Encephalitis

Neurology

Clinicals - History

Fact Explanation
Fever Encephalitis is an inflammation of the brain parenchyma. Herpes simplex is one of the fastest replicating viruses that accounts for encephalitis. Once the person is exposed to infected saliva or respiratory secretions, virus ascends along the olfactory nerve into the limbic lobe, or it may be reactivation of virus from Trigeminal ganglion. Flavivirus infection, is also known to cause japanese encephalitis which has a fatality of 60%. Varizella zoster, tuberculosis, mumps, measles are the other major causative agents. Once entered into the brain, it causes axonal spread to newly infected regions in the brain, that damages the brain by direct lysis of cells or, later, virus-induced damage causing further destruction accompanied by host's immune responses. 90% of patients show evidence of temporal lobe involvement. Inflammation of the meninges, brain matter and endothelium releases pyrogens causing fever. Fever
Encephalitis is an inflammation of the brain parenchyma. Herpes simplex is one of the fastest replicating viruses that accounts for encephalitis. Once the person is exposed to infected saliva or respiratory secretions, virus ascends along the olfactory nerve into the limbic lobe, or it may be reactivation of virus from Trigeminal ganglion. Flavivirus infection, is also known to cause japanese encephalitis which has a fatality of 60%. Varizella zoster, tuberculosis, mumps, measles are the other major causative agents. Once entered into the brain, it causes axonal spread to newly infected regions in the brain, that damages the brain by direct lysis of cells or, later, virus-induced damage causing further destruction accompanied by host's immune responses. 90% of patients show evidence of temporal lobe involvement. Inflammation of the meninges, brain matter and endothelium releases pyrogens causing fever.
Headache Pathogens may cross the BBB transcellularly (through human brain microvascular endothelial cells), paracellularly(penetration between barrier cells with and/or without disruption of tight junctions) and “Trojan horse” mechanism(penetration of the barrier cells using transmigration within infected phagocyte) . Once the organism entered through the blood brain barrier, immune system of the body gets activated to release various cytokines and chemikines. Further it releases reactive oxygen radicals to cause more endothelial and nearby tissue damage. These can cause meningeal irritation, increased intracranial pressure and cerebral edema. Headache
Pathogens may cross the BBB transcellularly (through human brain microvascular endothelial cells), paracellularly(penetration between barrier cells with and/or without disruption of tight junctions) and “Trojan horse” mechanism(penetration of the barrier cells using transmigration within infected phagocyte) . Once the organism entered through the blood brain barrier, immune system of the body gets activated to release various cytokines and chemikines. Further it releases reactive oxygen radicals to cause more endothelial and nearby tissue damage. These can cause meningeal irritation, increased intracranial pressure and cerebral edema.
Seizures Altered cerebral perfusion pressure can cause reduction of the cerebral blood flow and ischaemia. This also might represent viral invasion and destruction of neuronal cells. Seizures
Altered cerebral perfusion pressure can cause reduction of the cerebral blood flow and ischaemia. This also might represent viral invasion and destruction of neuronal cells.
Decreased alertness, drowsiness There can be increased intracranial pressure which may be due to the increased blood brain barrier permeability, swelling of the cellular elements of the brain, interstitial edema results from obstruction of flow in normal CSF pathways etc. Neuronal cell death and cerebral edema may also contribute to the drowsiness. Decreased alertness, drowsiness
There can be increased intracranial pressure which may be due to the increased blood brain barrier permeability, swelling of the cellular elements of the brain, interstitial edema results from obstruction of flow in normal CSF pathways etc. Neuronal cell death and cerebral edema may also contribute to the drowsiness.
Behavioural changes Temporal lobe involvement is common in encephalitis. Behavioural abnormalitieS are occurred due to this and odd behaviour may be an earliest symptom. Behavioural changes
Temporal lobe involvement is common in encephalitis. Behavioural abnormalitieS are occurred due to this and odd behaviour may be an earliest symptom.
Sensitivity to light (photophobia), Pain during retraction of the neck Inability to tolerate light due to the associated meningoencephalitis. Neck stiffness is due to the meningeal irritation. Sensitivity to light (photophobia), Pain during retraction of the neck
Inability to tolerate light due to the associated meningoencephalitis. Neck stiffness is due to the meningeal irritation.
Vomiting Vomiting is a common finding in meningoencephalitis. Vomiting
Vomiting is a common finding in meningoencephalitis.
Excessive crying, refusing the feeds Infants and young children present with nonspecific features. Excessive crying, refusing the feeds
Infants and young children present with nonspecific features.
Hearing loss Inflammation can extends to the cranial nerves, when the 8th nerve is involved that causes sensorineural type hearing loss. Hearing loss
Inflammation can extends to the cranial nerves, when the 8th nerve is involved that causes sensorineural type hearing loss.
Visual problems Visual problems Involvement of the optic and other cranial nerves related to the vision can be the cause. Visual problems
Visual problems Involvement of the optic and other cranial nerves related to the vision can be the cause.
History of immunodeficiency People with immune deficiency like malignancy, patients on chemotherapy, long term steroid use, organ transplant and HIV AIDS are particularly vulnerable for the disease. History of immunodeficiency
People with immune deficiency like malignancy, patients on chemotherapy, long term steroid use, organ transplant and HIV AIDS are particularly vulnerable for the disease.
History of malignancy They can develop paraneoplastic encephalitis. History of malignancy
They can develop paraneoplastic encephalitis.

