**2. Clinical interview**

The clinical interview can be divided into presenting complaint, history of presenting com‐ plaint, past medical history, family history, medication history and social history. Each part can give insight into the likelihood of encephalitis and the important signs to look for while performing the clinical examination.

#### **2.1. Personal history**

We commence by obtaining the basic demographic details of the patient, confirming you have the correct patient by verifying the name, age and sex of the patient. These basic details can also give some insight into aetiological agents of encephalitis as different aetiological agents have their own archetypes in transmission regarding age and sex.

#### **2.2. Chief complaint**

The onset of symptoms can give an indication of the aetiology of encephalitis; however the incubations period of the pathogens vary and overlap so it can be difficult to determine the aetiology from the onset of the symptoms (table 1).

Fever is a common complaint in encephalitis. Fever characteristics can be significantly different in various causes of encephalitis (table 2). However caution must be taken as fever is patho‐ gnomonic for various illnesses ranging from infections to autoimmune or even malignancy.


1. INCUBATION PERIOD OF DISEASE Epidemiology Review (1983) 5(1): 1-15. Oxford Journals

The third step in the process is an assessment of the circulatory system. This is a multidimen‐ sional assessment and many factors must be taken into account. As part of the circulatory assessment, examination of the extremities is undertaken to determine if they are warm or cool as a way of assessing perfusion. Next press the nail bed for 5 seconds and if the refill is less than 2 seconds the capillary refill time is normal[1]. Now position the patient at a 45 degree angle and observe the filling of the jugular vein. This is an indicator of the Jugular Venous

The clinician should then proceed to measure the blood pressure and auscultate the heart for murmurs; if an abnormality is suspected an ECG should be performed. After these vital steps are done the clinician should move to the lower extremities. The clinician should start with palpating the peripheral pulses; femoral, popliteal and posterior tibial artery as well as the arteries of the upper limbs. Examination of the calf muscles should also be undertaken for DVT[3]. IV access should be obtained as soon as possible if there are signs of haemodynamic

Assessment of disability is the last step of primary assessment. The AVPU score can be calculated or a calculation of the Glasgow coma scale. Pupillary light reflex and posturing can indicate if there is neurological damage and the severity of encephalitis. A measurement of

The clinical interview can be divided into presenting complaint, history of presenting com‐ plaint, past medical history, family history, medication history and social history. Each part can give insight into the likelihood of encephalitis and the important signs to look for while

We commence by obtaining the basic demographic details of the patient, confirming you have the correct patient by verifying the name, age and sex of the patient. These basic details can also give some insight into aetiological agents of encephalitis as different aetiological agents

The onset of symptoms can give an indication of the aetiology of encephalitis; however the incubations period of the pathogens vary and overlap so it can be difficult to determine the

Fever is a common complaint in encephalitis. Fever characteristics can be significantly different in various causes of encephalitis (table 2). However caution must be taken as fever is patho‐ gnomonic for various illnesses ranging from infections to autoimmune or even malignancy.

have their own archetypes in transmission regarding age and sex.

aetiology from the onset of the symptoms (table 1).

Pulse (JVP) and in a healthy person the filling should be less than 3cm[2].

capillary glucose can also be performed in this stage.

compromise.

4 Encephalitis

**2. Clinical interview**

**2.1. Personal history**

**2.2. Chief complaint**

performing the clinical examination.

2. Vector Competence of California Mosquitoes for West Nile virus : Laura B. Goddard,\* Amy E. Roth,\* William K. Reisen,\* and Thomas W. Scott\* :Emerg Infect Dis. 2002 December; 8(12): 1385–1391.

3. The Epidemiology of Japanese Encephalitis: Prospects for Prevention : David Vaughn, Charles Hoke : Oxford Journals Medicine Epidemiologic Reviews : Volume 14, Issue 1 : Pp. 197-221.

4. Epstein-Barr Virus-specific Serology in Immunologically Compromised Individuals1 : Werner Henle, and Gertrude Henle : Accepted March 6, 1981. : Cancer Res November 1981 41; 4222

5. Epidemiology of Mycoplasma pneumoniae Infection in Families : Hjordis M. Foy, MD; J. Thomas Grayston, MD; George E. Kenny, PhD; E. Russell Alexander, MD; Ruth McMahan, MN : JAMA. 1966; volume 197( number11): pages 859-866

6. The expanding spectrum of Bartonella infections: I. Bartonellosis and trench fever: BASS, JAMES W. MD; VINCENT, JUDY M. MD; PERSON, DONALD A. MD : Paediatric Infectious Disease Journal: January 1997 - Volume 16 - Issue 1 pp 2-10

**Table 1.** There is an overlap in the incubation period of the various aetiological agents of encephalitis.


1. Fever of Unknown Origin: Clinical Overview of Classic and Current Concepts: Burke A. Cunha, MD, MACP : Infectious Disease Clinic of North America 21 (2007) Pages 867–915.

