bubble_chart Overview

Granuloma inguinale is a chronic, grade I pestilence sexually transmitted disease caused by the bacterium Klebsiella granulomatis. This bacterium appears as oval-shaped bodies within mononuclear cells of infected tissues, known as Donovan bodies, hence the disease is also called donovanosis. It is a chronic pestilence characterized by granulomatous patches, primarily affecting the anus and external genitalia, forming painless ulcers that can spread through autoinoculation.

bubble_chart Epidemiology

In addition to sexual transmission, it can also spread through pubic lice, making it a chronic pestilence. Apart from the genital and groin areas, it can also affect the face, back, and other regions, warranting vigilance.

bubble_chart Pathogen

The causative agent of this disease is the granulomatous capsule bacillus, an intracellular microorganism, a Gram-negative short rod-shaped bacterium. In recent years, some have considered this bacterium to be a schizomycete, existing both inside and outside mononuclear cells in granulomatous tissue, forming macrophages within vacuoles, measuring 0.6μm × 1.5μm. The histiocytes of this bacterium sometimes aggregate 20–30 in the vacuoles of cells due to the proliferation of polymorphonuclear leukocytes and macrophages, and are released from the cells, hence also called Donovan bodies.

The granulomatous capsule bacillus is difficult to culture successfully in artificial media, and its biological characteristics remain largely unknown. However, some have succeeded in culturing the bacterium in egg yolk-containing media, but re-inoculating the cultured pathogen into humans did not produce lesions resembling granuloma inguinale. Due to the inability to culture it successfully in artificial media, bacteriological examination is extremely challenging. Serological tests also find it difficult to confirm.

Microscopic examination: A small piece of diseased tissue is taken from the lesion site, made into a smear, dried, and prepared as a specimen. Staining with Giemsa or Wright's stain is performed. Observation under an oil immersion lens at 10×100 magnification reveals the granulomatous capsule bacillus as large histiocytes aggregating within the protoplasm to form Donovan bodies, appearing blue-black. Although successful inoculation within egg yolk sacs has been achieved, proving its non-motility and Gram-negative nature, this has little practical value clinically. Pathological tissue biopsy: Samples are taken from the deep edges of the granulomatous tissue. The biopsy procedure involves Giemsa staining, revealing blue-black Donovan bodies, which are also visible under electron microscopy.

bubble_chart Clinical Manifestations

1. Incubation period: Ranges from 8 to 84 days, but most cases occur around 30 days after sexual contact.
2. Affected areas: Primarily occurs in the genital regions, such as the male foreskin, coronal sulcus, glans penis, penile shaft, and frenulum, as well as the female labia majora, labia minora, and labial frenulum. In women, sexually transmitted disease lesions often start at the labial frenulum and spread forward along the vulva in a "V" shape. About 10–15% of patients may involve the perianal area (especially in homosexual individuals) and the groin. Approximately 6% of patients may experience hematogenous or lymphatic dissemination to non-genital areas and internal organs, such as the neck, nose, oral cavity, limbs, chest, abdomen, buttocks, intestines, liver, kidneys, bone marrow, and joints. Pregnant women are more prone to hematogenous spread, and childbirth can cause cervical lesions to spread upward into the uterus.
3. Lesion morphology: Begins with papules, vesicles, or pustules, accompanied by intense itching. These may rupture due to scratching or spontaneously, forming ulcers. The ulcer surface is soft, with yellowish exudate, slightly reddened edges, and a superficial grayish-white or yellowish coating with a foul odor. Multiple ulcers may merge and gradually expand in size, generally showing no tendency for spontaneous healing. Fixed ulcers may form masses, with proliferative granulation tissue at the base. The exudate is highly infectious and destructive. Due to autoinoculation, the ulcers may spread along skin folds or extend outward in a serpentine pattern. In severe cases, the penis, labia, or other tissues may be destroyed, even reaching deep tissues, often due to mixed infections. In women, swollen labia may resemble elephant hide disease.

Skin lesions develop, but lymph nodes are rarely involved, and visceral metastasis is uncommon. The subcutaneous nodule test for bacterial reaction is negative.

The disease progresses very slowly, sometimes lasting years. Some cases may resolve spontaneously without treatment, but recurrence is possible.

Complications: Lymphatic obstruction may lead to pseudoelephantiasis of the external genitalia, such as the labia, clitoris, penis, or scrotum. Scarring and adhesions may cause strictures in the urethra, vagina, or anus. Malignant transformation and severe genital mutilation may also occur.

bubble_chart Diagnosis

The diagnosis is confirmed based on sexual contact history, clinical manifestations (such as initial genital nodules, characteristic raised edges, and painless beefy red granulomatous ulcers), and laboratory tests. Silver staining can identify Donovan bodies in pathological tissue sections. However, the preferred method is to locate Donovan bodies using tissue smears. This involves performing a punch biopsy at the lesion's edge or making a deep incision to obtain a small tissue sample. The specimen is then crushed between two glass slides, air-dried, fixed with formaldehyde, and stained with Wright or Giemsa for microscopic examination. Donovan bodies appear as round or oval structures, 1–2 μm in size, within the cystic spaces of large mononuclear cell cytoplasm. Their capsules are stained as an eosinophilic dense band surrounding the bacteria, with chromatin concentrated at both poles, giving them a safety pin-like appearance. Characteristic mononuclear cells measure 25–90 μm in diameter and contain numerous cystic spaces filled with Donovan bodies.

bubble_chart Treatment Measures

This disease can be effectively treated with antibiotics, particularly oxytetracycline, tetracycline, and streptomycin. The recommended course of treatment is generally no less than 10 to 15 days, with a dosage of 500mg each time, four times a day. Penicillin is ineffective. Previously, the prognosis was poor, but with the development and application of modern antibiotics, the prognosis has significantly improved.

bubble_chart Differentiation

Early genital ulcers and anal lesions should be differentiated from soft chancre and the hard chancre and condyloma latum of syphilis; chronic ulcers or scars of sexually transmitted diseases should be differentiated from sexually transmitted lymphogranuloma.

Differential diagnosis of granuloma inguinale