Clinicals - Examination

Fact Explanation
Febrile Fever is one of the commonest presenting features. Febrile
Fever is one of the commonest presenting features.
Mental status changes Alteration in mental status is a poor prognostic indicator. Mental status changes
Alteration in mental status is a poor prognostic indicator.
Unconsciousness and coma Coma is a severe form of altered level of consciousness. State of unarousable unconsciousness with no response to external stimuli. Patient appears to be asleep. Unconsciousness and coma
Coma is a severe form of altered level of consciousness. State of unarousable unconsciousness with no response to external stimuli. Patient appears to be asleep.
Stiff neck Due to the meningeal irritation. Stiff neck
Due to the meningeal irritation.
Kernig sign and brudzinki sign Kernig sign a is a bedside diagnostic sign used to evaluate suspected cases of meningitis. Patient is kept in supine position, hip and knee are flexed, the knee is slowly extended by the examiner. It is positive if there is a resistance or pain during extension.
Another sign of meningeal irritation is Brudzinki sign . First one hand is kept behind the patient's head and the other on chest in order to prevent the patient from rising, passive flexion of the neck produces reflex flexion of the patient's hips and knees in a positive Brudzinski's sign.
Kernig sign and brudzinki sign
Kernig sign a is a bedside diagnostic sign used to evaluate suspected cases of meningitis. Patient is kept in supine position, hip and knee are flexed, the knee is slowly extended by the examiner. It is positive if there is a resistance or pain during extension.
Another sign of meningeal irritation is Brudzinki sign . First one hand is kept behind the patient's head and the other on chest in order to prevent the patient from rising, passive flexion of the neck produces reflex flexion of the patient's hips and knees in a positive Brudzinski's sign.
Tachycardia Tachycardia or a fast heart rate is observed in hypotensive, confused patients. Tachycardia
Tachycardia or a fast heart rate is observed in hypotensive, confused patients.
Focal neurological signs Mostly cerebral involvement affects the temporal lobe causing hemiparesis, speech disturbances and odd behaviour. Cerebral-space-occupying lesions such as abscess formation can also cause these symptoms. Focal neurological signs
Mostly cerebral involvement affects the temporal lobe causing hemiparesis, speech disturbances and odd behaviour. Cerebral-space-occupying lesions such as abscess formation can also cause these symptoms.
Buldging of fontanelle Due to the increased intracranial pressure. Buldging of fontanelle
Due to the increased intracranial pressure.
Growth retardation Ischaemia can cause neuronal cell death and tissue damage, if the developing brain is affected with permanent neuropsychiatric sequelae child may ends up with poor growth. Growth retardation
Ischaemia can cause neuronal cell death and tissue damage, if the developing brain is affected with permanent neuropsychiatric sequelae child may ends up with poor growth.
Sensorineural hearing loss Braistem encephalitis may cause cranial nerve palsies specially VIII the nerve palsy is the cause for this hearing loss. Sensorineural hearing loss
Braistem encephalitis may cause cranial nerve palsies specially VIII the nerve palsy is the cause for this hearing loss.
Papilloedema This is due to the increased intracranial pressure. Increased blood brain barrier permeability, swelling of the cellular elements of the brain, interstitial edema results from obstruction of flow in normal CSF pathways as in hydrocephalus are the possible causes for the raised intracranial pressure. Papilloedema
This is due to the increased intracranial pressure. Increased blood brain barrier permeability, swelling of the cellular elements of the brain, interstitial edema results from obstruction of flow in normal CSF pathways as in hydrocephalus are the possible causes for the raised intracranial pressure.
Diplopia Is seen as a visual probleM. Diplopia
Is seen as a visual probleM.
Other manifestations of Herpes Simplex Virus Genital herpes may cause vesicles, gingivostomatis,eczema herpeticum which is an eczematous skin lesion, redness, watering, discharge, itching, irritation, and lid swelling, lid vesicles and ulcers. Other manifestations of Herpes Simplex Virus
Genital herpes may cause vesicles, gingivostomatis,eczema herpeticum which is an eczematous skin lesion, redness, watering, discharge, itching, irritation, and lid swelling, lid vesicles and ulcers.

