MedUrgent

AMOEBIC DYSENTRY  Dysentery is defined as passage of small frequent motions of 3-20/day, containing blood and mucus. Its incubation period is unknown, and could range from a few days to several years. It may be divided into 3 main varieties depending on the severity of the infection, and the nutritional status of the host. These categories are:  1. Mild; it is of insidious onset and the patient is well nourished, and there is usually constipation rather than diarrhea. A few dysenteric motions may occur. Ulcers are few, and the trophozoites are scanty.  2. Moderate: The patient feels unwell, but is not forced to stay in bed, hence, the name (walking dysentery). Motions are 5-10 times a day, and contain mucus and blood. In the mild and moderate forms, tenderness over the transverse colon may be elicited; as well as tenderness over the right iliac fossa. Fever, abdominal pain and tenesmus are not features of the above two categories.  3. Severe: This has a rapid onset...

  AMOEBIASIS According to the WHO definition, it is a condition in which the protozoan parasite Entemoeba histolytica is harbored by some patients regardless of their symptoms. Geographically, it is a world-wide disease, although it is more prevalent in the tropics and sub-tropics. It is primarily a parasite of the large bowel where it mostly affects the cecum and ascending colon and in severe infections, it extends into the ilium and appendix. Poor sanitation and overcrowding account for the occurrence of epidemics of amoebic dysentery. More severe infection is seen in pregnant women, younger children, immunocompromised patients, and those on corticosteroid medications. Cysts transmit the disease and are resistant to drying, cold and routine chlorination of water. Trohozoites are not infective as they are destroyed by the acid in the stomach. AETIOLOGY It is caused by Entemoeba histolytica, a protozoan which may persist in a cystic form in chronic carriers but may become vir...

GIARDIASIS   Giardia is a flagellate protozoan which has both a trophozoite and a cystic form. It inhabits the duodenum and jejunum and it is one of the most common parasites in man worldwide. In endemic situations children may suffer from malabsorption. It infests the upper small bowel causing travelers' diarrhea'. The parasite has a sucking disc by which it attaches itself to the mucosa of the small intestine. It has 4 pairs of flagellae and multiplies by binary fission. The cyst is oval and has 4 nuclei. They are infectious as soon as they hatch and may ex-cyst in the upper gastrointestinal tract when they can cause acute diarrhea. Transmission Man is the only source of infection. It is more common in children than adults, and the spread is by the oral-fecal route through contaminated food and water with cysts. PATHOLOGY   Exposure to G. Lamblia is variable depending upon variations in load of the parasite and host factors. The disease may be asymptomatic or present...

BACILLARY DYSENTERY SHIGELLOSIS   It is caused by a group of Shigella organisms (gram -ve non motile rods). There are 4 groups of Shigella and about 40 types. Shigella dysentriae and S. flexeneri are commonly found in tropical countries, while S. sonnei is most frequently isolated in temperate climates. The 4 main groups are: 1- Shigella dysentriae (10 serotypes have been described including Shigella shiga) 2-Shigella flexeneri: (6 serotypes) 3- Shigella boydeii 4- Shigella sonnei Man is the major reservoir and transmission from person to person occurs by oro-faecal route through infected hands when personal hygiene is poor, from contaminated food or drink or by vectors such as house flies. Infection is transmitted from infected cases who continue to shed bacilli for 2 - 6 weeks; convalescent patients and chronic carriers. Infants, young children and old people are more likely to be infected especially with the severe form of the disease. PATHOGENESIS On entering ...