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Gonorrhea: Signs, Symptoms & Diagnosis

by John Fisher, MD
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    00:01 Now as far as the clinical features of gonorrhea go, this organism is notorious for producing very, very severe dysuria.

    00:14 Urination is extremely painful.

    00:18 It would be very unusual if gonorrhea were totally asymptomatic.

    00:23 It's possible but very unusual.

    00:28 The urethral discharge may start out as scant and mucoid.

    00:33 But within 1 to 2 days, it is frank pus.

    00:37 Interestingly enough, in contrast to urinary tract infections, there's not the urgency to urinate, and urinary frequency is not common, like it is in a urinary tract infection.

    00:55 If patients don't seek treatment, this syndrome will resolve in several weeks.

    01:05 And this cartoon shows what these organisms look like under the microscope.

    01:12 You notice that they are inside of neutrophils.

    01:16 And they are diplococci, pairs of cocci.

    01:21 And the other thing to notice is that the flat sides of these cocci are apposed.

    01:27 They are not end to end like in Streptococcus pneumoniae.

    01:32 So biscuit-shaped diplococci, notably inside of neutrophils.

    01:42 Now to prove that a patient has gonorrhea versus non-gonococcal urethritis, you would want to culture the discharge and Gram-stain the discharge.

    01:57 The typical culture media is a media known as Thayer-Martin medium.

    02:06 Thayer-Martin is nothing more than chocolate agar, which will grow many, many organisms, and supplies hemin and nicotinamide adenine dinucleotide to fastidious organisms.

    02:19 So many things will grow on Thayer-Martin media, but we're only interested in isolating Neisseria gonorrhoeae.

    02:30 So how do we get rid of the other organisms that might grow? Well, what we would do is we put antibiotics into the medium.

    02:39 For example, we put vancomycin and you may know that vancomycin is broad spectrum for Gram-positive organisms.

    02:49 So therefore, no Gram-positives should grow on Thayer-Martin.

    02:54 The other thing in Thayer-Martin is colistin.

    02:58 Colistin is a broad spectrum, Gram-negative antibiotic.

    03:03 In other words, for Gram-negative rods like E. coli, like pseudomonas, and other things that may tend to grow.

    03:13 But those won't grow with colistin added to thayer-martin media.

    03:18 And finally, nystatin which is an antifungal agent will keep the growth of yeast and other fungi away.

    03:29 And so therefore, Thayer-Martin media is a highly selective media.

    03:36 In general, you use Thayer-Martin only for Neisseria gonorrhoeae.

    03:42 There are other things you would use chocolate agar for but for Thayer-Martin, it's gonorrhea.

    03:50 Now as far as the Gram-stained smears, we've already discussed that they're Gram-negative intracellular diplococci.

    04:00 In contrast, this particular view with the cartoon shown.

    04:05 But I think you can still see the these are flat sides apposed Gram-negative diplococci.

    04:13 And the Gram stain is very, very sensitive in symptomatic men.

    04:21 In other words, Gram-stain that discharge and you should be able to find these organisms.

    04:28 However, if the unusual scenario obtains that the man is asymptomatic, then the Gram stain is only 50% sensitive.

    04:43 What is now being used in many laboratories, instead of culture is something called the nucleic acid amplification test.

    04:56 This has largely replaced cultures for screening, especially in asymptomatic genital infections.

    05:05 And the test is able to detect not only Neisseria gonorrhoeae, but it's often combined to detect Chlamydia trachomatis.

    05:19 However, it is not more sensitive than a regular culture.

    05:26 It just depends upon the facilities that the laboratory has.

    05:31 However, it is very, very sensitive for Chlamydia trachomatis and culturing Chlamydia trachomatis is cumbersome and not used widely.

    05:45 But the bottomline is that all patients with urethritis should be tested for both Neisseria gonorrhoeae and Chlamydia trachomatis.


    About the Lecture

    The lecture Gonorrhea: Signs, Symptoms & Diagnosis by John Fisher, MD is from the course Genital and Sexually Transmitted Infections. It contains the following chapters:

    • Gonorrhea – Signs/Symptoms
    • Gonorrhea – Diagnosis

    Included Quiz Questions

    1. Intracellular gram negative dipplococci.
    2. Extracelluar gram negative dipplococci.
    3. Intracellular gram positive cocci in chains.
    4. Extracellular gram positive dipplococci.
    5. Extracellular gram negative aggregates of cocci.
    1. Chocolate agar with vancomycin, cholistin, and nystatin
    2. Simple chocolate agar
    3. MacConkey agar
    4. Lactose agar with vancomycin and nystatin
    5. Chocolate agar with nystatin
    1. It is a good test for identifying both gonorrhea and chlamydia type urethritis.
    2. It is very sensitive for chlamydia, but a poor test for gonorrhea.
    3. It is a better test for isolating Neisseria gonorrhea than culturing.
    4. It is very sensitive for N. gonorrhea, but not a good test for identifying C. trachomatis.
    5. Culturing for chlamydia and gonorrhea is the better option over NAAT.

    Author of lecture Gonorrhea: Signs, Symptoms & Diagnosis

     John Fisher, MD

    John Fisher, MD


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