History

Fact Explanation
Majority are Asymptomatic [2] Arachnoid cysts are somewhat common. It is a neurodevelopment disorder. These cysts grow bigger with time. But even with the large cysts some patients don't show any symptom. They have normal cognitive & neurological functions. The reason is thought to be the brain's ability to compensate the slowly growing/ stably expanding intracranial cyst [1]. These are incidental findings during neuro imaging[2].
Hearing defect Patients may complain of hearing defect if the arachnoid cyst is in the CP angle( cerebello pontine angle). Other than this they might have facial paralysis on the same side[2].
Headache associated with nausea, vomiting, double vision[8]. Intra cranial arachnoid cysts are commonly found in middle fossa & left cerebral hemisphere.These are 4 times common in males than females.With the increased intracranial cranial pressure caused by mass effect of the cysts & hydrocephalus results in headaches. Migraines & cluster headaches have also reported. Arachnoid cysts in the temporal fossa result in non-specific headaches [5]. Hydrocephalus is secondary to space occupying lesions blocking Aqueduct, ventricular abnormalities, membranes occluding aqueduct or foramen of Monro.Intra cranial arachnoid cysts supposed to be caused by splitting of arachnoid membrane during neuro development, agenesis of structures of the brain, arachnoditis &active fluid secretion[2].
Abnormalities in growth & puberty Though this is a debatable fact there are some evidences that arachnoid cysts in children, according to their localizations in the brain result in endocrine disturbances like growth retardation, precocious puberty & hypothalamo-pitutary insufficiency[5].
Neuro psychiatric manifestations -musical hallucinations, attention deficits & learning difficulties -symptoms of dementia Attention deficits & learning difficulties are seen with cysts located in temporal fossa[5]. Dementia is reported in elderly patients with inter hemispheric lesions[6].
Convulsions Agenesis or dysgenesis of the cerebral temporal lobe result in seizures[8].
Acute onset symptoms following minor head trauma -accurately localized headaches, behavioral abnormality, changing personality, falling in to one side & less commonly nausea, vomiting, visual disturbances & convulsions In a patient these symptoms can be due to rupture of the cyst or rupture of the cystic vessels & bleeding in to the cyst. The mass effect of this result in the sudden onset of symptoms. This is an emergency situation[7].
Chronic low back pain, Radicular pain improving with lying down These symptoms can be there with arachnoid cysts of spine. This cysts are cerebro spinal fluid like material collected spaces situated perineural,extradural or intradural parts of spinal cord. Usually find in posterior part of the cord, but also reported in the anterior side. They are common in 1. thoracic spine 2. lumbosacral spine & 3. cervical spine respectively. Sacral arachnoid cysts are found in 40s & 50s usually & the incidence is same in male & female. There are 3 types of sacral arachnoid cysts- Type 1 is extradural cysts, Type 2 is including nerve roots( Tarlov perineural) & Type 3 is intradural cysts.Lumbosacral arachnoid cysts cause back pain, gait abnormalities & bladder,bowel abmormalities by their effects on nerves. As the lying down pushes the content out of the cyst it relives the pain[3]. Pain can be localized, referred pain in girdle fashion, groin, perineum, legs, abdominal or chest wall[10]. Patients with spinal arachnoid cysts have various neurological symptoms depending on the site (spinal cord level) & extent of lesions.Cord compression causes these[4]. The symptoms get worse with Valsalva maneuver. Some times it can even present as non cardiac chest pain, isolated urinary urgency or gait difficulty[9].
Disturbances of micturition This is an earlier presentation of cord compression. Urinary hesitansy, precipitancy can be there which leads to painless retention of urine & overflow incontinence[10].
Progressive weakness & wasting of the limbs When involve cervical spine these symptoms are in the upper limbs also. other than this they may complain of numbness & wool like feeling in the extremities[10].
References
  1. B GJERDE PRIYANTHI, SCHMID MARIT, HAMMAR ÅSA, WESTER KNUT. Intracranial arachnoid cysts: impairment of higher cognitive functions and postoperative improvement. Array [online] 2013 December [viewed 02 June 2014] Available from: doi:10.1186/1866-1955-5-21
  2. REDDY RAJAD. Intracranial arachnoid cysts. Neurol India [online] 2013 December [viewed 02 June 2014] Available from: doi:10.4103/0028-3886.107911
  3. SUNDAR IVIJAY, GOEL RAVISHANKARS, JAIN SK, SHARMA VINOD. Lumbosacral arachnoid cyst with tethered cord: A rare case report. J Craniovert Jun Spine [online] 2012 December [viewed 02 June 2014] Available from: doi:10.4103/0974-8237.116551
  4. PANIGRAHI SOUVAGYA, MISHRA SUDHANSUS, DHIR MANMATHK, PARIDA DEEPAKK. Giant thoracolumbar extradural arachnoid cyst: An uncommon cause of spine compression. Neurol India [online] 2012 December [viewed 02 June 2014] Available from: doi:10.4103/0028-3886.103217
  5. ONAL H, ADAL E, ERSEN A, IşIK O, ONAL Z, ARSLAN G. Arachnoid cysts in childhood with endocrinological outcomes. Turk J Pediatr [online] 2011 May-Jun, 53(3):295-300 [viewed 02 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/21980811
  6. KOTIL K, BALCI N, BILGE T. Intracranial symptomatic giant arachnoid cyst of the interhemispheric fissure presenting with frontal lobe syndrome. Turk Neurosurg [online] 2007 Apr, 17(2):147-51 [viewed 02 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/17935034
  7. DE K, BERRY K, DENNISTON S. Haemorrhage into an arachnoid cyst: a serious complication of minor head trauma. Emerg Med J [online] 2002 Jul, 19(4):365-6 [viewed 02 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/12101165
  8. AN DER MECHé FG, BRAAKMAN R. Arachnoid cysts in the middle cranial fossa: cause and treatment of progressive and non-progressive symptoms. J Neurol Neurosurg Psychiatry [online] 1983 Dec, 46(12):1102-7 [viewed 02 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/6663308
  9. HUGHES G, UGOKWE K, BENZEL EC. A review of spinal arachnoid cysts. Cleve Clin J Med [online] 2008 Apr, 75(4):311-5 [viewed 03 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/18491438
  10. HARRIES B. Spinal cord compression. Br Med J [online] 1970 Mar 7, 1(5696):611-4 [viewed 04 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/5440240

