Dermatology & Flora (by Dr. Vaseem Zamair)
Epithelium – made of Keratinized, Stratified, Squamous cells
Every cell has 3 sides: APICAL – upper, LATERAL –side, BASAL –inner or lower part.
Apical domains have cilia, villus and microvilli on them
Lateral Domains have different type of junctions which help either to attach to other cell or not to let anything pass thru it
- Zona occludens – tight junction which doesn’t let any thing to pass thru it – Virus and bacteria damaging zona occludens are Clostridium and Helicobacter Pylori.
- Zona Adherence – intermediate junction
- Macula adherence – Stick buttons like dics – which are called desmosomes. Antibodies against its own desmosomes make Pemphigus Vulgaris –à multiple blisters form
- Gap Junctions – it is the real connection between 2 adjacent cells where cytoplasms are interconnected… but this Gap-junctions closes if there is increase in Calcium or Potassium
Basal Domain – it has
Zona Lucida – Integrins, lemanins, Enactins
Zona Densa – collagen 4, Fibronectin both make Basal lamina
Lamina reticularis – collagen 7 and reticularis with collagen 3
Cellulitis can be caused by normal skin flora or by exogenous bacteria, and often occurs where the skin has previously been broken: cracks in the skin, cuts, blisters, burns, insect bites, surgical wounds, or sites of intravenous catheter insertion (Red, Warmth and Pain).
Panniculitis – involve fat around the inflamation.
Oomphalitis – surround the belly button ( in new borns).
Carbuncle – when it is boil, firm and indurated.
Furuncle – if hair follicle is involved.
Folliculitis – if pus at base of hair follicle & it proliferates to other hair follicles.
Fasciitis – when fascia is involved (pain during movement) *
Skin and Mucosal surfaces most common NORMAL FLORA
Aerobic = who are exposed to Oxygen (most of Gram+)
Anaerobic = who hide from Oxygen (can be both)
Gram- (negative) = who dwell in places which are not exposed to high concentration of Oxygen (can be called facultative too).
SKIN ( mostly aerobic and gram+ )
- Staph. Aureus à most common in all skin diseases & rash
- Staph. Epidermitis à present in deep surfaces of skin ( deep skin infections, I.V. lines, shunts passed etc)
3. Strep. Pyogenes à special types of rash ie.
a. Honey crusted lesions – Impetigo
b. Sand paper rash which includes palm & soles with Strawbery tongue – Scarlet fever
c. Necrotizing fasciitis – deep fascia is involved
d. Lymphangitis – RED STREAK on lymphatic chanel area (since strep. Travels thru lymph chanels)
e. Erysepelas – infection of SUB-CUTANEOUS FAT, doesnot blanch and is with raised borders of rash.
4. Propionobact. Acne à gram+ and anaerobic, dwelling in hair follicle loves oil – propionic acid. Therefore increase of progesterone levels always cause acne (during teenage years in Males and every month is females).
5. Staph. Saprophyticus à most commonly present in females and causes urinary tract infection as easily ascend through vagina.
4. and 5. hide from Oxygen à Anerobic (produce GAS *)
I. Nose – Staph. Aureus
II. Throat – Strep. Pyogenes
III. back of Throat :
- Strep. Pneumococcus: gram+
- Hemophi. Influenza
- Nisseria all types
IV. Beneath Gums and teeth : hide from Oxygen, therefore ANEROBIC àproduce Gas*
- Strep. Viridans
- strep. Mutans
- strep. Sangris
- strep. Salivaris
often called the gonococcus, causes the second most commonly transmitted sexual disease, gonorrhea (chlamydial infections are slightly more common).
Virulence factors of the gonococcus include:
1) Pili: Neisseria gonorrhoeae has complex genes coding for their pili. These genes undergo multiple recombinations, resulting in the production of pili with hypervariable amino acid sequences. These changing antigens in the pili protect the bacteria from our antibodies, as well as from vaccines aimed at producing antibodies directed against the pili
2) Protein II: This outer membrane protein is also involved in adherence to host cells.
