Differential Diagnosis

Von and Eman

DIFFERENTIAL DIAGNOSIS

1. Meningitis2. Encephalitis3. Epilepsy4. Febrile seizures

MENINGITIS

• Is an inflammation of the membranes (meninges) and cerebrospinal fluid surrounding the brain and spinal cord, usually due to the spread of an infection

• The swelling associated with meningitis often triggers the "hallmark" symptoms of this condition, including headache, fever and a stiff neck

• Most cases of meningitis are caused by a viral infection, but bacterial and fungal infections also can lead to meningitis– Bacterial infections are the most damaging,

identifying the source of the infection is an important part of developing a treatment plan

• Depending on the cause of the infection, meningitis can resolve on its own in a couple of weeks — or it can be a life-threatening emergency

• ACUTE BACTERIAL MENINGITIS– Usually occurs when bacteria enter the

bloodstream and migrate to the brain and spinal cord

– Can directly invade the meninges, as a result of an ear or sinus infection or a skull fracture

– Streptococcus pneumoniae (pneumococcus)• Most common cause of bacterial meningitis in infants

and young children in the United States.

– Neisseria meningitidis (meningococcus)• Another leading cause of bacterial meningitis • It commonly occurs when bacteria from an upper

respiratory infection enter your bloodstream.• Highly contagious and may cause local epidemics in

college dormitories and boarding schools and on military bases

– Haemophilus influenzae (haemophilus)• Before the 1990s, Haemophilus influenzae type b (Hib) bacterium

was the leading cause of bacterial meningitis. • Hib vaccines —routine childhood immunization

– Greatly reduced the number of cases of this type of meningitis

• It tends to follow an upper respiratory infection, ear infection (otitis media) or sinusitis

– Listeria monocytogenes (listeria)• These bacteria can be found almost anywhere — in soil, in dust and

in foods that have become contaminated– Soft cheeses, hot dogs and luncheon meats

• Most healthy people exposed to listeria don't become ill– Pregnant women, newborns and older adults tend to be more susceptible.

• Listeria can cross the placental barrier, and infections in late pregnancy may cause a baby to be stillborn or die shortly after birth

• Viral meningitis– Usually mild and often clears on its own within two weeks– A group of common viruses known as enteroviruses are responsible

for about 90 percent of viral meningitis in the United States– Most common signs and symptoms: Rash, sore throat, joint aches

and headache– “Worst headache I've ever had“

• Chronic meningitis– Ongoing (chronic) forms of meningitis occur when slow-growing

organisms invade the membranes and fluid surrounding the brain– Although acute meningitis strikes suddenly, chronic meningitis

develops over four weeks or more– Signs and symptoms: Headaches, fever, vomiting and mental

cloudiness– This type of meningitis is rare

• Fungal meningitis– Relatively uncommon – Cryptococcal meningitis

• Fungal form of the disease that affects people with immune deficiencies, such as AIDS

– Life-threatening if not treated with an antifungal medication

• Other meningitis causes– Meningitis can also result from noninfectious causes, such

as drug allergies, some types of cancer and inflammatory diseases such as lupus

Harrison’s Principles of Internal Medicine, 17th Edition

CASE

• II month old male infant• First onset and single episode of

generalized seizure• coughing with nasal catarrh for the

last 5 days• T = 38.9C• Perinatal and postnatal histories

were unremarkable• The father admitted to be having

the same episodes when he was still around 5 years old during the height of his fever

• Neurological examination was normal

MENINGITIS

•History of infection•Classic triad of fever, headache, and nuchal rigidity•(+) Kernig's sign and Brudzinski's sign•Decreased level of consciousness occurs in >75% of patients and can vary from lethargy to coma•Nausea, vomiting, and photophobia are also common complaints•Seizures•Raised ICP •Reduced level of consciousness, papilledema, dilated poorly reactive pupils

ENCEPHALITIS

• “Inflammation of the brain," it usually refers to brain inflammation resulting from a viral infection– Primary encephalitis

• Involves direct viral infection of the brain and spinal cord

– Secondary encephalitis• A viral infection first occurs elsewhere in the body and then travels

to the brain

• In contrast to viral meningitis, where the infectious process and associated inflammatory response are limited largely to the meninges, in encephalitis the brain parenchyma is also involved

• It can be caused by:– Bacterial infection

• Spreads directly to the brain (primary encephalitis)• Bacterial meningitis

– A complication of a current infectious disease • Syphilis (secondary encephalitis)

