Syphilis derives its name from a poem by a physician, Girolamo Fracastoro (1478—1553), published in Venice in 1530. The poem tells of the shepherd, Syphilus, who was struck down by the disease as a punishment for insulting Apollo.
On his return from Haiti in 1493, Christopher Columbus (1451—1506) brought back syphilis, parrots and rare plants. The King and Queen of Spain received him with highest honours.
For a detailed description of venereal syphilis, reference should be made to a textbook on sexually transmitted disease
Acquired syphilis is an STD infection caused by Treponema pallidum, a delicate spiral organism (spirochaete), 6—15 m in length. A dramatic decline in incidence after the introduction of penicillin has been followed by a gradual but significant increase throughout the world.
Transmission is by direct contact with a surface lesion containing treponemes, which penetrate the skin or mucosa at the point of contact. Since treponemes are present only in the surface lesions of early syphilis, i.e. primary, secondary and the first 2 years of latency, syphilis is only infective during that period. After 2 years, acquired syphilis is rarely communicable and the ulcerative cutaneous lesions of tertiary syphilis are not infective as they contain few, if any, treponemes. The organism dies rapidly on drying, hence infective early lesions are predominantly sited on moist areas, e.g. genitals, mouth and anus, so that infection almost always occurs during intercourse including orogenital contact and —of great importance now — homosexual practices involving the anus and rectum.
The disease is divided into four stages: primary, secondary, latent and late.
Primary syphilis. A primary sore or chancre develops at the site of entry of the treponemes in about
3—4 weeks. It may resolve at any stage of its development and thus be quite atypical. It may simulate other penile or vulval lesions, traumatic lesions such as splits or tears chancroid, herpes genitalis, burns, furuncles and carcinoma, as well as balanoposthitis and lymphogranuloma venereum .
Starting as an indurated papule, it becomes eroded and when fully developed will present the following signs of a classic Hunterian chancre: a shallow, indurated, painless, nonbleeding ulcer, usually single, oval or round, with a raised hyperaemic margin, often extending into a dusky red oedema. A painless, discrete and ‘shorty’ enlargement of the associated lymph nodes occurs which has a rubbery consistency. The prepuce of the penis must always be fully retracted as otherwise tiny sores in the coronal sulcus may be missed. As there are no constitutional symptoms, a female patient will be unaware of the presence of a cervical chancre, a lesion which accounts for about 45 per cent of all sores in that sex. Extragenital chancres of the lip1, tongue, nipple, etc., are now rare, but rectal and perianal primaries are common in homosexuals and are usually atypical, frequently resembling painful anal fissures which occasionally get excised in error. Spasm of the anal sphincter is usually less with true sores and a typical (lateral) inguinal lymphadenitis may be present.
Diagnosis is by finding T pallidum in the clear exudate from the lesion by dark-field microscopy. The serum tests do not become positive for 10—90 days (usually 3—5 weeks) after the appearance of the chancre, hence initial negative results must never be interpreted as excluding primary syphilis. This is because the tests identify a gradually developing antibody response. The tests should be repeated for up to 3 months where doubt persists.
Secondary syphilis. Signs usually appear in 6—12 weeks, extremes being 3 weeks to 6 months. The commonest sign is a dull red or coppery rash, which is generalised, symmetrical, indolent and nonirritant. Often inconspicuous, sometimes absent (in 25 per cent of cases), the rash is characteristically pleomorphic, being roseolar or macular at first, with papular, papulosquamous or other elements appearing later. Papules on contiguous moist sites, e.g. vulva and perineum, may enlarge to form condylomata lata, fleshy, wart-like growths teeming with treponemes. Small, round, superficial erosions may occur in the mouth where they may coalesce to form the so-called snail-track ulcers. The rash can resemble that of any known rash-producing condition in the whole of medicine. A generalised, painless lymphadenopathy often occurs, and less common symptoms include sore throat, hoarseness, ‘moth-eaten’ alopecia, hepatitis, inns, and bone and joint pains. Bone pains may be severe and prolonged for several weeks without any other supporting signs, and the diagnosis is often missed. Acute meningitis or cranial nerve or spinal root palsies due to an irregular pachymeningitis occur. Constitutional effects, malaise, headache, backache and pyrexia, normally mild, are occasionally of prostrating severity. Secondary syphilis is also a cause of pyrexia of unascertained origin (PUO).
Full spontaneous recovery always occurs.
