An internal infection occurs when microorganisms, such as bacteria, fungi, or viruses, invade the body’s tissues or organs and begin to multiply. These microscopic invaders, known as pathogens, can cause harm by damaging cells or releasing toxins. The body’s immune system typically works to eliminate these organisms, but if overwhelmed, the infection can lead to illness. The severity of an internal infection can range from mild to life-threatening, depending on the type of pathogen and the body’s response.
How Internal Infections Occur
Pathogens can enter the body through various routes. Common entry points include the mouth, eyes, nose, or urogenital openings. They can also enter through wounds or bites that compromise the skin barrier. Once inside, these microorganisms can spread through direct contact (e.g., touching an infected surface and then one’s face) or indirect contact (e.g., inhaling airborne droplets from a cough or sneeze).
Contaminated food or water also serves as a common vehicle for pathogens to enter the digestive system. For example, bacteria like Escherichia coli (E. coli) can be present in undercooked meat or unpasteurized juice. Factors that increase susceptibility include a weakened immune system, compromised by conditions like cancer or HIV, or by medications such as chemotherapy or steroids. Pregnancy and being over 60 years old can also increase this risk.
Recognizing the Signs
Internal infections present with both general and localized symptoms. Common systemic symptoms include fever, chills, fatigue, headache, and muscle aches. A fever, specifically a temperature of 37.5°C (99.5°F) or above, can sometimes be the sole indicator of an infection.
Localized symptoms vary depending on the affected organ or system. For instance, a lung infection might present with a cough, shortness of breath, or chest pain, while a gastrointestinal infection could lead to diarrhea, stomach pain, nausea, and vomiting. Skin infections may cause redness, swelling, or pain in a specific area. Timely medical attention is important, as early treatment can prevent an infection from becoming more serious.
Medical Diagnosis and Treatment
Medical diagnosis of internal infections typically begins with a healthcare professional reviewing symptoms and medical history, followed by a physical examination. Various laboratory tests identify the specific pathogen. Blood tests, such as a complete blood count (CBC), can indicate a bacterial infection if there is a high white blood cell count. Other blood tests may detect antibodies or antigens from the pathogen.
Samples of body fluids like urine, sputum, or cerebrospinal fluid, or tissue biopsies, can be collected for culture tests. In these tests, samples are cultured to identify specific bacteria, fungi, or other microorganisms. Imaging scans (X-rays, CT, MRIs) also help diagnose internal infections by providing visual evidence.
Treatment approaches depend on the type of pathogen identified. Bacterial infections are typically treated with antibiotics, which kill or inhibit bacteria. However, some bacteria have developed resistance to antibiotics due to misuse or overuse. Viral infections generally do not respond to antibiotics; they are managed with antiviral medications or supportive care. Fungal infections are treated with antifungal medications, which can be topical, oral, or intravenous for severe cases. Parasitic infections are addressed with anti-parasitic drugs, though resistance is a growing concern.
Preventing Internal Infections
Preventing internal infections involves measures to reduce pathogen exposure and bolster the body’s defenses. Maintaining good hygiene is a primary defense, especially thorough handwashing with soap and water for at least 20 seconds after coughing, sneezing, using the bathroom, or before handling food. If soap and water are unavailable, an alcohol-based hand sanitizer can be used.
Vaccinations offer protection against many bacterial and viral diseases, including tetanus, whooping cough, and certain forms of pneumonia and meningitis. Staying up-to-date with recommended immunizations helps the immune system recognize and fight pathogens. Practicing safe food handling—washing raw meat and produce, separating raw and cooked foods, and ensuring proper cooking temperatures—minimizes foodborne infection risk.
Covering coughs and sneezes with a tissue or into the elbow helps contain respiratory droplets, preventing airborne pathogen spread. Avoiding shared personal items like towels, razors, or eating utensils also reduces person-to-person transmission. Keeping cuts and scrapes clean and covered with sterile bandages prevents bacteria from entering the body.