Diseases of the Nervous System and Eyes

Question 1

Subarachnoid Space

Answer 1

filled with cerebrospinal fluid; compartment in between arachnoid and pia maters

Question 2

Cranial Meminges

Answer 2

Dura mater
Arachnoid mater
Pia mater

Question 3

Portals of Entry

Answer 3

CNS: breaks in bones or meninges
penetration of the Blood-brain barrier

eyes: breaks

Question 4

Bacterial Meningitis Symptoms

Answer 4

high cerebrospinal leukocyte count
high fever
inflammation of the meninges (outer layer of brain)
-sharp headache, vomiting, neck pain and stiffness, loss of brain functions (drowsiness and confusion)
progression of the encephalitis (infection of brain)
-deafness, blindness, behavioral changes, coma and death

Question 5

Meningococcal Meningitis

Answer 5

causative agent: Neisseria meningitidis
Gram-negative diplococci

teenagers and adults over 50 have the highest risk of death
can kill within the first 6 hours of having symptoms

symptoms: normal meningitis symptoms plus pinpoint red rash (petechiae)

complications: brain damage
shock
increased spinal fluid pressure
myocarditis (inflammation of the heart)
hydro cephalitis (blockage of spinal fluid in brain)
deafness
paralysis of various muscle
intellectual disabilities

Dx: CSF examination
culture

Treatment: IV antibiotics

Question 6

Pneumococcal Meningitis

Answer 6

causative agent: Streptococcus pneumoniae

most common cause of meningitis in adults and second most common in children older than 6 years of age

symptoms:
standard meningitis symptoms

prevention: early treatment of pneumonia and ear infections caused by pneumococcus may decrease the risk of meningitis;
there are two effective vaccines on the market to prevent pneumococcus infection
the current recommendations are for people at high risk for pneumonia (children and everyone over the age of 55) to be vaccinated

treatment: IV antibiotics

prognosis: with early treatment, outcome is better;
however, 20% of those who contract this disease will die of it and 50% will have serious long-term complications

Question 7

Haemophilus influenzae: meningitis

Answer 7

children under 5 years of age
(most frequently in 1 month up to 4 years w/ a peak at 6 to 9 months)
spreads from the respiratory tract to bloodstream to meninges

once the leading cause of meningitis, but Hib vaccine has drastically reduced incidence

symptoms: standard meningitis symptoms

complications: roughly 20% may experience some hearing loss
some patients will have brain damage, which can include seizures, learning disorders, abnormalities in speech and language development, and behavioral problems

Question 8

Leprsosy

Answer 8

causative agent: Mycobacterium leprae
related to TB; intracellular pathogen

pathology: development of multiple lesions on the skin
body’s cell mediated response destroys the nerve endings
loss of sensory perception on areas of skin that have been infected - tends to be areas that are cooler than body temperature
insensitive areas easily become infected w/ secondary infections

treatment: BCG: vaccine for TB, preventative for leprosy

Question 9

Tetanus

Answer 9

causative agent: Clostridium tetani

pathology: infection begins when the spores are introduced into injury or wound;
spores germinate, releasing active bacteria that reproduce and produce a neurotoxin (tetanospasmin)
it selectively blocks inhibitory nerve transmission (GABA release) from the spinal cord to the muscles, allowing the muscles to go into severe spasm

symptoms: spasms and tightening of the jaw muscles
neck and other muscles
chest muscles
abdominal muscles
back muscles (often causing arching (opisthotonosis))
tetanic seizures (painful, powerful bursts of muscle contraction)
irritability
fever

Dx: symptoms

treatment: control and reverse the tetani w/ antitoxin, vaccine and antibiotics

Question 10

Botulism

Answer 10

signs and symptoms: flaccid paralysis (muscle weakness); muscle paralysis that starts w/ eye muscles; no fever; usual cause of death is respiratory paralysis; many cases are subclinical

Dx: brain scan
spinal fluid examination
nerve and muscle function tests (nerve conduction study (NCS) and electromyography (EMG))
tensilon test: for myasthenia gravis

causative agent: Clostridium botulinum
G+ bacillus, endospore former, strict anaerobe, toxin
food-borne infections, especially honey
Botulinum toxin blocks the normal acetylcholine messages between muscles and nerves

treatment : antitoxin
wound (botulism): removal and antibiotics plus antitoxin

Question 11

Rabies

Answer 11

causative agent: rabies virus

slow, progressive disease characterized by fatal encephalitis (cerebrum, meninges, cerebellum, and brainstem)

incubation time: 1-2 months

symptoms: headache, fever, nausea
partial paralysis near the bite site (persist for 2 to 10 days, then worsen); paralysis then becomes more general
throat muscles undergo painful spasms
confusion and hallucinations occur
10-14 days after onset, patient goes into a coma and dies

Dx: observation on Negrii bodies (cytoplasmic inclusion bodies found in neurons: virus replication occurs)

Question 12

Trachoma

Answer 12

roughening of the inner surface of the eyelids

causative agent: Chlamydia trachomatis
G-; anaerobic

symptoms: eye discharge
swollen eyelids
trichiasis (turned-in eyelashes) at least one eyelash rubs on eyeball
swelling of lymph nodes in front of the ear
seeing bright lights
increased heart rate
further ear, nose and throat complications
trachomatous scarring (TS): scarring in the tarsal conjunctiva
corneal opacity (CO)

treatment: Azithromycin (single oral dose of 20mg/kg) or tropical tetracycline (1%)
refer for eyelid surgery

Question 13

Bacterial Conjunctivitis

Answer 13

bacterial conjunctivitis is extremely contagious!

causative agents: S. aureus
S. pyogenes
Haemophilus influenzae
Pseudomonas sp.
Neisseria gonorrhoeae

symptoms: dilated blood vessels
swollen eyelids
a stingy, grey or yellowish discharge

treatment: antibiotic eye drops