AIDS is the abbreviation of acquired immunodeficiency syndrome (AIDS), which is a chronic infectious disease caused by human immunodeficiency virus (HIV). This disease is mainly transmitted through sexual contact, blood, and mother to child transmission. HIV mainly invades and destroys CD4+T lymphocytes, causing damage and even defects to the body’s immune cells and/or functions, ultimately leading to various serious opportunistic infections and tumors. It has the characteristics of rapid transmission, slow onset, and high mortality rate.
epidemiology
contagious
It is contagious and belongs to Class B infectious diseases.
source of infection
People infected with HIV are the source of infection of the disease, including HIV infected people and AIDS patients. HIV mainly exists in bodily fluids such as blood, semen, vaginal secretions, cerebrospinal fluid, pleural and peritoneal fluids, amniotic fluid, and breast milk from the source of infection.
route of transmission
The transmission of HIV requires damaged mucous membranes or skin to come into contact with infected individuals’ bodily fluids containing the virus, so shaking hands, hugging, and other forms of contact with infected individuals generally do not transmit the virus. The HIV virus is mainly transmitted through the following pathways:
- Sexual contact transmission
Sexual transmission is mostly caused by unprotected sexual activity with HIV infected individuals. There is a large amount of virus in the semen or vaginal secretions of HIV infected individuals. During sexual activity (including vaginal intercourse, anal intercourse, oral sex, etc.) between both partners (of the same sex and opposite sex), friction between sexual organs can easily cause damage to the genital mucosa. The virus enters the bloodstream of uninfected individuals through skin and mucosal breaks, causing transmission.
- Blood and blood products
(1) Sharing needles, syringes, cotton swabs, etc. for injection (drugs).
(2) Accidentally puncturing the skin with a needle or other sharp object infected with HIV virus.
(3) Irregular medical procedures, such as dental procedures, tattoos, etc.
(4) Use contaminated blood products.
- Mother to child transmission
Including intrauterine infections, transmission during childbirth, and breastfeeding.
- Other less common situations
(1) Using organs contaminated with HIV for transplantation surgery.
(2) During the process of artificial insemination, HIV carrying semen was received.
(3) Some professionals who have contact with AIDS patients, such as medical staff, barbers, etc., may also be infected by accidental exposure (such as puncturing the skin).
incidence rate
- The United Nations AIDS Programme estimates that by the end of 2017, there were 36.9 million living HIV/AIDS patients worldwide, 1.8 million new HIV infected people that year, and 21.7 million people were receiving highly effective combined antiretroviral treatment.
- As of the end of 2017, there were 758610 reported active HIV/AIDS patients in China, 134512 new HIV/AIDS patients were discovered that year (over 95% of whom were infected through sexual means), and 30718 deaths were reported that year.
incidence trend
In recent years, the incidence rate of AIDS has increased year by year.
Easy to reach people
The general population is susceptible, and high-risk groups include:
- Men who have sex with men of the same sex;
- Intravenous drug users;
- Sexual contact with HIV/AIDS patients;
- Multiple sexual partners population;
- Sexually transmitted infection population.
cause of disease
executive summary
The main cause of AIDS is the infection of HIV virus through various ways. HIV virus invades the human immune system, including CD4+T lymphocytes, monocyte macrophages and dendritic cells. The main manifestation is that the number of CD4+T lymphocytes is constantly decreasing, which eventually leads to the deficiency of immune function of human cells, causing various opportunistic infections and tumors.
Risk factors
- High risk sexual behavior
It mainly refers to the increased risk of contracting the virus when not using condoms correctly throughout the entire process, especially when having sexual relations with high-risk partners. Sexual transmission is mostly caused by unprotected sexual activity with HIV infected individuals.
- Male Male Behavior
Many gay men engage in anal sex. The anatomical structure of the anus and rectum is different from that of the female vagina. During anal intercourse, the rectal mucosa is relatively dry, which is very easy to form damage and bleeding. If one party is a AIDS patient, the virus will enter the blood directly from the damaged area of the anus or rectal mucosa, increasing the risk of AIDS infection for men who are homosexual.
