Module 5-Path Continued: Men, Salmonella

Question 1

What are the 4 different etiologies of Meningitis?

Answer 1

Bacterial
Viral
Fungal
Tuberculous

Question 2

What is meningitis ?

Answer 2

Inflammation of leptomeninges (pia and arachnoid)

Question 3

How is meningitis spread?

Answer 3

Via inhalation of respiratory droplets == colonizes in nasopharynx —- spreads directly to brain via sinuses to meninges but can also spread via blood (via thoracic duct into lymphatics to bloodstream to CSF)

Question 4

What are the symptoms of meningitis?

Answer 4

Headache, fever, stiff neck and photophobia

Question 5

What is the best investigation for meningitis?

Answer 5

Spinal Tap

Question 6

What examination should you do on a patient before spinal tapping the patient?

Answer 6

Fundoscopy to check for papilledema
if a patient has papilledema and you as the physician do a lumbar puncture the patient will get an uncal herniation (or transtentorial herniation)
CNIII is damage so patient pupil is dilated (mydriasis)

Question 7

What would you find in the CSF of a patient with bacterial meningitis?

Answer 7

Increased Protein
Decreased Glucose (Bacteria eats it)
Increased PMNs
CSF will also be cloudy due to pus – exudate

Question 8

What would you find in the CSF of a patient with viral meningitis?

Answer 8

Slightly Increased Protein
Slightly low/normal glucose
Increased lymphocytes (CD8 T cells –remember its viral thats why)

Question 9

What would you find in the CSF of a patient with fungal meningitis?

Answer 9

Increased protein
Slightly decreased glucose
Mix of PMNs and lymphocytes (remember acute and chronic cells for fungal)

Question 10

What would you find in the CSF of a patient with TB meningitis?

Answer 10

Increased Protein
Decreased Glucose
Increased CD4 T lymphocytes

Question 11

A neonate up to 2 months, what bacterial meningitis would you find?

Answer 11

Strep. Agalactiae (group B) (gram positive bacteria)

group B colonizes the vagina of a pregnant women so baby can get meningitis during birth in the birth canal.

Question 12

Infancy through childhood, what bacterial meningitis would you find?

Answer 12

Strep. Pneumoniae (gram positive bacteria, diplocci)

Question 13

In adolescences what bacterial meningitis would you find?

Answer 13

Neisseria meningitides (gram negative bacteria)

Question 14

During adulthood what bacterial meningitis would you find?

Answer 14

Strep Pneumoniae (gram positive bacteria, diplocci)

Question 15

on gross image of the brain of a patient with bacterial meningitis what do you find?

Answer 15

Hyperemic (increased active blood volume) blood vessels

purulent exudate in subarachnoid space

Question 16

What is one of the best investigations for TB?

Answer 16

Acid fast stain for CSF

Question 17

What is the first investigation for TB?

Answer 17

xray

Question 18

What is one complication to bacterial meningitis?

Answer 18

Gram negative septic shock (aka neisseria meningitides )

N. meningitides leads to gram negative septic shock from meningococcal septicemia

Question 19

Meningococcal Septicemia can lead to DIC how?

Answer 19

LPS binds to LBP and this complex is now taken up by macrophages , secrete —- TNFalpha, recruits —– neutrophils, secrete —- IL-1 and procoagulant which causes endothelial damage —– systemic microthrombi —- DIC

Question 20

How does a gram positive bacteria cause DIC?

Answer 20

Via superantigens

Question 21

What are the internal and external bleeding spots in DIC?

Answer 21

Internal: adrenal glands hemorrhage
External: purpura and petechiae and ecchymosis
this leads to Waterhouse-Friderichsen Syndrome which can lead to Addison’s disease.

Question 22

What investigations would you do for Meningococcal Septicemia?

Answer 22

Increased D-dimer
Increased bleeding time
Increased PT and PTT

Question 23

So the first complication of Bacterial meningitis was meningococcal septicemia due to N. meningitides, what are the other 3 complications of bacterial meningitis?

Answer 23

2. Deafness
3. Communicating Hydrocephalus
4. Spread of infection can cause encephalitis (these patients are usually immunocompromised)

Question 24

Clostridium Perfringens is a gram positive bacilli, anaerobic bacteria that produces spores and is found in the soil and invades traumatic and surgical wounds. what type of infection does this bacterial cause?

Answer 24

Myonecrosis aka gas gangrene
gas forming organisms: degradative enzymes produce gas in tissues
Deadly form of gangrene –> medical emergency
Perfringens perforates a gangrenous leg

Question 25

Clostridium Perfringens secretes 12 exotoxins= necrosis | most important is alpha toxin (lecithinase) what exactly do these exotoxins do?

Answer 25

Degrade lecithin -- a major component cell membrane Destroys RBCs, platelets, muscle fibers (myonecrosis) Enzymes released from necrotic tissue

Question 26

Schistosoma is a parasite that has what significant effects on the body if contracted?

