain,
eyes and central nervous system.
• Clinical Feature:
- a sharp and severe headache, swelling and
bulging of the eyes, eye pain that is often
severe
Cavernous sinus thrombosis (CST)
22. A 23-year-old woman with headache. CT scan demonstrates a subtle right
transverse sinus thrombosis with high attenuation (arrows). No
hemorrhagic infarction is seen.
24. • POTT'S PUFFY TUMOR
The marked swelling over the right orbit is
due to an infection of the frontal bone
(frontal sinusitis and frontal bone
osteomyelitis). In this case the infection has
spread directly to the epidural space - hence
the altered sensorium. Pott's Puffy Tumor
accounts for about 40% of epidural
abscesses; these patients are likely to
present with fever (60%), headache (40%),
nuchal rigidity (35%), seizures (10%), and
focal neurological deficits (5%).
The cause of Pott's Puffy Tumor is usually
streptococci or anaerobic organisms. Overall,
about two-thirds of intracranial abscesses
arise from infection involving the paranasal
sinuses, middle ear, or mastoid.
Osteomyelitis (POTT'S PUFFY TUMOR)
26. • Paranasal sinus mucocoeles represent
complete opacification of one or more
paranasal sinuses by mucous, often
associated with bony expansion.
• Mucoceles most likely occur as a result of
obstruction of the ostium of a sinus with
resultant accumulation of mucus and
eventual expansion of the sinus.
• The frontal sinus is particularly prone to
developing a mucocoeles, and up to two-
thirds of all mucocoeles occur there.
The ethmoidal sinuses rare the next most
common, whereas maxillary and sphenoidal
sinuses are infrequently involved.
• Mucocoeles are best imaged with a
combination of CT (to assess bony changes)
and MRI (to assess any extension into the
orbit or intracranial compartment).
Mucocoeles
CT scanning is the investigation of choice
Cerebral abscesses appear as a radiolucent space-occupying lesion
As the disease progresses, a distinctive 'ring enhancement' appears on contrast-enhanced CT, as the abscess wall thickens. They are often surrounded by oedema.
The position, size and number of abscesses may suggest underlying pathology.
