Endemic pellagra in northern Portugal

Giardiasis is a globally prevalent intestinal infection caused by the protozoan parasite Giardia duodenalis (also known as G. lamblia or G. intestinalis). This flagellated protozoan is the most frequently identified intestinal parasite in the United States and worldwide. Transmission primarily occurs via the fecal-oral route, with infection arising from ingestion of water or food contaminated with cysts. Individuals in low-resource settings, international travelers, outdoor enthusiasts, daycare...

DefinitionHepatic encephalopathy is a reversible neurologic syndrome that results from advanced liver dysfunction or portosystemic shunting. It leads to disturbances in cognition, behavior, and motor function due to the brain’s exposure to gut-derived toxins that the liver fails to detoxify.EtiologyThis condition develops either in the setting of acute fulminant hepatitis or progressively during chronic liver disease, such as cirrhosis and portal hypertension. Portosystemic shunting—including...

Leishmaniasis is a protozoal disease caused by species of the genus Leishmania and transmitted through the bite of infected female sandflies. The parasite exists in two principal morphological forms during its life cycle. A sandfly acquires intracellular amastigotes from an infected reservoir host, such as a dog. Within the sandfly, these forms differentiate into motile, flagellated promastigotes. During a subsequent blood meal, promastigotes are injected into the human host, where they...

Vitamins, derived from the Latin word for life, are essential organic substances required in small quantities for optimal growth and overall well-being. Unlike other organic nutrients, vitamins don't act as sources of energy or building materials but rather facilitate these nutrients' utilization by the body. Vitamins are predominantly coenzymes, assisting enzymes in specific chemical actions, like the oxidation of glucose for energy involving B vitamins. Most vitamins are not produced in our...

The pathophysiology of gastritis begins with the colonization of the stomach lining by Helicobacter pylori (H. pylori). This bacterium spreads mainly via the oral-oral route through saliva or shared utensils, and can also be transmitted in overcrowded or unhygienic environments through contaminated water, despite its brief survival outside the body.ColonizationOnce ingested, H. pylori enters the stomach and begins colonization by navigating through the mucus layer lining the stomach wall. It...

Gastritis is marked by disruption of the mucosal barrier that usually protects the stomach tissue from digestive juices and manifests in acute and chronic forms.
In acute gastritis, the gastric mucosa becomes swollen and red and undergoes superficial erosion. Superficial ulceration may lead to bleeding.
In chronic gastritis, persistent or repeated insults lead to chronic inflammatory changes and, eventually, thinning or atrophy of the gastric tissue.
Gastritis can stem from various causes, each...