Examination

Fact Explanation
Abnormal shape & volume of the skull- cranial deformity & macrocephaly[5] When the cyst is there since the early childhood, the skull grows in to an abnormal shape as it gives space to the expanding cyst. [1]
Sensoneural hearing loss This happens when the cysts are located in cerebellopontine angle[2]. Cyst compress the VIII cranial nerve resulting in ipsilateral sensoneural hearing defect.
Lower motor type facial nerve palsy This also happens when the cysts are located in cerebellopontine angle[2]. Cyst compresses the VII cranial nerve resulting in weakness of the ipsilateral half of the face.
Diplopia This is caused by increased intra cranial pressure[5].
Papillioedma on funduscopy This is caused by increased intra cranial pressure[5].
Findings of the limbs....eg lower limbs - Power less than grade 5 - Absent/ diminished deep tendon reflexes - gait abnormalities -sensory levels eg..These signs can be there with arachnoid cysts of lumbosacral spine.Lumbosacral arachnoid cysts cause the lower moter type weakeness in the lower limbs[3]. Patients with spinal arachnoid cysts have various neurological signs depending on the site (spinal cord level) & extent of lesions.Cord compression causes the signs. These can be paresis, sensory impairment, autonomic disturbances and gait abnormalities.[4]
References
  1. B GJERDE PRIYANTHI, SCHMID MARIT, HAMMAR ÅSA, WESTER KNUT. Intracranial arachnoid cysts: impairment of higher cognitive functions and postoperative improvement. Array [online] 2013 December [viewed 02 June 2014] Available from: doi:10.1186/1866-1955-5-21
  2. REDDY RAJAD. Intracranial arachnoid cysts. Neurol India [online] 2013 December [viewed 02 June 2014] Available from: doi:10.4103/0028-3886.107911
  3. SUNDAR IVIJAY, GOEL RAVISHANKARS, JAIN SK, SHARMA VINOD. Lumbosacral arachnoid cyst with tethered cord: A rare case report. J Craniovert Jun Spine [online] 2012 December [viewed 02 June 2014] Available from: doi:10.4103/0974-8237.116551
  4. PANIGRAHI SOUVAGYA, MISHRA SUDHANSUS, DHIR MANMATHK, PARIDA DEEPAKK. Giant thoracolumbar extradural arachnoid cyst: An uncommon cause of spine compression. Neurol India [online] 2012 December [viewed 02 June 2014] Available from: doi:10.4103/0028-3886.103217
  5. AN DER MECHé FG, BRAAKMAN R. Arachnoid cysts in the middle cranial fossa: cause and treatment of progressive and non-progressive symptoms. J Neurol Neurosurg Psychiatry [online] 1983 Dec, 46(12):1102-7 [viewed 02 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed

