Dermatology - Hypersensitivity vasculitis
Hypersensitivity vasculitis refers to a diverse collection of vasculitides that are linked to an exaggerated immune response to antigens derived from infectious organisms, medications, or other external or internal causes. Prior to the commencement, a recently introduced medication is a probable cause, along with the possibility of an infection, a recognized vascular/connective tissue disorder, or paraproteinemia. The onset and duration can be categorized as acute (occurring within days, such as in cases of drug-induced or idiopathic causes), subacute (lasting for weeks, particularly in urticarial kinds), or chronic (recurring over a period of years). Systemic vascular involvement mostly affects the kidney, muscles, joints, GI tract, and peripheral nerves. Common symptoms of this condition include itching and a sensation of burning pain. However, it is possible for individuals to have no symptoms at all. In some cases, there may also be other symptoms such as fever, general discomfort, signs of nerve damage in the limbs, abdominal pain due to reduced blood flow to the intestines, joint pain, muscle pain, presence of blood in urine, and involvement of the central nervous system. Abnormalities The defining characteristic is palpable purpura, which refers to visible petechiae that appear as bright red, well-defined macules and papules with a central, dot-like bleeding. This is in contrast to petechiae caused by coagulation abnormalities or thrombocytopenia, which are flat and hence not able to be felt. The lesions are distributed sporadically, either separate or merging together, and are mainly confined to the lower extremities and ankles but can extend to the buttocks and arms. Stasis exacerbates or triggers lesions. The lesions do not lose their color, remaining red, and may even darken to purple or black. During severe inflammation, purpuric papules transform into hemorrhagic blisters, undergo necrosis, and may even develop ulcers. The diagnosis relies on the observation of clinical features and the examination of tissue samples under a microscope. The possible causes of the condition include thrombocytopenic purpura, exanthematous drug eruption accompanied by thrombocytopenia, disseminated intravascular coagulation with purpura fulminans, septic vasculitis (such as rickettsial spotted fevers), septic emboli (related to infective endocarditis), bacteremia (including disseminated gonococcal infection and acute/chronic meningococcemia), pigmented purpura, and other noninfectious vasculitides. Administer antibiotics to patients who develop vasculitis subsequent to a bacterial infection. Administer prednisone to patients with moderate-to-severe disease, along with cytotoxic immunosuppressants such as cyclophosphamide or azathioprine, or cyclosporine and intravenous immunoglobulin for severe disease.
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Dermatology - Macule
The term "macule" is derived from the Latin word for "spot." A skin eruption characterized by flat, discolored patches is referred to as a macular exanthem. A macule is a defined region on the skin that exhibits a shift in color without any raised or sunken areas.Macules are characterized by their flat nature and lack of palpability. Macules might have distinct boundaries (sharply defined) or spread out. • Macules can vary in size or color. Macules can have pigmentation in shades of brown, black, or blue, or they might be skin-colored (amelanotic) or red. Diagnosis Diascopy, which involves applying pressure from a glass slide on the edge of a red macule, allows for the detection of red blood cells. If the redness persists when pressure is applied to the slide, the lesion is classified as purpuric, indicating that it is caused by the leakage of red blood cells. Conversely, if the redness vanishes, the lesion is attributed to vascular dilation. Infectious Diseases and Microbiology - Schistosomiasis ( Schistosoma mansoni) Schistosomiasis is a parasitic disease. Schistosoma mansoni is a nonsegmented flatworm or fluke belonging to the Trematode class which causes schistosomiasis. There are three prevalent species of human schistosomes: S mansoni, S japonicum, and S haematobium. Snails serve as intermediary hosts. Humans are the ultimate hosts. Cercariae enter the human skin, mature into adults, and deposit eggs that are excreted in urine (haematobium) or stool (mansoni and japonicum). The regions where the disease is commonly found are Africa, South America, the Middle East, the West Indies, and Puerto Rico for S. mansoni; China, Japan, and the Philippines for S. japonicum; and Africa, the Middle East, and India for S. haematobium. Swimmer's itch occurs when cercariae from avian