Answer for BIR CoW 31 Oct 2021
OTOMASTOIDITIS WITH PETROUS APICITIS & CAVERNOUS SINUS THROMBOSIS
Findings
MRI BRAIN & ORBIT • T2 hyper and T1 hypo intense fluid intensity signals seen within the right mastoid air cells and middle ear cavity. • Patchy areas of T2 hyperintensity involving the right petrous apex. • Foci of restricted diffusion with low ADC values in the right parasellar region and in the region of the right cavernous sinus • Subtle foci of T2 and flair hyperintensity around the right ICA cavernous segment with bulging of the lateral wall of the right cavernous sinus • Right orbital proptosis with preseptal edema. • The right superior opthalmic vien enlarged in size with loss of flow void. • Post contrast images show filling defect at the right cavernous sinus region -suggesting thrombus. Thrombosis of the right superior ophthalmic vein.
Discussion
Cavernous sinus thrombosis can have septic as well as aseptic causes, septic being much more common. It most often occurs as a complication of bacterial or fungal sepsis in the paranasal sinuses, the face, the orbits, and the skull base. More commonly it results from local spread, often from valveless facial and ophthalmic veins, more severely affecting diabetic and immunocompromised patients. Other causes include cavernous sinus compression by trauma/ tumor and prothrombotic conditions. Cavernous sinus thrombosis from a septic etiology occurs due to embolization of bacteria which trigger thrombosis that becomes trapped within the cavernous sinus. The subsequent reduction in venous drainage results in facial and periorbital edema, ptosis, proptosis, chemosis, painful eye movements, papilledema, retinal venous distension and loss of vision IMAGING FEATURES Imaging helps in identifying thrombosis either via direct visualisation of the thrombus/filling defect in cavernous sinus or via indirect signs that include proptosis, dilatation of the draining tributaries and abnormal dural enhancement, that are well demonstrated on contrast enhanced studies CT • non-contrast: high-density thrombus in affected cavernous sinus (seen in only 25%) • contrast-enhanced: distended cavernous sinus with a non-fat density filling defect • presence of sinusitis/mastoiditis, or mass lesions near the sphenoid or pituitary gland, which may indicate an underlying cavernous sinus pathology MRI • absent flow void • signal characteristics vary depending on the age of the thrombus • Absence of enhancement on contrast images • MR venography COMPLICATIONS As the dural venous and cavernous systems are valveless, communication between dural sinuses and cerebral and emissary veins can lead to meningitis, dural empyema or cerebral abscess. Propagation of infection via the internal jugular vein can result in septic pulmonary emboli, pulmonary abscess, pneumonia or empyema. Compression of the internal carotid artery and pituitary gland may result in stroke and hypopituitarism respectively.
REFERENCES
1. Absoud M, Hikmet F, Dey P et-al. Bilateral cavernous sinus thrombosis complicating sinusitis. J R Soc Med. 2006;99 : 474-6. doi:10.1258/jrsm.99.9.474 2. Razek AA, Castillo M. Imaging lesions of the cavernous sinus. AJNR Am J Neuroradiol. 2009;30 : 444-52. doi:10.3174/ajnr.A1398 3. Lee JH, Lee HK, Park JK et-al. Cavernous sinus syndrome: clinical features and differential diagnosis with MR imaging. AJR Am J Roentgenol. 2003;181 : 583-90. doi:10.2214/ajr.181.2.1810583
Findings
MRI BRAIN & ORBIT • T2 hyper and T1 hypo intense fluid intensity signals seen within the right mastoid air cells and middle ear cavity. • Patchy areas of T2 hyperintensity involving the right petrous apex. • Foci of restricted diffusion with low ADC values in the right parasellar region and in the region of the right cavernous sinus • Subtle foci of T2 and flair hyperintensity around the right ICA cavernous segment with bulging of the lateral wall of the right cavernous sinus • Right orbital proptosis with preseptal edema. • The right superior opthalmic vien enlarged in size with loss of flow void. • Post contrast images show filling defect at the right cavernous sinus region -suggesting thrombus. Thrombosis of the right superior ophthalmic vein.
Discussion
Cavernous sinus thrombosis can have septic as well as aseptic causes, septic being much more common. It most often occurs as a complication of bacterial or fungal sepsis in the paranasal sinuses, the face, the orbits, and the skull base. More commonly it results from local spread, often from valveless facial and ophthalmic veins, more severely affecting diabetic and immunocompromised patients. Other causes include cavernous sinus compression by trauma/ tumor and prothrombotic conditions. Cavernous sinus thrombosis from a septic etiology occurs due to embolization of bacteria which trigger thrombosis that becomes trapped within the cavernous sinus. The subsequent reduction in venous drainage results in facial and periorbital edema, ptosis, proptosis, chemosis, painful eye movements, papilledema, retinal venous distension and loss of vision IMAGING FEATURES Imaging helps in identifying thrombosis either via direct visualisation of the thrombus/filling defect in cavernous sinus or via indirect signs that include proptosis, dilatation of the draining tributaries and abnormal dural enhancement, that are well demonstrated on contrast enhanced studies CT • non-contrast: high-density thrombus in affected cavernous sinus (seen in only 25%) • contrast-enhanced: distended cavernous sinus with a non-fat density filling defect • presence of sinusitis/mastoiditis, or mass lesions near the sphenoid or pituitary gland, which may indicate an underlying cavernous sinus pathology MRI • absent flow void • signal characteristics vary depending on the age of the thrombus • Absence of enhancement on contrast images • MR venography COMPLICATIONS As the dural venous and cavernous systems are valveless, communication between dural sinuses and cerebral and emissary veins can lead to meningitis, dural empyema or cerebral abscess. Propagation of infection via the internal jugular vein can result in septic pulmonary emboli, pulmonary abscess, pneumonia or empyema. Compression of the internal carotid artery and pituitary gland may result in stroke and hypopituitarism respectively.
REFERENCES
1. Absoud M, Hikmet F, Dey P et-al. Bilateral cavernous sinus thrombosis complicating sinusitis. J R Soc Med. 2006;99 : 474-6. doi:10.1258/jrsm.99.9.474 2. Razek AA, Castillo M. Imaging lesions of the cavernous sinus. AJNR Am J Neuroradiol. 2009;30 : 444-52. doi:10.3174/ajnr.A1398 3. Lee JH, Lee HK, Park JK et-al. Cavernous sinus syndrome: clinical features and differential diagnosis with MR imaging. AJR Am J Roentgenol. 2003;181 : 583-90. doi:10.2214/ajr.181.2.1810583
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!