2. Herpes simplex virus infection: Dr Richard WhitleyMD, Bernard Roizman ScD: the Lancet : volume 357: Issue 9267, May 12 2001, pages 1513-1518

3. West Nile virus fever :Lásiková S, Moravcová L, Pícha D, Horová B. : Epidemiol Mikrobiol Imunol. 2006 Apr;55(2): 59-62

4. Transplacental Infection with Japanese Encephalitis Virus : Dr. U. C. Chaturvedi, A. Mathur, A. Chandra, S. K. Das,

H. O. Tandon and U. K. Singh : Oxford Journals, Journal of Infectious Diseases : Volume 141, Issue 6 : Pp. 712-715

5. Tick-Borne Encephalitis : Uga Dumpis, Derrick Crook, and Jarmo Oksi : Oxford Journals , Clinical Infectious Diseases : Volume 28, Issue 4 : Pp. 882-890

**Table 2.** Fever characteristics of the various aetiological agents of encephalitis.

Cephalgia is another common symptom of encephalitis. The cerebellum, Dura Mater and bones of the skull are insensible to pain[4]. Cephalgia is usually due to vasculature or sinus pain so a differential diagnosis must be sought to eliminate other causes of cephalgia. A cognitive change within a patient requires further assessment. We need to consider if there are focal signs or if it a general deterioration of consciousness. There are no specific patterns of cognitive dysfunctions identified within any specific aetiological group nor are cognitive changes exclusive to encephalitis. Consequently a definitive diagnosis is required in such circumstances where the patient is obviously unstable and the clinician must determine a course of action to reach a diagnosis. This can be achieved by examination of the patient and thorough diagnostic tests. General cognitive changes[5] which can be encountered in an encephalitic patient would range from personality changes, mood disorders, amnestic disorders, hallucinations, and seizures.

**2.5. Medical history**

**2.6. Lifestyle history**

**3. Physical examination**

**3.1. General observation**

**3.2. Examination of the eye**

frequently reported in patients with syphilis[21].

below.

Medications can cause cognitive changes and fever so a medication history should be obtained to ensure that the symptoms are not due to a chemical disturbance. Prescription drugs, non-

The Clinical Management of the Patient with Encephalitis

http://dx.doi.org/10.5772/55171

7

Different continents have different common aetiological agents of encephalitis so a history of travel should be documented. If a person is inclined to an outdoor lifestyle this should also be taken into account as they are at a higher risk of being bitten by tics or mosquitos depending on their demographics. Seasons affect behaviour pattern for example mating pattern in

After performing the primary survey and the clinical interview, the secondary survey can be undertaken. Some manifestations of encephalitis, which may be encountered, are discussed

During general observation we can start by assessing the skin. Some etiological agents which can cause encephalitis also cause dermatological lesions. A prime example is the most common viral cause of encephalitis which is HSV, HSV also causes herpetic skin lesions[11], which should been noted and is a good means to reach a fast diagnosis. Other aetiological agents which may also have dermatological signs are EBV[12] in which jaundice and oral petechiae can be observed. A patient infected with WNV occasionally will display a rash[13]. Basciliar angiomatosis[14] a vascular lesion of the skin which can extend to other organs is described as a Chancre and it is a diagnostic sign of primary syphilis. Untreated syphilitic patients can

Many Etiological agents of Encephalitis can cause ocular symptoms. During a HSV infection the patient can develop keratoconjunctivits[16]. For a patient with an EBV infection a perior‐ bital oedema may be noted[17]. Chorioretinitis[18] is a rare sequelae of West Nile Virus, Being rather uncommon it should still be excluded. Ocular manifestations of Mycoplasma pneumo‐ niae infection other than conjunctivitis are uncommon[19]. The most frequent ocular mani‐ festation of bartonella is neuroretinitis which is usually unilateral[20]. Interstitial keratitis is

progress to encephalitis and observing skin changes can aid in diagnosis [15]

prescription drugs and even recreational drug use should be noted.

mosquitos, so the season should also be noted.

Seizures and status epilepticus are a major concern in a patient with encephalitis. Depending on the aetiological agent seizures can be very common. In HSE virus encephalitis eliptogenic centres are located in the temporal and frontal cortices[6]. A seizure in a patient with HSV encephalitis is an indication of a poorer prognosis. In JE encephalitis periods of seizures alternating to periods of altered consciousness are common, they are however not as common in WN encephalitis and Murray Valley encephalitis[7].

