Treponema

CASE 1

• A 32 year old man has an ulcer on the shaft of his penis. The ulcer developed from a small papule at the site; it eroded and became indurated ("swollen"). The base of the ulcer is pink, smooth, and non-necrotic. The edges of the ulcers are slightly raised. The ulcer is not painful but is somewhat tender if squeezed.

• The patient has no fever, and his vital signs are normal. The ulcer is as shown below. There is no inguinal lymphadenopathy. There are no rashes.

• The physician orders a VDRL test. In addition, he has access to a darkfield microscopy. So, he scrapes the base of the ulcer and suspends the scrapings onto a slide with a drop of normal saline. Viewing the unstained material under a coverslip, the physician sees the following organisms. As he views them, the viable bacteria are moving with a bending or folding motion.

• The patient is treated with a single injection of long-acting (benzathine) penicillin, and the ulcer resolves. The VDRL test returns positive the following day.

Questions:

1. The female sexual partner from whom this patient acquired infection has no ulcer or other symptoms. She denied that she was the source; however, her VDRL is also positive. How can you explain this?
2. What would have been the course of the ulcer had the patient not been treated with penicillin?
3. Why are these organisms shaped like coiled springs?
4. What is a VDRL (or RPR) test? What does the test assay in the patient sample?
5. Does having a positive VDRL always confirm that a patient has syphilis?
6. Should the patient also be tested for HIV?

CASE 2

• A 35 year old man has fever and malaise for one week, not responsive to antimalarial medication. His appetite is poor and his joints ache. Four weeks earlier, he had a small ulcer on his penis, but this resolved without any medical attention or medications.

• On physical examination, he is febrile to 38.8 degrees. Examination of the mouth reveals moist white patches on the patients tongue. There is diffuse lymph node enlargement in the neck, the axillae and the inguinal regions. He also has an enlarged epitrochlear node on the left. The patient has a non-itchy rash all over his skin, including the palms of his hands and the soles of his feet (see below). Under his chin, there are numerous pustules (below).

• A darkfield microscopic examination of material scaped from the tongue shows numerous treponemes as pictured in Case #1. A VDRL test is sent, and the patient is treated with benzathine penicillin.

• Two hours after the injection of penicillin, the patient develops a shaking chill with a rise of his temperature to 40 degrees. His pulse is rapid and weak (rate=135/min). His blood pressure drops to 90/50 mm Hg and he feels dizzy and weak. The patient is treated with paracetamol and one liter of intravenous saline. This episode resolves after 12 hours and does no recur. The fever and the rash are gone after three days.

• The following day, the patient's VDRL test returns negative. However, the laboratory dilutes his serum one-hundred-fold and repeats the test. After dilution, the serum tests strongly positive.

Questions:

1. Does this patient have syphilis? If so, what stage of the disease does this patient have?
2. He has fever, adenopathy, rash, and white patches on the mucous membranes. Do these manifestations always occur with this disease? What other clinical features may be present in other patients?
3. Why did the patient have an apparent "septic episode" with high fever and hypotension after receiving penicillin? Is this an allergic response to pencillin? If not, what caused it, and why were additional antibiotics not given?
4. Why was the VDRL done on undiluted serum negative (hint: the VDRL and RPR are agglutination tests)?
5. Should this patient expect to have later complications of syphilis?
6. A medical student examined this patient without wearing gloves. She had a recent knife cut on her right index finger. Should she be concerned?

CASE 3

• A 72 year old woman has increasing shortness of breath with exertion. At present, she is unable to climb even one flight of stairs without stopping to rest and catch her breath. This symptom started over a year ago and has gradually worsened.

• The patient is afebrile with a heart rate of 110/min and a blood pressure of 180/70 mmHg. Cardiac examination reveals a loud diastolic murmur heard along the left sternal border consistent with aortic valve regurgitation. The patient is also noted to have a firm, non-inflammed enlargement of the left knee (below). A neurological examination revealed decreased vibratory and light touch sensation in the feet, and the patient was noted to slap her feet on the ground when she walks.

• A chest xray reveals a large ascending aortic aneurysm (arrows).

Questions:

1. Does this patient have syphilis? If so, what stage of the disease?
2. What has happened to the heart to cause the aortic valve to become incompetent? Will penicillin correct this problem?
3. Why is the patient's knee enlarged? Will penicillin therapy resolve this problem?
4. What other manifestations of disease may occur in this setting?

CASE 4

• A 14 year old girl has a series of ulcerated lesions on her leg and thigh. The first of these lesions began on right anterior leg from a papule that enlarged and erupted into and ulcer. The lesion was itchy, and the girl scratched it frequently. This lesion healed after a few weeks, but several new lesions developed on posterior leg and thigh (see below). She had no fever or lymphadenopathy.

•A VDRL assay was requested, and the result was postive. the patient was then treated with a single dose of long-acting (benzathine) penicillin, and all of the lesions resolved.

• To identify a source of the patient's skin lesions, her brothers, sisters, and cousins from the village were examined. One brother was found to have an irregular skin ulcer on his anterior lower leg (below). His VDRL test was also positive, and he was treated with penicillin as well.

Questions:

1. Do these children have syphilis? If not, what do they have?
2. Why is the VDRL positive in these children? Is this infection caused by Treponema pallidum?
3. How were these infection acquired?
4. What may be the consequences of not recognizing and treating these infections?
5. If you wished to attempt to eradicate this infection, how would you go about it?