- Promiscuity, having multiple sexual partners
Having multiple sexual partners can increase the risk of infection with AIDS or other sexually transmitted diseases.
- Suffering from sexually transmitted diseases
Conditions such as syphilis, genital warts, or active herpes can be easily transmitted through unprotected sexual intercourse with HIV infected individuals due to the presence of skin lesions on the reproductive organs.
- Drug abuse
If needles, syringes, cotton swabs, or other injection equipment are shared, the risk of HIV infection will increase.
- Other factors
When female patients have gynecological diseases such as pelvic inflammatory disease, the vaginal mucosa may become congested and swollen, and during sexual activity, it is easy to damage and cause mucosal rupture and bleeding, leading to HIV transmission.
symptom
executive summary
The average incubation period is 9 years, which can be as short as several months or as long as 15 years. It is a long and complex process from initial HIV infection to the final stage. At different stages of the whole process, HIV related clinical manifestations are diverse. According to China’s standards and guidelines for diagnosis and treatment of AIDS, AIDS is divided into acute stage, asymptomatic stage and AIDS stage.
Typical Symptoms
- Acute phase
Usually occurring within 6 months of initial HIV infection, some infected individuals may experience clinical symptoms of HIV viremia and acute immune system damage. This can be seen as an early stage after HIV infection, marking the beginning of active replication of the virus in the body and its initial impact on the host immune system.
At this stage, most patients have mild clinical symptoms that persist for 1-3 weeks before improving. The most common clinical manifestation is fever, which may be accompanied by general discomfort, headache, night sweats, nausea, vomiting, diarrhea, sore throat, muscle pain, joint pain, rash, lymphadenopathy, and neurological symptoms. HIV RNA and P24 antigen can be detected in this serum. HIV antibodies do not appear until several weeks after infection. The CD4+lymphocyte count temporarily decreases, while the CD4/CD8 ratio is inverted. Some patients may have mild leukopenia and/or thrombocytopenia and liver dysfunction.
- Asymptomatic period
It can enter this phase from the acute phase, or directly enter this phase without obvious acute symptoms. The duration of this period is generally 4-8 years, and its length is related to factors such as the number of infected viruses, virus types, infection routes, individual differences in immune transformation, nutrition, hygiene conditions, and lifestyle habits. During this period, due to the continuous replication of HIV in infected individuals, the immune system is damaged and the CD4+lymphocyte count gradually decreases, making it contagious.
- AIDS
The final stage after HIV infection. The CD4+lymphocyte count of the patient decreased significantly, to around 200/mm3, and the HIV plasma viral load increased significantly. The main clinical manifestations of this period are HIV related symptoms, various opportunistic infections, and tumors.
(1) HIV related symptoms
The main symptoms are fever, night sweats, and diarrhea that persist for more than one month; Weight loss of more than 10%. Some patients present with neurological and psychiatric symptoms, such as memory loss, mental apathy, personality changes, headaches, epilepsy, and dementia. In addition, persistent systemic lymph node enlargement may occur, characterized by: ① enlargement of two or more lymph nodes in areas other than the groin; ② Lymph node diameter ≥ 1cm, no tenderness, no adhesion; ③ Duration of more than 3 months.
(2) Various opportunistic infections and tumors
① Respiratory system: Pneumocystis pneumonia caused by Pneumocystis aeruginosa is characterized by chronic cough, fever, cyanosis, decreased blood oxygen pressure, and few pulmonary rales. Chest X-ray shows interstitial pneumonia. Hexamethylenetetramine silver staining or modified methylene blue staining can quickly detect Pneumocystis aeruginosa in sputum or tracheal lavage fluid. CMV、MTB、 Avian mycobacteria, Candida, and Cryptococcus often cause pulmonary tuberculosis, recurrent bacterial infections, and fungal pneumonia. Kaposi’s sarcoma also frequently invades the lungs.