Investigations - Diagnosis

Fact Explanation
Lumbar puncture Opening pressure will be elevated. Predominantly mononuclear pleocytosis with elevated lymphocytes an elevated CSF protein, reduced CSF glucose <40 mg/dL is seen. Fewer inflammatory cells are observed among AIDS patients due to the lack of a vigorous cellular immune response. Viral cultures of CSF, including HSV should be done. Polymerase chain reaction (PCR) of the cerebrospinal fluid (CSF) is the diagnostic method for herpes encephalitis. Lumbar puncture
Opening pressure will be elevated. Predominantly mononuclear pleocytosis with elevated lymphocytes an elevated CSF protein, reduced CSF glucose <40 mg/dL is seen. Fewer inflammatory cells are observed among AIDS patients due to the lack of a vigorous cellular immune response. Viral cultures of CSF, including HSV should be done. Polymerase chain reaction (PCR) of the cerebrospinal fluid (CSF) is the diagnostic method for herpes encephalitis.
Blood culture Blood culture done if the patient seems to be septic or lumbar puncture can not be done safely due to the possibility of increased intracranial pressure before the specific treatment. Blood culture
Blood culture done if the patient seems to be septic or lumbar puncture can not be done safely due to the possibility of increased intracranial pressure before the specific treatment.
Computer tomography(CT) scan of the head and Magnetic Resonance Imaging (MRI) CT scan will be even better as the first investigation specially to rule out the possibility of increased intracranial pressure before doing lumbar puncture. CT will reveal several foci in medial temporal lobes and inferior frontal gray matter with increased T2 signal intensity in encephalitis. It is also helpful to evaluate the presence of any haemorrhages and infarctions. Thalamic hyperintensity in magnetic resonance imaging (MRI) is a specific finding which could be very useful in diagnosing Japanese encephalitis. MRI will demonstrate the inflammatory dural meningeal process with enhanced uptake over the affected areas in associated meningoencephalitis. . This also show the complications like hydrocephalus. Computer tomography(CT) scan of the head and Magnetic Resonance Imaging (MRI)
CT scan will be even better as the first investigation specially to rule out the possibility of increased intracranial pressure before doing lumbar puncture. CT will reveal several foci in medial temporal lobes and inferior frontal gray matter with increased T2 signal intensity in encephalitis. It is also helpful to evaluate the presence of any haemorrhages and infarctions. Thalamic hyperintensity in magnetic resonance imaging (MRI) is a specific finding which could be very useful in diagnosing Japanese encephalitis. MRI will demonstrate the inflammatory dural meningeal process with enhanced uptake over the affected areas in associated meningoencephalitis. . This also show the complications like hydrocephalus.
Electroencephalogram EEG is often abnormal with diffuse slowing or uni or bilateral temporal periodic discharges or low wave complexes at 2-3/second interval. Electroencephalogram
EEG is often abnormal with diffuse slowing or uni or bilateral temporal periodic discharges or low wave complexes at 2-3/second interval.
Full blood count There can be elevated lymphocytes, it is also important to exclude the other causes for the fever such as low platelets in viral infections, high white blood cells (leucocytosis) in bacterial infections. Full blood count
There can be elevated lymphocytes, it is also important to exclude the other causes for the fever such as low platelets in viral infections, high white blood cells (leucocytosis) in bacterial infections.