and mammalian species of Schistosoma penetrate the skin. Following the entrance of cercariae into the skin, a temporary rash characterized by itching and the presence of little raised bumps may develop. Acute symptoms consist of elevated body temperature and shivering. The prevalence of chronic diseases in adults varies depending on their geographical region. Schistosoma mansoni and Schistosoma japonicum result in abdominal pain, bloody diarrhea, and hepatosplenomegaly. Schistosoma haematobium induces the symptoms of blood in urine, painful urination, and blockage, and is linked to bladder cancer. Following the invasion of the skin, the organism infiltrates the bloodstream and then travels to the lungs. Each of the three primary human schistosome parasites resides within a specific region of the venous plexus that drains either the intestines or bladder, depending on the particular species. Specifically, S mansoni inhabits the mesenteric veins of the colon, S japonicum resides in the mesenteric veins of the small bowel and colon, and S haematobium is found in the veins surrounding the bladder and pelvic organs. Additionally, all three parasites are capable of producing eggs. The pathogenesis of this condition arises from the immune system's reaction to the eggs, leading to the formation of abscesses, fibrosis, granulomas, and scarring. The eggs secrete hydrolytic enzymes that degrade tissue and facilitate the shedding process. The presence of eggs in pee or stool is a distinctive trait. Praziquantel is an effective therapy option. Prevention entails implementing effective waste management practices, refraining from swimming in freshwater bodies located in regions with a high prevalence of the disease, and eliminating snail populations. Infectious Diseases and Microbiology - Cestode induced Diarrhea ( Hymenolepis nana)
Cestode-induced Diarrhea is caused by Hymenolepis nana, a type of segmented flatworm known as a dwarf tapeworm. This tapeworm is the tiniest among adult tapeworms. The complete life cycle occurs within people. The etiology of this condition involves humans as the definitive host, with no necessary intermediate hosts. The mode of transmission is through the ingestion of fecal matter. Particularly common among children. Hymenolepis nana is a prevalent tapeworm infection, particularly in the southeastern region of the United States. Infections typically do not show symptoms when there are just a few worms present, but as the number of worms increases, gastrointestinal symptoms become more apparent. Eggs are highly contagious. After being consumed, the larvae undergo development and attach themselves to the intestine. The adult worms are of diminutive size, measuring 2–5 cm in length, and generate eggs that are excreted in feces. The host can experience autoinfection, leading to a significant increase in the number of worms, often reaching several hundred. Detection of H nana eggs (including a six-hooked embryo) in stool is indicative of the presence of the parasite. The standard course of treatment usually consists of praziquantel. The most effective approach to prevention is implementing measures that eradicate the transmission of fecal matter through the mouth. Infectious Diseases and Microbiology - Diphyllobothriasis ( Diphyllobothrium latum) Diphyllobothrium latum is a type of cestode, which is a segmented flatworm. It is commonly known as the broad fish tapeworm. The strobila consists of one or many hermaphroditic proglottids. Humans are the primary host. D latum utilizes two consecutive intermediate hosts: a freshwater copepod known as Cyclops and a freshwater fish. Infection occurs as a consequence of consuming freshwater fish that is undercooked, pickled, or uncooked. The majority of infections do not show any symptoms; nevertheless, when there is a scarcity of vitamin B12, it can cause a shortage in B12, leading to megaloblastic anemia and a range of neurological symptoms. Adult tapeworms maintain their attachment to the intestine through the scolex and can reach a length of up to 13 meters. The eggs of D latum have an elongated shape and possess a lidlike operculum. The proglottids exhibit a greater width compared to their length, featuring a uterine branch pattern arranged in a rosette formation. Praziquantel is administered for therapeutic purposes. Prevention include refraining from consuming undercooked fish and implementing precautions to avoid contamination of freshwater lakes by human feces. Infectious Diseases and Microbiology - Taeniasis (Beef Tapeworm ) Beef tapeworm infection, or taeniasis Beef tapeworms, or Cestodes, are known by the name Taenia saginata. One or more hermaphrodite proglottids can be found in Strobila. Cattle are the intermediate