Answer 26

Bladder carcinoma hepatomegaly, fibrosis and portal HTN Eggs induce granulomas --> fibrosis and this leads to liver failure and hence ascites

Question 27

Staphylococci lesions can either be inflammatory mediate or toxin mediated. Name some inflammatory mediated examples:

Answer 27

1. Skin- folliculitis, furuncle, carbuncle, cellulitis, impetigo, paronychia, surgical wound infection 2. Post Partum-mastitis 3. Bacteremia 4. Endocarditis: tricupsid valve 5. Osteomyelitis 6. Pneumonia: bronchopneumonia, abscess wit hwatery pus 7. Bacteremic abscess- lung, kidney, brain 8. MRSA

Question 28

What are examples of toxin mediated staphylococci lesions?

Answer 28

1. Food poisoning: enterotxoin 2. Toxic Shock Syndrome (TSS)- intravaginal tampon if left in longer leads to growth of staph -- release of exotoxin into circulation ---rash, conjunctivitis and vomiting 3. Scaled skin Syndrome

Question 29

Neisseria gonorrhoeae is a gram negative, diplococci, sexually transmitted disease. What are the signs and symptoms in males, homosexual males and females?

Answer 29

Males: 1. Urethritis and Epididymitis --urethral discharge and dysuria Homosexual Males: 1. oropharyngitis and proctitis (inflammation of rectum) Females: 1. Cervicitis, salpingitis (infection/inflammation of fallopian tubes) and peritonitis, PID (pelvic inflammatory disease) --vaginal discharge, inter menstrual bleeding --if untreated can lead to scaring of the fallopian tubes

Question 30

Neisseria gonorrhoeae disseminated via what methods?

Answer 30

1. Rare via hematogenous (carried in blood) 2. Tenosynovitis (inflammation of the lining of sheath that surrounds tendon), arthritis 3. Hemorrhagic skin lesions 4. Endocarditis 5. Rarely meningitis

Question 31

Neisseria gonorrhoeae can occur in a newborn, explain the mechanism for this

Answer 31

``` infections acquired during passage of the fetus through cervix during labor purulent conjunctivitis (opthalmia neonatorum) use of erythomycin/silver nitrate eye drops after birth can prevent this ```

Question 32

How does one diagnosis Neisseria gonorrhoeae in males and females

Answer 32

Males: microscopy of exudate: PMNs and gram - diplococci Females: culture of exudate - essential b/c gram - diplococci are normal part of vaginal flora could yield false negative result if there are fewer organism

Question 33

What other STI can produce similar signs and symptoms as Neisseria gonorrhoeae?

Answer 33

Chlamydial infection

Question 34

Typhoid fever = Enteric Fever and it is caused by Salmonella Typhi: gram negative bacilli. how is this bacteria acquired?

Answer 34

Through ingestion of contaminated food, water (transferred in feces)

Question 35

Typhoid fever (Enteric fever) affects the body differently with each week, explain the effects of the bacteria during week one

Answer 35

Enter ileal wall (no lesions at this time) -- enter bloodstream --- bacteremia

Question 36

What is the effect of the salmonella typhi in week two?

Answer 36

Liver enlarged = typhoid nodules: composed of Kupffer cell hyperplasia --minute foci of hemorrhagic necrosis, collections of macrophages --Typhoid nodules: macrophages that contain bacteria, RBCs, degenerated lymphocytes Spleen: enlarged soft spleen with splenitis, typhoid nodules

Question 37

What is the effect of salmonella typhi in week three?

Answer 37

Bacteria excreted through gall bladder in bile -- lumen of gut --- re-enter gut wall through ileum --sensitization has occurred during this period --- contact with organisms produces lymphoid hypertrophy (increase lymph tissue) and necrosis in the mucosa

Question 38

What are the clinical features of Enteric/Typhoid fever?

Answer 38

- --Fever, toxic appearance, leukopenia (decreased WBCs) and bradycardia - --Endotoxin = depression of heart and bone marrow - --Ulcers heal without scarring - -Complications: perforation peritonitis bleed (3rd and 4th week)

Question 39

What are the lesions of enteric/typhoid fever?

Answer 39

ileum --- lymphoid hypertrophy (Peyer's patches), necrosis, ulceration - --no PMNs (Excrete a protein called invasion, that allows non phagocytic cells to take up the bacteria, where it is able to live intracelluarly; also inhibit oxidative burst of leukocytes = innate (Acute) immune response infected) - -only macrophages, erythrophagocytosis (phagocytosis of RBCs) - -mesenteric LN enlarged, hemorrhagic necrosis

Question 40

How would you diagnosis Enteric/Typhoid fever with each week?

Answer 40

End of week 1: blood culture -- lysis of macrophages release large number of bacilli into circulation Week 2: organisms in feces/ urine Week 3: Widal test (demonstrate antibodies ) --- bacteria are mixed with serum containing specific antibodies from an infected individual

Question 41

In some patients with Enteric/Typhoid fever, they develop chronic colonization of gallbladder, in what kind of patients does this develop?

Answer 41

Asymptomatic carries

Question 42

Gram negative bacteria septicemia leads to septic shock, what are some features of septic shock?

Answer 42

Common Clinical Situation Fever, septicemia, DIC, Shock Normally commensual organsims --- become pathogenic immune deficiency, break in mucous membranes