Investigations - Management

Fact Explanation
Polymerase chain reaction (PCR) After completion of antiviral therapy, PCR of the CSF may be needed to confirm the elimination of replicating virus. Polymerase chain reaction (PCR)
After completion of antiviral therapy, PCR of the CSF may be needed to confirm the elimination of replicating virus.
Erythrocyte sedimentation rate(ESR) and C Reactive protein(CRP) Is elevated due to the inflammation. Erythrocyte sedimentation rate(ESR) and C Reactive protein(CRP)
Is elevated due to the inflammation.
Renal functions and serum electrolytes Syndrome of inappropriate Antidiuretic Hormone secretion is a complication of encephalitis. This can cause hyponatraemia. Reduced intake of fluids can cause electrolyte imbalances. Medications may alter the renal functions and therefore baseline value is also needed. Renal functions and serum electrolytes
Syndrome of inappropriate Antidiuretic Hormone secretion is a complication of encephalitis. This can cause hyponatraemia. Reduced intake of fluids can cause electrolyte imbalances. Medications may alter the renal functions and therefore baseline value is also needed.
Liver function tests Medications may alter the liver functions and therefore baseline value is needed before the treatment. Liver function tests
Medications may alter the liver functions and therefore baseline value is needed before the treatment.
Random blood sugar Should be done immediately especially if the patient is drowsy, to rule out the hypoglycaemia as cause for drowsiness. Random blood sugar
Should be done immediately especially if the patient is drowsy, to rule out the hypoglycaemia as cause for drowsiness.
MRI/CT brain Increased intracranial pressure is evident on MRI by severe sulcal effacement and midline shift on brain imaging. MRI/CT brain
Increased intracranial pressure is evident on MRI by severe sulcal effacement and midline shift on brain imaging.
HIV screening Those who accept HIV screening should have the antibody check up as these infections are common in people infected with HIV. HIV screening
Those who accept HIV screening should have the antibody check up as these infections are common in people infected with HIV.
Thick and thin blood films for malaria Cerebral malaria needs to be excluded. Thick and thin blood films for malaria
Cerebral malaria needs to be excluded.

Management - Supportive

Fact Explanation
Immediate management This is particularly important if the patient presents with confusion and drowsiness. Airway, breathing, circulation, disability and environment need to be attended. Random blood sugar is done to exclude hypoglycaemia. Lumbar puncture needs to be done before the antivirals or any other treatment. ( if the possibility of increased intracranial pressure can be rule out) If it is not safe to do the LP blood culture is done and anti virals are started as soon as possible without delay. Immediate management
This is particularly important if the patient presents with confusion and drowsiness. Airway, breathing, circulation, disability and environment need to be attended. Random blood sugar is done to exclude hypoglycaemia. Lumbar puncture needs to be done before the antivirals or any other treatment. ( if the possibility of increased intracranial pressure can be rule out) If it is not safe to do the LP blood culture is done and anti virals are started as soon as possible without delay.
Supportive management Antipyretics, (acetaminophen), and antiemetics, (promethazine) may be given. Hydration should be checked due to the possibility of syndrome of inappropriate Antidiuretic hormone, and transient renal insufficiency caused by antiviral therapy, Provide of adequate hydration with 2/3 of maintenance is preferable. Monitoring of the vital parameters should be done during the initial period. Supportive management
Antipyretics, (acetaminophen), and antiemetics, (promethazine) may be given. Hydration should be checked due to the possibility of syndrome of inappropriate Antidiuretic hormone, and transient renal insufficiency caused by antiviral therapy, Provide of adequate hydration with 2/3 of maintenance is preferable. Monitoring of the vital parameters should be done during the initial period.
Management of the complications If there are seizures, anticonvulsants should be continued and close follow-up should be done. If there is of rapidly increasing intracranial pressure with clinical deterioration where medical treatment failed, surgical decompression has to be considered as a life saving measure. Ventriculoperitoneal (VP) shunt is placed for the symptomatic improvement in hydrocephalus. Management of the complications
If there are seizures, anticonvulsants should be continued and close follow-up should be done. If there is of rapidly increasing intracranial pressure with clinical deterioration where medical treatment failed, surgical decompression has to be considered as a life saving measure. Ventriculoperitoneal (VP) shunt is placed for the symptomatic improvement in hydrocephalus.
Follow up As they are vulnerable for complications such as hearing loss, vision problems, growth retardation, learning disability they need to be followed up with hearing, vision and growth assessment. Follow up
As they are vulnerable for complications such as hearing loss, vision problems, growth retardation, learning disability they need to be followed up with hearing, vision and growth assessment.
Vaccination Acute encephalitis has declined substantially due to the introduction of vaccines. MMR vaccination programmes eradicated measles-, mumps- and rubella-associated encephalitides. JE vaccinations have been used to control JE associated encephalitis. Vaccination
Acute encephalitis has declined substantially due to the introduction of vaccines. MMR vaccination programmes eradicated measles-, mumps- and rubella-associated encephalitides. JE vaccinations have been used to control JE associated encephalitis.