– Parasitic or protozoal infestations• Can also cause encephalitis in people with compromised immune

systems• Such as toxoplasmosis, malaria, or primary amoebic

meningoencephalitis

– Lyme disease and/or Bartonella henselae may also cause encephalitis

CASE

• II month old male infant• First onset and single episode of

generalized seizure• Coughing with nasal catarrh for the

last 5 days• T = 38.9C• Perinatal and postnatal histories

were unremarkable• The father admitted to be having

the same episodes when he was still around 5 years old during the height of his fever

• Neurological examination was normal

ENCEPHALITIS

• History of infection• Fever, headache and nuchal rigidity

• (+) Kernig’s and Brudzinski’s sign• Photophobia and seizures• Altered level of consciousness• Evidence of either focal or diffuse

neurologic signs and symptoms• Focal findings are aphasia,

ataxia, upper or lower motor neuron patterns of weakness, involuntary movements and cranial nerve deficits

• Hallucinations, agitation, personality change, behavioral disorders, and, at times, a frankly psychotic state

EPILEPSY

• Classified as a disorder of at least two unprovoked recurrent seizures

• More common in young and old, plateau at 2nd – 4th decades of life

• In children (0-14 years old)congenital> trauma=infection>CVA=tumor

• Genetic Predispostion– The direct result of a known or presumed genetic

defect in which seizures are the core symptom of the disorder• Examples include childhood absence epilepsy,

autosomal dominant nocturnal frontal lobe epilepsy, and Dravet syndrome

• Epileptic Seizures– No sexual predisposition, may occur at any age– Loss of consciousness is common– Onset is usually abrupt and may have a short aura– Vocalization is present during automatism

Dravet’s Syndrome• Severe myoclonic epilepsy of infancy (SMEI) • Generalized epilepsy syndrome • Onset is in the first year of life • Peaks at about 5 months of age with febrile

hemiclonic or generalized status epilepticus • Boys are twice as often affected as girls• Prognosis is poor

• Most cases are sporadic• Family history of epilepsy and febrile

convulsions is present in around 25 percent of the cases

• Known causative genes are the sodium channel α subunit genes SCN1A and SCN2A, an associated β subunit SCN1B, and a GABAA receptor γ subunit gene, GABRG2

PathophysiologySeizure Generation

Cellular Level

Na+ channels

Increase Influx of Na+

Increase

intracellular Na+ and

water

Increase Tissue

excitability

Cations

Ca2+ channels

K+ channels

Decrease intracellula

r K+

Cell hyperexcit

ability

Firing of thalamic and

cortical neurons

Synaptic Level

GABA

Decreased

Glutamate

Increased

Hyperexcitable state

CASE•II month old male infant•First onset and single episode of generalized seizure•Coughing with nasal catarrh for the last 5 days•T = 38.9C•Perinatal and postnatal histories were unremarkable•The father admitted to be having the same episodes when he was still around 5 years old during the height of his fever•Neurological examination was normal

DRAVET’S SYNDROME

•Onset is in the 1st year of life•Peaks at about 5 months of age with febrile hemiclonic or generalized status epilepticus

•Boys are twice as often affected as girls•(+)Family History

FEBRILE SEIZURES

• Fever fit or febrile convulsion, is a convulsion triggered by a rise in body temperature

• The direct cause of a febrile seizure is not known– It is normally precipitated by a recent upper

respiratory infection or gastroenteritis• A febrile seizure is the effect of a sudden rise in

temperature (>39°C/102°F) rather than a fever that has been present for a prolonged length of time

• Simple febrile seizure – Seizure lasts less than 15 minutes, does not recur

in 24 hours, and involves the entire body (classically a generalized tonic-clonic seizure)

• Complex febrile seizure– Characterized by longer duration, recurrence, or

focus on only part of the body

• The simple seizure represents the majority of cases and is considered to be less of a cause for concern than the complex– Simple febrile seizures generally do not cause

permanent brain injury– Prognosis after a simple febrile seizure is excellent,

whereas an increased risk of death has been shown for complex febrile seizures, partly related to underlying conditions

CASE•II month old male infant•First onset and single episode of generalized seizure•Coughing with nasal catarrh for the last 5 days•T = 38.9C•Perinatal and postnatal histories were unremarkable•The father admitted to be having the same episodes when he was still around 5 years old during the height of his fever•Neurological examination was normal

FEBRILE SEIZURES

•History of infection•Ages of 3 months and 5 years•Twice more common in boys than girls•Fever and seizures•(paki dagdagan na lang, wala kasi ako nelson’s dito…)

REFERENCES

• Harrison’s Principle of Internal Medicine, 17th edition

• http://www.ilae-epilepsy.org/Visitors/About_ILAE/Index.cfm

• http://www3.interscience.wiley.com/journal/118734154/abstract

• http://www.ninds.nih.gov/disorders/epilepsy/epilepsy.htm

• http://www.epilepsyfoundation.org/about/types/causes/genetics.cfm