Latent syphilis. This follows the untreated secondary stage and lasts from 2 years to a lifetime. There are no signs, but the serum tests are positive.
Late syphilis (syn. tertiary syphilis). Syphilis in all its stages is essentially a vascular disease. In each stage, treponemes cause inflammatory reactions in the perivascular lymphatics with plasma cell cuffing of terminal vessels. In the tertiary stage only there is subsequent obliterative endarteritis, tissue necrosis and fibrosis. Since almost any structure may be involved, the signs can be extraordinarily variable, and will be referable to the site or system involved. Only about 35 per cent of untreated syphilitics will develop tertiary syphilis. About 5—15 years after infection, 10 per cent will develop neurosyphilis, 10—12 per cent cardiovascular syphilis and after 6 months up to many years later, 10—15 per cent will develop late benign syphilis involving less vital structures. The three types are not mutually exclusive. The typical lesion of late benign syphilis is the localised gumma or diffuse gummatous infiltration. The gumma is a syphilitic hypersensitivity reaction consisting of granulation tissue with central necrosis. Sloughing of a subcutaneous gumma may produce the typical, painless, punched-out gummatous ulcer with a ‘wash-leather’ base . On healing, it leaves a silvery ‘tissue-paper’ scar. Alternatively, the gummatous process may be nodular or infiltrative without ulceration, and slow peripheral spread occurs with central healing. The individual lesions are round and indurated, and grouped lesions are circinate in outline with sharply defined, hyperpigmented margins.
Diagnosis. Dark-field microscopy. This is performed on aspirates from skin or mucous membrane lesions and is the quickest method of diagnosis in early acquired syphilis.
Serological tests for treponemal diseases are of two types.
1. Nonspecific (syn. reagin, nontreponemal, lipoidal antigen tests). Examples are the cardiolipin Wasserman (WR), Kahn, Meinicke, and Venereal Disease Research Laboratory (VDRL) slide test. The last is the best. These test the presence of any antibody reagin in the serum of patients with treponemal infections, but biological false positives (BFP) arise from reagin present in nontreponemal conditions, e.g. malaria, vaccinia, glandular fever, and also after any kind of vaccination. Stronger and persistent reactions may occur in leprosy, sarcoidosis, collagen diseases and chronic liver disorders. A diagnosis of syphilis requires confirmation from one or more of the specific tests.
2. Group-specific tests (treponemal antigen tests). Examples are: Reiter’s protein complement fixation test (RPCF), Treponema pallidum haemagglutination assay (TPHA), absorbed fluorescent antibody test (FTA Abs) and Treponema pallidum immobilisation test (TPI).
The first is obsolescent (in the UK) and the last rarely required. The routine practice is to perform the VDRL and TPHA adding the FTA if either is positive or the clinical findings justify it. In primary syphilis, the usual order of conversion is ETA, VDRL with rising titre and TPHA, although this sequence is not invariable. After treatment, the VDRL usually reverts to negative in up to 6 months, the FTA in 70 per cent, but the TPHA hardly ever, of which facts the patients must be told — ‘a little scar in the blood’ is usually adequate. Persistence of treponemal antibodies, if it is known that adequate treatment has been given, is not a cause for concern but if there is any doubt, confirmed reactions on repetition should be treated as for latent infection.
No local treatment except isotonic saline should be applied to a suspected chancre until dark-field examinations have proved negative on 3 successive days. No treponemicidal antibiotics should be prescribed until syphilis is confirmed or excluded, but if there is secondary infection a course of sulphonamides may help. Penicillin has supplanted all other forms of treatment. A high cure rate is achieved in early syphilis with intramuscular procaine penicillin G 1.2 g daily for 15 days. This dosage is prolonged to 21—30 days for late syphilis. Clinical and serological observation should be continued for 2 years after treatment. In penicillin-allergic patients, tetracycline and erythromycin are alternatives. The best treatment is doxycycline 100 mg twice daily for the equivalent period.
Janisch—Herxheimer reaction. About 6 hours after the first injection, 60 per cent of early syphilitics will develop pyrexia, malaise and possible rigors lasting for a few hours only. Patients must be warned about this. The reaction is infrequent in late syphilis, but may be more serious. In late cases only, prednisone 10 mg four times daily for 3 days before the main treatment should prevent it.
Prognosis is excellent after standard treatment for early syphilis. In late syphilis, particularly of the cardiovascular system, cure of the underlying disease may not significantly improve the condition of the patient.
