Free Microbial Infection: Syphilis Essay Sample
Syphilis is a sexually transmitted disease (STD) caused by Treponema pallidum, a gram-negative bacterium of the phylum spirochetes. Human beings are the only known reservoirs. It is primarily spread from one person to another through sexual contact with syphilitic sores and infected mucus membranes. The sores occur mainly on the external genitalia, vagina, anus and rectum. They can also occur on the mouth and lips. As a result, syphilis can be spread through kissing, oral, vaginal or anal sex. Syphilis can also be transmitted from an infected pregnant mother to her unborn child, a case referred to as congenital syphilis. The longer the mother has been infected, the higher the chances of a stillbirth. The disease is prevalent in the sexually-active age group and the incidences are higher in men as compared to women.
In congenital syphilis, more than two-thirds of the children are born without symptoms. Over the next two years they start showing symptoms like fever, rashes, pneumonitis, abnormal enlargement of the liver and spleen, and neurosyphilis. If untreated, the disease proceeds to late congenital syphilis in 40% of the cases, leading to complications like symmetrical swelling of the joints (mainly the knees) known as Clutton's joints, anterior deformation of the tibia known as saber shin, collapse of the nose bridge leading to saddle nose deformation, and higoumenakis sign- a unilateral enlargement of the clavicle where it joins the sternum. In adults, the disease can remain asymptomatic for years, or present as the more common skin diseases. Symptomatic progression of syphilis is divided into four stages namely primary, secondary, latent and secondary. After initial exposure, the incubation period takes an average of 21 days, though it varies between 3-90 days, before initial signs appear.
The initial sign is usually the appearance of a skin lesion known as a chancre at the point of contact. The chancre is usually a small, round, firm, painless open sore or ulceration. A few cases have multiple lesions, and lesions outside the genitals can sometimes be painful. There is usually swelling of lymph nodes in the area near the chancre. The lesion heals by itself within 3-6 weeks after initial appearance. Without proper treatment the disease progresses to the secondary stage.
Signs of the secondary stage begin to appear 4 to 10 weeks after the primary stage, and are characterized by skin rash and lesions on mucous membranes. The rash is the most common type of symptom at this stage and is very characteristic. It attacks the palms of the hands and the soles of the feet and presents as rough, reddish-brown spots. The rash may become macular, papular or pustular. The appearance of the rash may be different in other parts of the body like the trunk and extremities, sometimes mimicking the rashes of other diseases. In a few cases, the rash may be so faint that it goes unnoticed, after all the rashes are non-itchy. Sores known as mucous patches may also develop around the mouth, penis and vagina. On the mucus membranes, genitals and skin folds; moist, wart-like lesions called condyloma lata are seen. These appear as broad, flat and whitish lesions. All these lesions fester with bacteria that can cause infection when they come in contact with a healthy person. The secondary stage also presents with other non-specific symptoms like fever, headache, malaise, patchy hair loss, lymphadenopathy, weight loss, myalgia, sore throat, fatigue and visual disturbances due to optic neuritis and uveitis. In rare cases, additional manifestations are seen in the form of hepatitis, interstitial keratitis, periostitis, arthritis and kidney disease. Proper treatment leads to resolution of all these symptoms. Without treatment, the lesions heal on their own after 3-6 weeks, but the disease progresses to the latent and later stages.
At this stage, the signs and symptoms of syphilis disappear but the patient is still infected and this can be proven by a blood test. If the latent stage comes less than one year after secondary stage, it is called early latent stage. This is dangerous as symptoms of secondary stage can relapse, and the patient is highly contagious. If the latent stage occurs more than one year after the secondary stage, it is called late latent stage. There are no relapses, and the patient is asymptomatic and less contagious.
This stage occurs about 3-15 years after initial infection and can last for several years. The signs and symptoms vary widely and are difficult to diagnose. They include gradual blindness, numbness, poor coordination of muscle movements, paralysis and dementia. These symptoms can be severe enough to cause death. The disease attacks internal organs, and the stage can further be subdivided into three groups according to the organ(s) attacked. These are:
Cardiovascular syphilis. This occurs about 10-30 years after initial infection and attacks the aorta of the heart, leading to the most complication called syphilitic aortitis. Weakening of the aortic walls also leads to development of aneurysms.
Gummatous syphilis. Occurs averagely 15 years after infection and attacks the skin, bones and liver leading to formation of tumor-like swellings called gummas. These are soft, round balls of inflammation of various sizes.
Late neurosyphilis.Syphilis can also affect the central nervous system in the late stages of the disease, about 4-25 years after initial infection. It may be asymptomatic in the early stages, or present as syphilitic meningitis that later develops meningovascular syphilis.
There are several ways of diagnosing syphilis. These include:
Dark-field microscopy- This involves drawing fluid from the syphilitic chancre and observing it under a specialized dark-field microscope. Syphilis bacteria can be seen under the microscope.
Serology- Blood is drawn that can be used for treponemal and nontreponemal tests. Treponemal tests include Treponemal Pallidum Particle Agglutination Test (TPHA) and Fluorescent Treponemal Antibodies Absorption Test (FTA-Abs). Non-treponemal tests include Rapid Plasma Reagin (RPR) and Venereal Disease Research Laboratory (VDRL).
Cerebrospinal fluid examination- An observation is made of elevated levels of protein and high numbers of leucocytes especially lymphocytes.
For the early stages of infection, the drug of choice for uncomplicated syphilis is intramuscular injection of penicillin G. Cephtriaxone has been shown to be as effective as penicillin. Alternative drug choices include doxycline and tetracycline, but these are contraindicated pregnant mothers. For the later stages of the disease, intravenous penicillin is given. Once treatment is commenced, the rupturing syphilis bacteria release endotoxins that trigger the body's immune system to release cytokines. This reaction can lead to a serious side effect known as Jarisch-Herxheimer reaction which presents with headache, fever, pain in the muscles and slow heart rate.
Syphilis is best prevented by practicing safe sex and avoiding risky sexual behavior. Using condoms does not fully eliminate the risk. Pregnant women should all be screened for syphilis during antenatal clinic.
Proper treatment regimen in the primary and secondary stages can fully cure syphilis and prevent the complications seen in the late stages. The syphilitic sores make it easier for one to transmit or get infected by HIV. The risk of HIV infection after exposure is 2 to 5 times greater in syphilis patients. Untreated syphilis has a mortality rate of about 8 to 58 % and kills more males than females.