Answer for BIR CoW 23 Oct 2022
Sinking Flap Syndrome with recurrent coalescent left ear mastoiditis with cerebellar abscess and meningitis
Findings
Multiple peripherally enhancing T1 hypointense/T2 hyperintense lesion with surrounding edema in left cerebellar region showing diffusion restriction with low ADC values , largest measuring 1.8x1.4 cm causing mass effect over pons , medulla and vermis
Peripherally enhancing T2 hypointense well defined collection in left mastoid region , with lytic erosion of mastoid part of temporal bone posteriorly , showing diffusion restriction with low ADC values , along with leptomeningeal enhancement of left tentorium and temporal region
Large left hemicraniectomy defect appears depressed with concavity of the overlying skin flap with mild adjoining T2 hyperintensity showing dural enhancement in left frontotemporoparietal region
Cystic encephalomalacic changes in left temporal lobe with exvacuo dilatation of temporal horn of lateral ventricle with white matter edema
Subgaleal collection in left parietal region
Impression
Known case of Otogenicbrain abscess due to complicated left ear mastoiditis with post left frontotemporoparietal craniectomy defect which appears depressed – Sinking flap syndrome
Recurrent coalescent left ear mastoiditis with confluent cerebellar abscess with meningitis
Discussion
The sinking skin flap syndrome (SSFS) or syndrome of the trephined is a rare complication that occurs in approximately 10% of large craniectomies and tends to develop several weeks to several months after surgery. It consists of a sunken scalp above the bone defect with neurological symptoms. Clinical findings may range from asymptomatic to a monosymptomatic state to an acute neurological deterioration.The principal symptoms are severe orthostatic headache, motor deficits, cognitive decline or seizures. The SSFS may progress to “paradoxical hernia” and eventually lead to coma or death without treatment. Several hypothesis have been proposed to explain the physiopathology of this syndrome which nevertheless remains unclear. One theory suggests a direct compression of the brain by the atmospheric pressure to the intracranial cavity through the skin scalp. Another hypothesis proposed that the difference between atmospheric and intracranial pressure may lead to hypovolemia and/or hypopressure in the cerebrospinal fluid (CSF). CSF drainage such as external ventriculostomies, ventriculoperitoneal shunts, or after lumbar punctures can aggravated this condition. Some authors suggest that craniectomy may induce significant alterations in blood flow regulation mechanisms. All these hypothesis may contribute to decreased regional cerebral blood flow and metabolic changes causing cortical dysfunction and neurological deficits . CT scan revealed a large craniectomy with concavity of the overlying skin scalp, with mass effect such as sulci effacement and midline shift in the opposite direction of the scalp, also referred to as ‘paradoxical hernia.’ The final treatment is cranioplasty with replacement of the cranial flap but surgery is often delayed for many reasons like infections. During this time, measures are needed to raise the intracranial pressure like Trendelenburg position, hydration and clamping of CSF drainage.
Otogenic brain abscess due to complicated mastoiditis – Uncommon but severe complication of otitis media resulting in subdural and cerebellar abscess. This advanced presentation requires urgent intervention due to compression of the fourth ventricle resulting in hydrocephalus and cerebellar tonsillar herniation
Findings
Multiple peripherally enhancing T1 hypointense/T2 hyperintense lesion with surrounding edema in left cerebellar region showing diffusion restriction with low ADC values , largest measuring 1.8x1.4 cm causing mass effect over pons , medulla and vermis
Peripherally enhancing T2 hypointense well defined collection in left mastoid region , with lytic erosion of mastoid part of temporal bone posteriorly , showing diffusion restriction with low ADC values , along with leptomeningeal enhancement of left tentorium and temporal region
Large left hemicraniectomy defect appears depressed with concavity of the overlying skin flap with mild adjoining T2 hyperintensity showing dural enhancement in left frontotemporoparietal region
Cystic encephalomalacic changes in left temporal lobe with exvacuo dilatation of temporal horn of lateral ventricle with white matter edema
Subgaleal collection in left parietal region
Impression
Known case of Otogenicbrain abscess due to complicated left ear mastoiditis with post left frontotemporoparietal craniectomy defect which appears depressed – Sinking flap syndrome
Recurrent coalescent left ear mastoiditis with confluent cerebellar abscess with meningitis
Discussion
The sinking skin flap syndrome (SSFS) or syndrome of the trephined is a rare complication that occurs in approximately 10% of large craniectomies and tends to develop several weeks to several months after surgery. It consists of a sunken scalp above the bone defect with neurological symptoms. Clinical findings may range from asymptomatic to a monosymptomatic state to an acute neurological deterioration.The principal symptoms are severe orthostatic headache, motor deficits, cognitive decline or seizures. The SSFS may progress to “paradoxical hernia” and eventually lead to coma or death without treatment. Several hypothesis have been proposed to explain the physiopathology of this syndrome which nevertheless remains unclear. One theory suggests a direct compression of the brain by the atmospheric pressure to the intracranial cavity through the skin scalp. Another hypothesis proposed that the difference between atmospheric and intracranial pressure may lead to hypovolemia and/or hypopressure in the cerebrospinal fluid (CSF). CSF drainage such as external ventriculostomies, ventriculoperitoneal shunts, or after lumbar punctures can aggravated this condition. Some authors suggest that craniectomy may induce significant alterations in blood flow regulation mechanisms. All these hypothesis may contribute to decreased regional cerebral blood flow and metabolic changes causing cortical dysfunction and neurological deficits . CT scan revealed a large craniectomy with concavity of the overlying skin scalp, with mass effect such as sulci effacement and midline shift in the opposite direction of the scalp, also referred to as ‘paradoxical hernia.’ The final treatment is cranioplasty with replacement of the cranial flap but surgery is often delayed for many reasons like infections. During this time, measures are needed to raise the intracranial pressure like Trendelenburg position, hydration and clamping of CSF drainage.
Otogenic brain abscess due to complicated mastoiditis – Uncommon but severe complication of otitis media resulting in subdural and cerebellar abscess. This advanced presentation requires urgent intervention due to compression of the fourth ventricle resulting in hydrocephalus and cerebellar tonsillar herniation
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!