Differential Diagnoses

Fact Explanation
Cholesteatoma & cholesterol granuloma Considering Petrous apex these two lesions are more common than arachnoid cysts. Cholesteatoma & arachnoid cyst both appear in MRI as non enhancing, hypointense on T1 weighted, hyper intense on T2 weighted images.[1]
extramedullary ependymoma radiological features & clinical features mimic that of arachnoid cysts[2].
epidermoid cysts They have hyperintense FLAIR MRI sequence & high signal intensity on diffusion sequence. In both sequences arachnoid cysts has low intensity[3].
chronic subdural haematoma These do not show the equal signal intensity of cerebro spinal fluid in MRI[3].
Porencephalic cysts These are filled in cerebro spinal fluid. They have thin wall covered with white matter[3].
References
  1. ACHILLI V, DANESI G, CAVERNI L, RICHICHI M. Petrous apex arachnoid cyst: a case report and review of the literature. Acta Otorhinolaryngol Ital [online] 2005 Oct, 25(5):296-300 [viewed 03 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/16602329
  2. GRAçA J, GüLTASLI N, D'HAENE N, BROTCHI J, SALMON I, BALéRIAUX D. Cystic extramedullary ependymoma. AJNR Am J Neuroradiol [online] 2006 Apr, 27(4):818-21 [viewed 03 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/16611771
  3. OPRIşAN ALEXANDRA, POPESCU BOGDAN O.. Intracranial Cysts: An Imagery Diagnostic Challenge. The Scientific World Journal [online] 2013 December, 2013:1-9 [viewed 03 June 2014] Available from: doi:10.1155/2013/172154

Investigations - for Diagnosis

Fact Explanation
MRI scan spine This has the highest sensitivity & specificity to identify spinal arachnoid cysts. MRI scans asses the extents of the walls of the cysts. It can differentiate arachnoid cysts from other cystic tumors of the spine. [1]
CT myelography This helps to find out if there is communication between intraspinal subarachnoid space & arachnoid cyst. But this doesn't locate the communication. [1]
MRI scan & CT scan brain This is to identify intracranial arachnoid cysts. These show equal signal sequences as cerebro spinal fluid. They appear round , non contrast enhancing lesions. Sometimes they can show signs of hemorrhages in MRI[2].
cine- MRI (12 Kine matic MRI) This locate the communication. It shows it as a pulsating turbulent flow. So this helps to limit the surgical approach. [1]
References
  1. SUNDAR IVIJAY, GOEL RAVISHANKARS, JAIN SK, SHARMA VINOD. Lumbosacral arachnoid cyst with tethered cord: A rare case report. J Craniovert Jun Spine [online] 2012 December [viewed 02 June 2014] Available from: doi:10.4103/0974-8237.116551
  2. OPRIşAN ALEXANDRA, POPESCU BOGDAN O.. Intracranial Cysts: An Imagery Diagnostic Challenge. The Scientific World Journal [online] 2013 December, 2013:1-9 [viewed 03 June 2014] Available from: doi:10.1155/2013/172154

