Pasteurella multocida osteomyelitis is an uncommon but serious infection of the bone caused by Pasteurella multocida, a facultative anaerobic, Gram-negative coccobacillus. This zoonotic pathogen is part of the normal oral flora of domestic animals, particularly cats and dogs. Human infection usually occurs following bites, scratches, or licks on broken skin, leading to local tissue infection
Pasteurella multocida endocarditis represents a rare but increasingly recognized form of zoonotic infective endocarditis. This Gram-negative, facultatively anaerobic coccobacillus is commonly found in the oropharyngeal flora of domestic animals, especially cats and dogs. Human infections typically follow animal bites, scratches, or close contact. Though commonly associated with soft tissue infections, Pasteurella multocida can invade deeper
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired hematologic disorder marked by chronic intravascular hemolysis, bone marrow failure, and a heightened risk of thrombosis. It stems from a somatic mutation in the PIGA gene in hematopoietic stem cells, resulting in defective glycosylphosphatidylinositol (GPI)-anchored proteins that regulate complement activity. This deficiency renders red blood cells highly
Paratyphoid fever is a systemic bacterial infection caused by Salmonella enterica serovars Paratyphi A, Paratyphi B, and Paratyphi C. It is part of the enteric fever complex, closely related to typhoid fever, but is generally considered less severe. Paratyphoid fever remains a significant public health concern in many low- and middle-income countries, particularly where sanitation
Parathyroid hyperactivity, typically associated with primary hyperparathyroidism, results from excessive secretion of parathyroid hormone (PTH). Accurate localization of hyperfunctioning parathyroid tissue is essential to guide surgical intervention, particularly for patients undergoing minimally invasive parathyroidectomy. The success of treatment depends heavily on precise preoperative and intraoperative identification of the overactive gland(s). Pathophysiology of Parathyroid Hyperactivity The
Parathyroid carcinoma is a rare but aggressive endocrine malignancy originating from the parathyroid glands. It accounts for less than 1% of primary hyperparathyroidism cases yet is a critical differential diagnosis in patients presenting with severe hypercalcemia. The excessive secretion of parathyroid hormone (PTH) leads to markedly elevated serum calcium levels, posing life-threatening systemic complications. Unlike
Parasitic infections remain a significant global health concern, especially in regions with limited access to clean water, sanitation, and healthcare. A parasitic infection occurs when a parasite—an organism that lives on or inside a host—invades the human body and disrupts normal physiological functions. These organisms derive nutrients at the host’s expense, often leading to severe
Paragangliomas are rare, typically benign neuroendocrine tumors arising from the paraganglia—a collection of chromaffin cells located outside the adrenal glands. These tumors are closely related to pheochromocytomas, which occur within the adrenal medulla. While many paragangliomas are nonfunctional, some produce catecholamines, leading to significant clinical manifestations. Paragangliomas are classified based on their location: Etiology and
Paracoccidioidomycosis (PCM) is a systemic granulomatous fungal infection caused primarily by Paracoccidioides brasiliensis and Paracoccidioides lutzii. Endemic to Latin America, particularly Brazil, PCM primarily affects the lungs and mucocutaneous membranes and can disseminate to other organs. The disease represents a significant public health issue in rural agricultural regions, where exposure to soil-dwelling fungi is common.
Pancreatic neuroendocrine tumors (pNETs) are a rare subset of pancreatic neoplasms that originate from the hormone-producing islet cells of the pancreas. Unlike the more common pancreatic adenocarcinoma, pNETs tend to have a slower progression but can still be malignant and potentially life-threatening. These tumors can be either functioning, secreting hormones that cause clinical syndromes, or