Management - Specific

Fact Explanation
Acyclovir If the features are suggestive of of encephalitis, acyclovir, 10 mg/kg three times daily, is added as soon as possible and once the diagnosis is confirmed acyclovir is continued for 14 days. This has shown to reduce the mortality and morbidity significantly. Acyclovir
If the features are suggestive of of encephalitis, acyclovir, 10 mg/kg three times daily, is added as soon as possible and once the diagnosis is confirmed acyclovir is continued for 14 days. This has shown to reduce the mortality and morbidity significantly.
Steroids Steroids eg:- Dexamethasone (4 mg every six hours)is given to reduce the inflammatory response occur during the anti microbial treatment. Steroids
Steroids eg:- Dexamethasone (4 mg every six hours)is given to reduce the inflammatory response occur during the anti microbial treatment.

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  1. BANATVALA JANGU E. Herpes simplex encephalitis. The Lancet Infectious Diseases [online] 2011 February, 11(2):80-81 [viewed 16 August 2014] Available from: doi:10.1016/S1473-3099(11)70012-3
  2. BRACKENRIDGE A, WALLBANK H, LAWRENSON RA, RUSSELL‐JONES D. Emergency management of diabetes and hypoglycaemia Emerg Med J [online] 2006 Mar, 23(3):183-185 [viewed 18 September 2014] Available from: doi:10.1136/emj.2005.026252
  3. BROWN L, SHAW T, WITTLAKE W. Does leucocytosis identify bacterial infections in febrile neonates presenting to the emergency department? Emerg Med J [online] 2005 Apr, 22(4):256-259 [viewed 18 September 2014] Available from: doi:10.1136/emj.2003.010850
  4. COREN M, BUCHDAHL R, COWAN F, RICHES P, MILES K, THOMPSON E. Imaging and laboratory investigation in herpes simplex encephalitis J Neurol Neurosurg Psychiatry [online] 1999 Aug, 67(2):243-245 [viewed 16 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1736500
  5. DAROUGAR S, WISHART MS, VISWALINGAM ND. Epidemiological and clinical features of primary herpes simplex virus ocular infection. Br J Ophthalmol [online] 1985 Jan, 69(1):2-6 [viewed 18 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1040512
  6. ELWIR SM, SHAFFER CC, ARVAN SW, KUPERMAN EF. Disseminated Varicella Zoster Virus Infection with Encephalitis in a UC Patient Receiving Infliximab Gastroenterol Hepatol (N Y) [online] 2013 Jan, 9(1):54-56 [viewed 18 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3975981
  7. FLORANCE NR, DAVIS RL, LAM C, SZPERKA C, ZHOU L, AHMAD S, CAMPEN CJ, MOSS H, PETER N, GLEICHMAN AJ, GLASER CA, LYNCH DR, ROSENFELD MR, DALMAU J. Anti-N-Methyl-D-Aspartate Receptor (NMDAR) Encephalitis in Children and Adolescents Ann Neurol [online] 2009 Jul, 66(1):11-18 [viewed 01 September 2014] Available from: doi:10.1002/ana.21756
  8. FORD-JONES EL, MACGREGOR D, RICHARDSON S, JAMIESON F, BLASER S, ARTSOB H. Acute childhood encephalitis and meningoencephalitis: Diagnosis and management Paediatr Child Health [online] 1998, 3(1):33-40 [viewed 18 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851260
  9. HAGE JE, CUNHA BA. Are ESR/CRP ratios helpful in differentiating West Nile encephalitis from non-West Nile virus meningitis/encephalitis? Scand J Infect Dis [online] 2013 Aug, 45(8):652-4 [viewed 18 September 2014] Available from: doi:10.3109/00365548.2013.768355