host; humans are the final host. When undercooked beef is consumed, infections spread to humans. T saginata does not cause cysticercosis. Adult tapeworm infections are asymptomatic or present with minor gastrointestinal symptoms. The scolex is how adult tapeworms stay connected to the intestine, and they can reach lengths of up to 10 meters. It is diagnostic to see proglottids with 15–30 uterine branches or eggs in the perianal area or feces. Praziquantel is frequently used as a medication. To prevent infection in animals, prevent undercooked beef and dispose of human waste properly. Infectious Diseases and Microbiology - Cysticercosis with Neurological Involvement (Taenia solium )1/27/2024 Infectious Diseases and Microbiology - Cysticercosis with Neurological Involvement (Taenia solium ) Neurological involvement in cysticercosis Taenia solium is a type of segmented flatworm known as a Cestode. It is commonly referred to as a pork tapeworm. The strobila consists of one or many hermaphroditic proglottids. Humans serve as the primary host, while pigs act as the intermediary host. Pigs consume eggs, and the embryo penetrates the intestinal wall, enters the bloodstream, and disseminates to skeletal muscle. Infection in humans occurs when they consume undercooked pork that is contaminated with encysted larvae. Tapeworms mature within the gastrointestinal tract and release proglottids that contain eggs into the feces. The transfer of eggs by the oral route, either from contact with an individual carrying the adult tapeworm or through self-infection, leads to the development of cysticercosis. Adult tapeworm infections typically result in minor gastrointestinal symptoms or show no symptoms at all. Cysticercosis is a grave condition that results in the development of cysticerci in many human tissues, such as the eye, brain, muscle, and lungs. The symptoms of cysticerci might differ according on their location, but may encompass meningioencephalitis, seizures, and other neurological signs. Adult tapeworms remain connected to the intestine through the scolex and can reach a length of up to 5 meters. Without receiving treatment, they have the potential to live for several decades. In cysticercosis, the eggs are consumed and release oncospheres in the colon, which then go to other tissues in the body. The presence of proglottids displaying 5-13 uterine branches or eggs in feces or the perianal region is indicative and can be used for diagnosis. Medical assessment Cysticerci are frequently detectable using X-ray, CT, or MRI imaging due to their tendency to undergo calcification. Praziquantel is used to treat adult tapeworm infections. The treatment for cysticercosis involves the surgical removal of the cysts and/or the administration of praziquantel or albendazole. Prevention entails refraining from consuming undercooked pork and implementing hygienic practices to prevent the transmission of diseases by the oral ingestion of fecal matter. Infectious Diseases and Microbiology - Toxocariasis / Visceral Larva Migrans (Toxocara canis and Toxocara cati ) Toxocariasis, also known as Visceral Larva Migrans Toxocara canis and Toxocara cati are both species of Nematode, which are a type of roundworm. The tissue manifestations are referred to as Visceral larva migrans. Humans are terminal hosts. Dogs (T canis) and cats (T cati) serve as decisive hosts. Dogs and cats excrete Toxocara eggs in their feces. Humans, particularly youngsters aged 1-4 with a background of pica, acquire the infection by consuming eggs. A significant number of persons are without symptoms. The symptoms of larval infestation might vary depending on their location. Some individuals may have gastrointestinal pain, rash, fever, enlarged liver, retinal involvement resulting in blindness, or manifestations affecting the heart, respiratory system, or central nervous system. Upon ingestion, eggs give rise to larvae that then move to various organs, such as the lungs, liver, kidney, heart, eyes, muscle, and central nervous system (CNS). The larvae undergo encystation, transforming into second-stage larvae. The larvae migration results in the formation of tracts characterized by hemorrhagic necrosis, as well as infiltration of eosinophils and lymphocytes. Granulomas can form around deteriorating larvae. The development of the disease is caused by the intensity of the inflammation and the specific site and quantity of the deceased larvae. Elevated levels of hypereosinophilia and hypergammaglobulinemia, along with increased titers of isohemagglutinin against the A and B blood group antigens, are indicative of a probable infection. The diagnostic process entails serologic testing, analysis of tissue biopsies for larvae, and evaluation of clinical