② Central nervous system: Cryptococcus neoformans meningitis, tuberculous meningitis, toxoplasmosis encephalopathy, various viral meningitis.
③ Digestive system: Candida albicans esophagitis, cytomegalovirus esophagitis, enteritis, Salmonella, Shigella, Campylobacter jejuni, and Cryptosporidium enteritis; Symptoms include thrush, esophagitis or ulcers, swallowing pain, burning sensation behind the sternum, diarrhea, weight loss, infectious perianal inflammation, proctitis. Fecal and endoscopic examinations can help diagnose elevated serum transaminase levels caused by cryptosporidium, hepatitis virus, and CMV infections. I may have opportunistic infections and tumors of the gallbladder.
④ Oral: thrush, tongue furry leukoplakia, recurrent oral ulcers, gingivitis, etc.
⑤ Skin: Herpes zoster, contagious molluscum, genital warts, fungal dermatitis, and onychomycosis.
⑥ Eye: CMV retinitis and toxoplasmosis retinitis, characterized by flocculent white spots in the fundus. Eyelids, ophthalmic glands, lacrimal glands, conjunctiva, and iris are often invaded by Kaposi’s sarcoma.
⑦ Tumors: malignant lymphoma, Kaposi’s sarcoma, etc. Kaposi’s sarcoma invades the skin and oral mucosa of the lower limbs, and may present with purple red or dark blue infiltrates or nodules that merge into patches, surface ulcers, and spread outwards. This malignant lesion can occur in lymph nodes and internal organs.
complication
- Opportunistic infection
(1) Protozoan infection
① Toxoplasma gondii disease: often accompanied by headaches, fever, meningitis, choroiditis, etc. The diagnosis mainly relies on detecting anti Toxoplasma IgM antibodies (+) in the blood or typical circular lesions on head CT.
② Cryptosporidium enteritis: mainly characterized by diarrhea, watery stools, sometimes in large quantities, can cause dehydration and electrolyte imbalance.
(2) Bacterial infection
Gram positive cocci and Gram negative bacilli are often secondary to some complications, the most common of which are Mycobacterium tuberculosis and Mycobacterium avium. Clinical pulmonary tuberculosis progresses rapidly, with cavities and positive sputum bacteria visible. Treatment is difficult, and systemic disseminated tuberculosis can also occur.
(3) Fungal infection
① Common oral candidiasis, as well as esophageal, tracheal, or colonic candidiasis.
② Pneumocystis carinii pneumonia: In recent years, it has been found that the DNA of Pneumocystis carinii is more like a fungus, so it is classified as a fungal infection. The main symptoms are low-grade fever, dry cough with less phlegm, worsening of difficulty breathing after physical activity, mild cyanosis during physical examination, occasional sputum sounds in both lungs, rarely heard wet rales, significant decrease in blood gas oxygen pressure, increased lung markings or patchy shadows on chest X-rays, and in severe cases, large fused shadows in both lungs that appear as ground glass. If fiberoptic bronchoscopy lavage fluid examination is performed, card shaped pulmonary cysticercus trophozoites and cysts can be found.
③ Cryptococcus meningitis and systemic infections caused by tissue plasma bacteria or penicillin have also been frequently reported.
(4) Viral infection
Visible infections include hepatitis B virus (HBV), hepatitis C virus (HCV), herpes simplex virus (HSV), herpes zoster virus (HZV), cytomegalovirus (CMV), and EB virus.
- Malignant tumor
(1) Kaposi’s sarcoma: can be seen on the skin or mucosa, including the lungs, esophagus, and gastrointestinal tract, and diagnosis requires pathological examination by biopsy.
(2) Lymphoma: It often has persistent fever and enlarged lymph nodes throughout the body, and diagnosis also depends on biopsy and pathological examination.
- Common malnutrition
Due to excessive consumption of various infections or tumors caused by fever, diarrhea, and loss of appetite in patients, it can lead to malnutrition and even cachexia over time.