  10. JMOR FIDAN, EMSLEY HEDLEY CA, FISCHER MARC, SOLOMON TOM, LEWTHWAITE PENNY. The incidence of acute encephalitis syndrome in Western industrialised and tropical countries. Array [online] 2008 December [viewed 16 August 2014] Available from: doi:10.1186/1743-422X-5-134
  11. KENNEDY P. VIRAL ENCEPHALITIS: CAUSES, DIFFERENTIAL DIAGNOSIS, AND MANAGEMENT J Neurol Neurosurg Psychiatry [online] 2004 Mar, 75(Suppl 1):i10-i15 [viewed 11 August 2014] Available from: doi:10.1136/jnnp.2003.034280
  12. LIDOVE O, CHAUVEHEID M, BENOIST L, ALEXANDRA J, KLEIN I, PAPO T. Chronic meningitis and thalamic involvement in a woman: Fabry disease expanding phenotype J Neurol Neurosurg Psychiatry [online] 2007 Sep, 78(9):1007 [viewed 11 August 2014] Available from: doi:10.1136/jnnp.2006.108464
  13. MEHNDIRATTA M, NAYAK R, GARG H, KUMAR M, PANDEY S. Appraisal of Kernig's and Brudzinski's sign in meningitis Ann Indian Acad Neurol [online] 2012, 15(4):287-288 [viewed 11 August 2014] Available from: doi:10.4103/0972-2327.104337
  14. MOHANASUNDARAM K, NARAYANAN S, KUMARASAMY S. Bilateral Thalamic Hyperintensities in a case of Viral Encephalitis J Glob Infect Dis [online] 2010, 2(3):310-311 [viewed 16 August 2014] Available from: doi:10.4103/0974-777X.68541
  15. MYERS JJ, MODICA C, DUFOUR MS, BERNSTEIN C, MCNAMARA K. Routine Rapid HIV Screening in Six Community Health Centers Serving Populations at Risk J Gen Intern Med [online] 2009 Dec, 24(12):1269-1274 [viewed 18 September 2014] Available from: doi:10.1007/s11606-009-1070-1
  16. PILLAI BP, UNNIKRISHNAN AG, PAVITHRAN PV. Syndrome of inappropriate antidiuretic hormone secretion: Revisiting a classical endocrine disorder Indian J Endocrinol Metab [online] 2011 Sep, 15(Suppl3):S208-S215 [viewed 18 September 2014] Available from: doi:10.4103/2230-8210.84870
  17. RAYAMAJHI A, ANSARI I, LEDGER E, BISTA KP, IMPOINVIL DE, NIGHTINGALE S, BC RK, MAHASETH C, SOLOMON T, GRIFFITHS MJ. Clinical and prognostic features among children with acute encephalitis syndrome in Nepal; a retrospective study BMC Infect Dis [online] :294 [viewed 18 September 2014] Available from: doi:10.1186/1471-2334-11-294
  18. RUDKIN AK, WILCOX RA, SLEE M, KUPA A, THYAGARAJAN D. Relapsing encephalopathy with headache: an unusual presentation of isolated intracranial neurosarcoidosis J Neurol Neurosurg Psychiatry [online] 2007 Jul, 78(7):770-771 [viewed 18 September 2014] Available from: doi:10.1136/jnnp.2006.104703
  19. SPULER A, BLASZYK H, PARISI JE, DAVIS DH. Herpes simplex encephalitis after brain surgery: case report and review of the literature. J Neurol Neurosurg Psychiatry [online] 1999 Aug, 67(2):239-42 [viewed 16 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/10407001
  20. VERWEIJ PE, BRINKMAN K, KREMER HP, KULLBERG BJ, MEIS JF. Aspergillus Meningitis: Diagnosis by Non-Culture-Based Microbiological Methods and Management J Clin Microbiol [online] 1999 Apr, 37(4):1186-1189 [viewed 11 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC88672
  21. VITALIANI R, MASON W, ANCES B, ZWERDLING T, JIANG Z, DALMAU J. Paraneoplastic Encephalitis, Psychiatric Symptoms, and Hypoventilation in Ovarian Teratoma Ann Neurol [online] 2005 Oct, 58(4):594-604 [viewed 16 August 2014] Available from: doi:10.1002/ana.20614