Transmission. Infection occurs when treponemes from an infected expectant mother cross the placental barrier to the foetal circulation. The more recent the mother’s infection, the more likely is this to occur and the more serious the effects on the child. The results of foetal infection vary from death in late foetal life or early infancy, or the birth and normal development of an apparently healthy child who, nevertheless, has latent congenital syphilis.
Early congenital syphilis. Signs in the newborn, which may be delayed for a few weeks, include a generalised rash, mucous erosions as in secondary syphilis and the ‘souffles’, a syphilitic rhinitis with nasal discharge which interferes with suckling causing loss of weight, epiphysitis, periostitis, osteochondritis, hepatosplenomegaly and basal meningitis. Signs may be so slight as to escape notice or so severe as to cause death in early infancy, usually due to syphilitic ‘pneumonia alba’.
Late congenital syphilis. The extraordinary variety of clinical manifestations which can occur in acquired tertiary syphilis can also occur in childhood or puberty in late congenital syphilis, e.g. congenital neurosyphilis, cutaneous, visceral or skeletal gummata, but congenital cardiovascular syphilis is practically unknown. In addition, some manifestations, the stigmata, occur in congenital, but never in acquired, syphilis.
The stigmata of late congenital syphilis (Hutchinson’s classic triad) consist of the following:
1. interstitial keratitis: the most frequent of the stigmata is a syphilitic hypersensitivity reaction with onset between 5 and 15 years. The cornea becomes inflamed causing pain, lacrimation and photophobia. It tends to be bilateral and recurrent. Prolonged severe recurrent attacks result in a hazy ‘ground glass’ appearance of the cornea, with yellowish-red corneal patches in severe cases (salmon patches, not to be confused with the salmon-patch birthmark). It is uninfluenced by antisyphilitic treatment but can be controlled by local cortisone treatment;
2. eighth nerve deafness: a progressive, bilateral, perceptive deafness, onset about puberty, but occasionally delayed until later and uninfluenced by treatment;
3. Hutchinson’s teeth: a peg or band-shaped deformity of the upper central incisors, second dentition. Moon’s molars (mulberry molars):
the 6-year molars erupt with dwarfed cusps. Other classic signs include nasal deformities, e.g. saddle nose , collapsed nasal septum , perforation of the palate , sabre tibia, Glutton’s joints (painless effusions, commonly in the knee joint) and parietal bossing
prevention and treatment. A dosage of 1.2 million units of procaine penicillin G given to the mother for 15 days as early as possible in pregnancy not only will protect her from the ravages of late syphilis, but will prevent infection of the foetus, or may even cure it in utero, if already infected. An infected neonate, whose mother received no treatment during pregnancy, should be treated as for late acquired syphilis with the dosage adjusted to weight.
Neonatal serology. An expectant mother who has received no treatment during pregnancy, or who is an untreated latent syphilitic, may produce a child free from syphilis but seropositive owing to passive transfer of maternal antibodies. This serological problem can be solved by performing tests on the immunoglobulin G (IgG) and 1gM fractions of the infant’s serum but not on the cord blood. In the case of passive transfer, the IgG tests will be positive and the 1gM tests negative. Positive 1gM tests indicate active disease in the child since the 1gM fraction of the maternal serum proteins does not cross the barrier of the normal placenta. Exceptions occur if the placenta has been damaged from other causes. In all cases, careful clinical and serological follow-up of mother and child is essential. The virtual disappearance of congenital syphilis from the UK and similar countries is one of the great triumphs of modern medicine.
Syphilis contacts. At all stages of the disease, the known contacts must be followed up. This applies to late and congenital cases when other members of the patient’s family are often found to have untreated latent syphilis.
Yaws is an endemic disease of rural areas in tropical countries of high humidity. The causative organism, Treponema pertenue, appears indistinguishable from T pallidum and produces identical serological reactions. Direct contact with an early lesion is the usual mode of transmission. It is not sexually transmitted. The primary lesion is most frequently seen on the legs of children. About a month after infection, a papule appears at the site of entry of the treponeme; this ulcerates giving the lesion a pink, raised, raspberry-like (framboesia2) appearance. Secondary lesions, usually papillomatous, appear some weeks later. After 5 or more years of latency, a minority of patients develops late gummatous-like lesions of soft tissue or bone similar to those of tertiary syphilis. The cardiovascular and nervous systems are not involved and congenital yaws does not occur. Treat as for syphilis.
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