Unmasking Syphilis: stages, diagnosis, treatment and prevention

 

Introduction to syphilis

Syphilis is a sexually transmitted infection caused by the bacterium treponema pallidum subspecies pallidum. The signs and symptoms of vary depending in which of the four stages It presents (primary, secondary, latent, and tertiary). Syphilis is caused by a spirochete bacterium treponema. Microscopically treponema pallidum appears as fine, spiral (8 to 24 coils). They are not cultivatable with any consistency in artificial laboratory media outside the host. T. pallidum are extremely susceptible to a variety of physical and chemical agents. However, they may remain viable for up to 5 days in tissue specimens removed from diseased animals and from frozen specimen. The most common mode of transmission is through sexual contact with an infected person, it can also be transmitted from a mother to her fetus resulting in congenital syphilis.

What is syphilis?

Syphilis is a chronic, systemic, sexually transmitted infection (STI) caused by the bacterium Treponema pallidum subsp. pallidum. It has been recognized for centuries and remains a major public health concern because, if untreated, it can progress through multiple stages and cause severe complications affecting multiple organs (heart, brain, eyes, nerves, bones, and skin).

Stages of syphilis

Untreated syphilis is chronic disease with sub-acute symptomatic periods separated by a symptomatic intervals, during which the diagnosis can be made serologically.  The progression of untreated syphilis is generally divided in to stages. Initially, T. pallidum penetrates intact mucous membranes or enters the body through tiny defects In the epithelium.

1.     Primary syphilis:

At the end of the incubation period, a patient develops a characteristics primary inflammatory lesion called a chancre at the point of initial inoculation and multiplication of the spirochetes. Generally it is relatively painless and commonly located around the genitalia, but in about 10% of cases lesions may appear almost anywhere else on the body e.g. throat, lip and hands.

2.     Secondary syphilis:

Within 2 to 8 weeks after the appearance of the primary chancre, a patient may develop the sign and symptoms of secondary syphilis when organisms gain access to the circulation from the infected site. The secondary stage is characterized by a generalized illness that usually begins with symptoms suggesting a viral infection headache, sore throat, low-grade fever and occasionally nasal discharges.

3.   Latent syphilis

After resolution of untreated secondary syphilis, the patient enters a latent non-infectious stages in which diagnosis can be made only by serologic method. During the first 2-4 years of infection, one fourth of patients will show relapses of manifestation of secondary syphilis. During these relapses, patients are infectious, and underlying spirochetemia may be passed translucently to the fetus. 

4.  Tertiary syphilis

The first manifestations of late syphilis are usually seen from 3-10 years after primary infection. About 15% of untreated syphilitic individuals eventually develop late begins syphilis characterized by the presence of destructive granulomas. Untreated patients 10% develop cardiovascular manifestations. Degenerative changes in CNS (paresis (muscle weakness - partial inability to move), tabes (progressive wasting of the body), and cardiovascular lesion (aortitis, aortic aneurism, and aortic valve insufficiency). In all tertiary lesions, treponemes are very rare, They are cause by the body’s hyper immune reaction to remaining spirochetes.  Few organisms are present.

5.  Congenital syphilis

Congenital syphilis is caused by maternal spirochetemia and transplacental transmission of the microorganism usually after 18 weeks of gestation. Congenital syphilis is diagnoses in three fourths of the cases in patients over 10 years of age. Early congenital syphilis appears either at birth or up to two years of age. T.pallidium can cross placental barrier, the fetus will die in utero or may die shortly after birth if delivered babies will have severe congenital and developmental anomalies.  A pregnant syphilitic women can transmit T.pallidium to the fetus through placenta beginning in the 10th to 15 weeks of gestation.

How to transmission syphilis

Syphilis is transmitted when Treponema pallidum (the bacteria that causes syphilis) passes from one person to another. The main routes of transmission are:

1. Sexual contact:

Through vaginal, anal, or oral sex with an infected person. Bacteria enter the body through small cuts or mucous membranes in the genital area, rectum, lips, or mouth.

2. Mother-to-child transmission (congenital syphilis):

An infected pregnant woman can pass syphilis to her baby during pregnancy or childbirth. This can cause stillbirth, premature birth, or severe illness in the newborn.

3. Blood-related transmission:

Through transfusion of unscreened blood (now rare due to testing). Sharing contaminated needles or equipment.

Epidemiology

•  Syphilis is exclusive to humans.

•  Commonly transmit direct sexual contact.

•  Transplacentally, through blood transfusion is also possible.

•  Very delicate it cannot survive on dry skin surfaces.

Tests for syphilis

Serologic procedures for syphilis include the flowing. Nontreponemal method e.g. Venereal disease research laboratory (VDRL) and the rapid plasma regain (RPR) procedures.Treponemal methods e.g. fluorescent treponema pallidum antibody absorption and microhemagglutination treponema pallidum.

1. Nontreponemal methods

Nontreponemal methods are screening tests for syphilis that detect regain antibodies. They are inexpensive and useful for diagnosis and monitoring treatment response, but they are not specific and may give false positive results. Common examples are VDRL, RPR, and TRUST. Venereal diseases research laboratories (VDRL) test  It is flocculation test in which particles of cardiolipin form visible clumps when combined with reagin antibodies in serum or CSF. The suspension is shaken and the reaction occurs in few minutes, It is read by the microscope. RPR- It is another flocculation test performed on plasma and is read by the naked eye. Non treponemal tests show negative results in many patients with initial chancre.

Advantages of Non-treponemal test

• More rapid

• Simple & cheap

• Mainly used for screening & epidemiologic purpose

• Used to evaluate the effect of treatment since they revert to negative in 6 -18 month after effective treatment

2. Treponemal methods

• Specific antibody tests

• Used to confirm positive reactions with VDRL or RPR tests

• Use T.pallidum as the antigen

•  More complex and expensive

•  They are used primarily as a confirmatory test

• They remain positive for life even after effective treatment

• Positive in late syphilis

• Tests uses T. pallidum as antigen

• Treponemal tests detect specific treponemal antibodies

•  FTA-Abs (Fluorescent treponemal antibody absorption test)

• TPI (Treponema pallidum immobilization) test

• TPHA (Treponema pallidum hemagglutination) test

Haw to treatment syphilis

• Penicillin is still effective in treating syphilis.

•  Syphilis of < one year → single intramuscular injection

•  Older or latency syphilis → given 3 times at weekly interval.

• Neurosyphilis → the same therapy.

•  Reinfection in treated persons is common

Haw to prevention syphilis

 Safe sex and treatment of patient and partners are best prevention.

Conclusion

Syphilis is a serious sexually transmitted disease that can cause severe health problems if left untreated, but it can be easily cured with early detection and proper treatment.