Investigations - Followup

Fact Explanation
Neuro imagine -regular CT scans Patients followed with CT scans once in 3 months for the first year, then annually. It shows the size of the cyst & also the change mass effect[1]. Assessing the patient's clinical improvement is important.
References
  1. YOU CHAO, WANG CHAO, LIU CHUANGXI, XIONG YUNBIAO, HAN GUOQIANG, YANG HEN, YIN HAO, WANG JUN. Surgical treatment of intracranial arachnoid cyst in adult patients. Neurol India [online] 2013 December [viewed 03 June 2014] Available from: doi:10.4103/0028-3886.108013

Investigations - Screening/Staging

Fact Explanation
prenatal diagnosis using ultrasound scans This is possible even in first trimester. As the prognosis can not be predicted in first trimester, it is advisable to ask the parents to wait till second trimester before decision making[1].
References
  1. BRETELLE F, SENAT MV, BERNARD JP, HILLION Y, VILLE Y. First-trimester diagnosis of fetal arachnoid cyst: prenatal implication. Ultrasound Obstet Gynecol [online] 2002 Oct, 20(4):400-2 [viewed 03 June 2014] Available from: doi:10.1046/j.1469-0705.2002.00813.x

Management - General Measures

Fact Explanation
Watch & wait This is for the incidentally diagnosed, asymptomatic arachnoid cysts. Annually imaging is done to detect any new abnormalities of the cyst...eg size of the cyst. If symptoms begins evaluate with a MRI scan [1].Spontaneous disappearance is also reported[2]. Educate the patient about the disease & possible symptoms.
References
  1. HUGHES G, UGOKWE K, BENZEL EC. A review of spinal arachnoid cysts. Cleve Clin J Med [online] 2008 Apr, 75(4):311-5 [viewed 03 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/18491438
  2. MATUSHITA H, CARDEAL DD, MONACO B. Spontaneous disappearance of cerebral convexity arachnoid cyst. Arq Neuropsiquiatr [online] 2012 Jun, 70(6):473-4 [viewed 03 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/22699549

Management - Specific Treatments

Fact Explanation
Cyst fenestration Surgical treatment is necessary in symptomatic patients with increased intra cranial pressure. And also when there is intra cystic or subdural hemorrhages though arachnoid cysts are communicating type. Cyst fenestration or the resection allow the histological confirmation. But the recurrence is common following resection.Apart from been invasive reported post -op complications are meningitis, subdural/ intraparenchymal hemorrhages & inability to treat hydrocephalus[2].
Shunting procedures As this is a simple, safe & effective method shunting is used to manage middle fossa cysts. But been a blind procedure there is a risk to fail reach inside the cyst. Surgical accidents are also common with this. The other disadvantages are shunt infection, deficiency, inability to treat multiple cysts & other associated lesions & recurrence[2].
Endoscopic fenestration This endoscopic procedures are better alternatives for surgical & shunting procedures. This is an effective & safe method which is minimally invasive. Symptoms also improve rapidly & completely[2].
Treatments for spinal arachnoid cysts complete resection This is the ideal method of treatment.Very effective & results in excellent outcomes. But if the cyst is not fully resectable, then draining of the cyst is done...eg extensive adhesions. In such situations fenestration of the wall & shunting is carried out. Endoscopic procedures also have employed[3].
CT guided per-cutaneous injection of fibrin glue This is a non surgical method of treating symptomatic sacral arachnoid cysts. With surgical decompression risk of recurrence & post operative complications are high. And also surgeries are invasive. Comparing to surgical decompression this is a non-invasive, safe, simple & effective method. [1]
References
  1. SHAO Z., WANG B., WU Y., ZHANG Z., WU Q., YANG S.. CT-Guided Percutaneous Injection of Fibrin Glue for the Therapy of Symptomatic Arachnoid Cysts. American Journal of Neuroradiology [online] December, 32(8):1469-1473 [viewed 03 June 2014] Available from: doi:10.3174/ajnr.A2595
  2. KIM MH. The role of endoscopic fenestration procedures for cerebral arachnoid cysts. J Korean Med Sci [online] 1999 Aug, 14(4):443-7 [viewed 03 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/10485626
  3. HUGHES G, UGOKWE K, BENZEL EC. A review of spinal arachnoid cysts. Cleve Clin J Med [online] 2008 Apr, 75(4):311-5 [viewed 03 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/18491438