signs and symptoms. Stool samples can be analyzed to detect eggs in pets. Mebendazole and albendazole are utilized for therapeutic purposes. Prevention entails the practice of deworming pets and maintaining proper hygiene for pets. Infectious Diseases and Microbiology - Onchocerciasis/ River Blindness (Onchocerca volvulus )1/27/2024 Infectious Diseases and Microbiology - Onchocerciasis/ River Blindness (Onchocerca volvulus ) Onchocerciasis, often known as River Blindness, is a parasitic disease. Onchocerca volvulus is a parasitic roundworm belonging to the nematode family. Transmitted by the intermediary of an arthropod vector. The Simulium black fly, which reproduces in swiftly moving streams and rivers, serves as the carrier of the disease. Geographical regions where a certain disease is regularly seen include equatorial Africa and Central and South America. The clinical causative agent of river blindness. The symptoms encompass a skin rash, itching, reduced elasticity in the subcutaneous tissue (resulting in the formation of enormous skin folds), and varying degrees of visual impairment, ranging from partial to complete blindness. Upon entering the bite wound, the larvae proceed to travel towards the subcutaneous tissue, where they undergo development and transform into adults within fibrous nodules located beneath the skin. Once the worms reach maturity, they create microfilariae that travel through the subcutaneous tissue and skin. These microfilariae can be consumed by biting black flies, which helps to spread the infection. The pathogenesis occurs due to an exaggerated immune response to the antigens of the parasite and the inflammation caused by the movement of the larvae. Microfilariae in ocular structures cause photophobia and inflammation in several parts of the eye, including the cornea, iris, ciliary body, retina, choroids, and optic nerve. Untreated illness can lead to blindness. Microfilariae are observable in skin biopsies and can also be seen through slit-lamp examination of the anterior chamber of an affected eye. The treatment consists of surgically extracting mature cutaneous nodules along with the administration of ivermectin (to eliminate microfilariae). Prevention encompasses the implementation of infection control strategies. Administering prophylactic ivermectin treatment in places where a disease is prevalent can decrease the number of microfilariae present. Infectious Diseases and Microbiology - Filariasis (Wuchereria bancrofti) Lymphatic obstruction caused by filariasis. Wuchereria bancrofti, together with Brugia malayi and B timori, are nematodes that reside in the tissues and belong to the filarial group of roundworms. Transmitted by an arthropod carrier.The transmission of W bancrofti can be facilitated by several mosquito genera, including Anopheles, Culex, Aedes, and Mansonia. W bancrofti is prevalent in numerous regions in Africa, Asia, South America, and the southern Mediterranean.The majority of filarial infections do not exhibit any symptoms. The initial signs of the condition include fever, chills, muscle pain, and lymphadenitis. Chronic inflammation causes blockage of the lymphatic system, which can lead to elephantiasis in extreme instances. Additionally, secondary bacterial infections may arise. After being bitten by an infected mosquito, the larvae enter the skin and travel through the lymphatic system to the nearby lymph nodes. Following an extended period of incubation lasting between 6 months and a year, the larvae undergo maturation and transform into adult organisms. These adults then generate microfilarial larvae which travel into the bloodstream during nighttime. The microfilariae can be consumed by a feeding mosquito to continue the transmission process. The adult versions have the ability to endure for a period of up to ten years. Chronic disease arises due to inflammation in the lymphatic system, leading to blockage and swelling. Recurring infections escalate the number of worms present, resulting in progressively severe symptoms of the condition. The microfilariae undergo nocturnal migration into the bloodstream. The thick-smear blood examination should be conducted using samples collected specifically between the hours of 10 pm and 4 am. Diethylcarbamazine is employed for the eradication of adult worms and microfilariae. Obstructions may require surgical intervention for relief. Prevention entails implementing measures to control mosquitoes, as well as employing personal barriers and repellents to minimize exposure. In recent times, a strategy known as community-wide treatment has been implemented to mitigate the spread of diseases in places with a high risk of transmission. |
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