#### **2.3. Past medical history**

Past medical history can demonstrate key risk factors of the patient suffering from encephalitis. For example any conditions which would leave the patient with an immunodeficiency like HIV, cancer or even a primary immunodeficiency in patient exhibiting symptoms of encepha‐ litis would merit immediate diagnostic procedures. It is important to consider if the patient is up to date with their vaccinations. In an unvaccinated patient the most common cause of encephalitis would be due to a varicella virus[8]. The most common cause in a vaccinated patient is Herpes Simplex Virus[9] Others facts which need to be considered are a previous episode of fever as some causes of encephalitis have a pattern of remitting fever. It is also important to ask the patient is if they have any recollection of being bitten by mosquitoes or tics as this can indicate possible aetiological agents.

#### **2.4. Family history**

Primary immunodeficiency can predispose a patient to the risk of encephalitis as well as other infections. So if a history of immunodeficiency is obtained the patient should immediately commence treatment with immunglobulins[10].

An instance wherein family history is vital is if the aetiology of encephalitis is contagious and other members of the family experiences symptoms of an infection or has shown symptoms of encephalitis. This may be useful in reaching the diagnosis of encephalitis or even determin‐ ing the aetiology of encephalitis. However the expression of symptoms in any illness is highly variable amongst individuals and that is something which should be kept in mind.

### **2.5. Medical history**

Cephalgia is another common symptom of encephalitis. The cerebellum, Dura Mater and bones of the skull are insensible to pain[4]. Cephalgia is usually due to vasculature or sinus pain so a differential diagnosis must be sought to eliminate other causes of cephalgia. A cognitive change within a patient requires further assessment. We need to consider if there are focal signs or if it a general deterioration of consciousness. There are no specific patterns of cognitive dysfunctions identified within any specific aetiological group nor are cognitive changes exclusive to encephalitis. Consequently a definitive diagnosis is required in such circumstances where the patient is obviously unstable and the clinician must determine a course of action to reach a diagnosis. This can be achieved by examination of the patient and thorough diagnostic tests. General cognitive changes[5] which can be encountered in an encephalitic patient would range from personality changes, mood disorders, amnestic

Seizures and status epilepticus are a major concern in a patient with encephalitis. Depending on the aetiological agent seizures can be very common. In HSE virus encephalitis eliptogenic centres are located in the temporal and frontal cortices[6]. A seizure in a patient with HSV encephalitis is an indication of a poorer prognosis. In JE encephalitis periods of seizures alternating to periods of altered consciousness are common, they are however not as common

Past medical history can demonstrate key risk factors of the patient suffering from encephalitis. For example any conditions which would leave the patient with an immunodeficiency like HIV, cancer or even a primary immunodeficiency in patient exhibiting symptoms of encepha‐ litis would merit immediate diagnostic procedures. It is important to consider if the patient is up to date with their vaccinations. In an unvaccinated patient the most common cause of encephalitis would be due to a varicella virus[8]. The most common cause in a vaccinated patient is Herpes Simplex Virus[9] Others facts which need to be considered are a previous episode of fever as some causes of encephalitis have a pattern of remitting fever. It is also important to ask the patient is if they have any recollection of being bitten by mosquitoes or

Primary immunodeficiency can predispose a patient to the risk of encephalitis as well as other infections. So if a history of immunodeficiency is obtained the patient should immediately

An instance wherein family history is vital is if the aetiology of encephalitis is contagious and other members of the family experiences symptoms of an infection or has shown symptoms of encephalitis. This may be useful in reaching the diagnosis of encephalitis or even determin‐ ing the aetiology of encephalitis. However the expression of symptoms in any illness is highly

variable amongst individuals and that is something which should be kept in mind.

disorders, hallucinations, and seizures.

**2.3. Past medical history**

6 Encephalitis

**2.4. Family history**

in WN encephalitis and Murray Valley encephalitis[7].

tics as this can indicate possible aetiological agents.

commence treatment with immunglobulins[10].

Medications can cause cognitive changes and fever so a medication history should be obtained to ensure that the symptoms are not due to a chemical disturbance. Prescription drugs, nonprescription drugs and even recreational drug use should be noted.

#### **2.6. Lifestyle history**

Different continents have different common aetiological agents of encephalitis so a history of travel should be documented. If a person is inclined to an outdoor lifestyle this should also be taken into account as they are at a higher risk of being bitten by tics or mosquitos depending on their demographics. Seasons affect behaviour pattern for example mating pattern in mosquitos, so the season should also be noted.
