Lateral sinus thrombosis is a complication of chronic suppurative otitis media (CSOM) where infection spreads from the middle ear to the lateral sinus through bone erosion or thrombophlebitis of emissary veins. It can cause symptoms like fever, headache, and neurological deficits depending on the stage of infection. Diagnosis is made through imaging modalities like CT and MRI scans. Treatment involves long-term intravenous antibiotics and possible surgical drainage of infection and removal of blood clots from the sinus. Even with treatment, lateral sinus thrombosis carries risks of complications and death in some cases.

1. Lateral Sinus Thrombosis
A Complication of CSOM

2. Overview
• 6% of all Intracranial complications of CSOM
• In CSOM direcrt spread through bone erosion
and thrombophlebitic spread through
emissary veins
• In ASOM spread is mainly through emissary
veins

3. Anatomy
• Formed by the confluence of the superior
petrosal and transverse sinuses
• Becomes internal jugular vein at its exit from
foramen jugulare

6. Spread
• Directly through bone erosion due to
granulation and cholesteatoma
• Thrombophlebitis of the mastoid emissary
veins
– Griesinger’s Sign
– Erythema, edema and tenderness over mastoid area

9. Pathophysiology
• Perisinus abscess  penetrates dura  reaches
intima  mural thrombus forms due to intimal
damage, hypercoagulation and blood flow in sinus
• Bacteria & thrombus  platelet aggregtion  fibrin
formation  mural clot  necrosis of clot 
intramural abscess
• Clot propagates  occlusion of vessel lumen &
infected emboli given off in circulation  metastatic
abscesses  septicemia

11. Presentation
• Varies according to stage

14. Presentation Contd.
• Despite antibiotics may present as
– Fever with periodic chills
– Picket fence due to periodic release of steptococci in blood from
septic thrombus
– Headache
– Due to raised ICP caused by interrupted cortical venous circulation
 Papilledema
– Otorrhoea
– Refractory to antibiotic therapy
– Neck Pain
– Extension of thrombophlebitis to jugular bulb and internal jugular
vein  IJV palpated as a tender cord in neck

15. Presentation Cont.
– Neck rigidity
– Due to meningeal irritation. Torticollis may also be seen due to
guarding of the neck muscles
– Nausea, vomiting
– Due to raised ICP and bacteremia
– Altered mental state and focal neurologic signs
– If brain abscess
– Vertigo and nystagmus
– Involvement of labyrinth
– Seizures
– Temporal lobe involvement
– Lethargy

16. Presentation Cont.
• Jugular Foramen Syndrome-Vernet’s Syndrome
- Dysphonia/hoarseness
- Soft palate dropping
- deviation of the uvula towards the normal side
- dysphagia
- loss of sensory function from the posterior 1/3 of the
tongue
- decrease in the parotid gland secretion
- loss of gag reflex
- Sternocleidomastoid and trapezius muscles paresis

17. Presentation Cont.
• Jugular Foramen Syndrome-Vernet’s Syndrome
– 9th
, 10th
& 11th
and sometimes 12th
nerve paralysis due to
pressure of clot in jugular bulb
– Symptoms
» pain in or behind ear due to irritation of the auricular
branches of the 9th
and 10th
nerves
» headache due to irritation of the meningeal branch of vagus
» hoarseness due to paralysis of the laryngeal nerves
» dysphagia (diffiuclty to swallow) due to paralysis of the
pharyngomotor fibres
» honers syndrome ( ptosis of upper eyelid, pupillary
constriction) due to interruption of sympathetic internal
caortid plexus
» wasting of affected side of tongue and deviation of the
protruded tongue to the affected side due to infranuclear
paralysis of 12th
nerve

18. Presentation Cont.
» deviation of the uvula away form the affected side due to
unopposed action of levator palatini
» sensory loss in oroharynx on the affected side
» inabllity to adduct the vocal cords to the midline
» weakness and wasting of sternocleidomastoid and
treapezius due to involvement of 11th
nerve
sympathetic signs may be absent if accessory nerve
unaffected
– Recovery depends on collateral circulation and
recanalization of the sinus
– Surgical intervention not required usually
– Decompression and removal of clot if necessary

20. Presentation Cont.
• Otitic Hydrocephalus
– Due to interrupted cortical venous circulation
obstruction in CSF flow leads to ventricular
dilatation
– One or both lateral sinuses may be found
thrombosed
– S&S of raised ICP`

21. Clinical Examination
• Anaemia & emaciation
• Griesingers’s sign
• Positive Tobey – Ayer’s Test
• Positive Crow – Beck’s Test
• Tenderness along IJV
• Enlarged jugular nodes
• Torticollis
• Positive Kernig’s Sign
• Positive Brudzinski’s Sign

23. Bacteriology
• Acute
– Hemolytic stretpococci
– Pneumococci
– Staphylococci
• Chronic
– Bacillus Proteus
– Pseudomonas Pyocyaneus
– E.coli
– Bacteroides
– Staphylococci

24. Labs
• Polys on CBC
• CSF examination ICP only
• C/S of ear swab
• C/S of pus material from sinus if available

25. Imaging
• CT with contrast  Delta Sign
• Gadolinium enhanced MRI  Delta Sign
– MRI is the investigation of choice & is done in
combination with CT
• Serial MRV in combination with MRI to see
clot propagation and resolution

26. Treatment
• Medical + Surgical  Combo
• Medical
– I/V antibiotics
– Anti coagulants only if clot in superior sagittal
sinus or ICP persists despite medical
management

27. Treatment Contd.
• Surgical
• Mastoidectomy + removal of clot from sinus
– ASOM
– Cortical + removal of sinus plate
– CSOM + Cholesteatoma
– Radical
– Refractory Septicemia
– IJV ligation to stop emboli being thrown into circulation

28. Follow up
• Post op antibiotics for 2-3 weeks
• Post op MRI & MRV

29. Complications
• Mostly ipsilateral
• At times contralateral due to hematogenous
spread

30. Prognosis
• Mortality has decreased to less than 10% due
to availability of effective medical and surgical
treatment

34. Name No. Drains to / Becomes
Inferior Sagittal Sinus 1 Straight sinus
Superior Sagittal Sinus 1 Becomes right transverse sinus or confluence of
sinuses
Straight Sinus 1 Becomes left transverse sinus or confluence of
sinuses
Occipital Sinus 1 Confluence of sinuses
Confluence Of Sinuses 1 Right and left transverse sinuses
Sphenoparietal Sinuses 2 Cavernous sinuses
Intercavernous Sinuses 2 Cavernous sinuses
Cavernous Sinuses 2 Superior and inferior petrosal sinuses
Superior & Inferior Petrosal
Sinuses
2/2 Transverse sinuses
Transverse Sinuses 2 Sigmoid sinusees
Sigmoid Sinuses 2 Jugular bulb  IJV