Gonococcal Disease in Men
A man who has unprotected sex with an infected person can acquire a Neisseria gonorrhoeae infection. This organism penetrates the mucous membranes of the urethra, causing inflammation of the urethra (urethritis). Although some men will remain asymptomatic, most will complain of painful urination along with a purulent urethral discharge (pus can be expressed from the tip of the penis). Both asymptomatic and symptomatic men can pass this infection to another sexual partner. Possible complications of this infection include epididymitis, prostatitis, and urethral strictures. Fortunately, this disease is easily cured by a small dose of ceftriaxone.
Gonococcal Disease in Women
Like men, women can also develop a gonococcal urethritis, with painful burning on urination and purulent discharge from the urethra. However, urethritis in women is more likely to be asymptomatic with minimal urethral discharge. Neisseria gonorrhoeae also infects the columnar epithelium of the cervix, which becomes reddened and friable, with a purulent exudate. A large percentage of women are asymptomatic. If symptoms do develop, the woman may complain of lower abdominal discomfort, pain with sexual intercourse (dyspareunia), and a purulent vaginal discharge. Both asymptomatic and symptomatic women can transmit this infection. A gonococcal infection of the cervix can progress to pelvic inflammatory disease (PID, or “pus in dere”). PID is an infection of the uterus (endometritis), fallopian tubes (salpingitis), and/or ovaries (oophoritis).
Clinically, patients can present with fever, lower abdominal pain, abnormal menstrual bleeding, and cervical motion tenderness (pain when the cervix is moved by the doctor’s examining finger). Menstruation allows the bacteria to spread from the cervix to the upper genital tract. It is therefore not surprising that over 50% of cases of PID occur within one week of the onset of menstruation. The presence of an intrauterine device (IUD) increases the risk of a cervical gonococcal infection progressing to PID. Chlamydia
trachomatis is the other major cause of PID
Complications of PID include:
1) Sterility: The risk of sterility appears to increase with each gonorrhea infection. Sterility is most commonly caused by scarring of the fallopian tubes, whichoccludes the lumen and prevents sperm from reaching the ovulated egg.
2) Ectopic pregnancy: The risk of a fetus developing at a site other than the uterus is significantly increased with previous fallopian tube inflammation (salpingitis). The fallopian tubes are the most common site for an ectopic pregnancy. Again, with scarring down of the fallopian tubes, there is resistance to normal egg transit down the tubes.
3) Abscesses may develop in the fallopian tubes, ovaries, or peritoneum.
4) Peritonitis: Bacteria may spread from ovaries and fallopian tubes to infect the peritoneal fluid .
5) Peri-hepatitis (Fitz-Hugh-Curtis syndrome): This is an infection by Neisseria gonorrhoeae of the capsule that surrounds the liver. A patient will complain of right upper quadrant pain and tenderness. This syndrome may also follow chlamydial pelvic inflammatory disease.
Diagnosis and Treatment:
Diagnosis of Neisseria gonorrhoeae infection is best made by Gram stain and culture on Thayer-Martin VCN medium. Pus can be removed from the urethra by inserting a thin sterile swab. When this is Gram stained and examined under the microscope, the tiny dough-nut shaped diplococci can be seen within the white blood cells. In the past, the combination of penicillin G with probenicid was the regimen of choice. However, there arose penicillinase-producing gonococcal strains and now an even tougher strain, with chromosomally mediated antibiotic resistance to many antibiotics, such as tetracycline, erythromycin, and trimethoprim) sulfamethoxazole. This resistance is mediated by a block in antibiotic penetration into the bacterial cell. The current therapy of choice is ceftriaxone, a third generation cephalosporin. Ceftriaxone will also treat syphilis. If the patient is allergic to cephalosporins, spectinomycin or ciprofloxacin can be used as an alternative. The patient should also be treated at the same time with doxycycline or azithromycin for Chlamydia trachomatis, because up to 50% of patients will be concurrently infected with this beta-lactam-resistant (ceftriaxone included) bacteria.