Medicine Hack

  DEFINITION  Emphysematous pyelonephritis is an acute necrotizing infection characterized by gas formation. It is characterized by the presence of gas in and around the kidney.   ETIOLOGY   E. coli (58%) and K. pneumoniae (21%) are the organisms most commonly isolated. Clostridium and Enterobacter spp may also be responsible, 7% each.   RISK FACTORS   1) Diabetes mellitus (70-90%)- usually patients with poor glucose control. High levels of glucose in the urine serve as a substrate for these bacteria and large amounts of gas are generated through natural fermentation 2) Obstruction (25-40%)- it is another common predisposing factor for emphysematous pyelonephritis. For non-diabetics, protein fermentation is a proposed source of gas formation.  CLINICAL FEATURES  7% of cases may be asymptomatic. If symptomatic, patients may complain of pneumaturia, irritative lower tract voiding symptoms, flank pain or may present in a severe septic condition with an acute abdomen and hig

 DEFINITION  Torsades de pointes is a polymorphic ventricular tachycardia that occurs frequently in cases of QT interval prolongation. This can be due to congenital or acquired Long QT interval syndrome. It is characterized by a progressive change of the electrical axis, typically rotating 180 degrees in approximately 10 to 12 cycles and the amplitude, as though the depolarization and repolarization of the ventricle was turning on a point. This results in the characteristic sinusoidal twisting of the peaks of the QRS complexes around the isoelectric line of the recording.  EKG  The tachycardia rate typically is in the range of 150 to 300 beats/min. It is usually a self-limiting arrhythmia that spontaneously dies out after a few tens of cycles and only in a minority of cases that it degenerates into ventricular fibrillation and can lead to sudden cardiac death. Drugs that can prolong the QT interval and induce Torsades de pointes are: It can also be caused by ele

Each muscle fibre is closely surrounded by connective tissue. This acts as a support for the muscle fibres and unites them to each other. 1) Each muscle fibres is surrounded by delicate connective tissue that is called the endomysium . 2) Individual fasciculi are enclosed by a stronger sheath of connective tissue called the perimysium . 3) The entire muscle is surrounded by connective tissue called the epimysium . This is illustrated by the schematic diagram below. 1= perimysium, 2= endomysium, 3= fasciculus. At the junction of a muscle with a tendon, the fibres of the endomysium, the perimysium and the epimysium become continuous with the fibres of the tendon. First published on: 27 December 2016

  DEFINITION  Chronic sinusitis refers to inflammation the paranasal sinuses for a period of at least 12 weeks. The most important cause of chronic sinusitis is failure of acute infections to resolve.   PATHOPHYSIOLOGY  Acute infection destroys the normal ciliated epithelium, thus impairing drainage from the sinuses. There is pooling and stagnation of secretions in the sinuses which favours infections. Persistence of infection causes mucosal changes, such as loss of cilia, edema and polyp formation. We eventually have a vicious cycle.   CLINICAL FEATURES  Patients may complain of blocked nose, runny nose, headache and a reduced sense of smell (hyposmia). Foul-smelling discharge suggests anaerobic infection. Some people will also have nasal polyps.   TREATMENT  1) We should always search for underlying aetiological factors which obstruct sinus drainage and ventilation. 2) A work-up for nasal allergy may be required. 3) Culture and sensitivity of sinus discharge helps in t

  DEFINITION   It is an upper respiratory tract illness that comprises of rhinorrhea and nasal obstruction as the main symptoms.   EPIDEMIOLOGY   5- 7 times/ year in children and 2-3 times/ year in adults. most commonly seen between the early fall and late spring in temperate climates. Transmission of the virus may occur via direct contact, large-particle aerosol, or small-particle aerosol.   MICROBIOLOGY   The rhinoviruses are usually responsible for the majority of cases. Coronavirus, respiratory syncytial virus and metapneumovirus may also be associated with the common cold syndrome.   DIAGNOSIS   The diagnosis of the common cold is a clinical diagnosis. Polymerase chain reaction assay can determine the responsible pathogen but this is rarely useful in the management of the patient.   THERAPY   Management is mainly directed towards the bothersome symptoms as no specific antiviral agents are useful in the treatment. First published on: 10 June 2016

 PENETRATION  Penetration is one of the five technical factors that help you in determining whether a radiograph is technically adequate.  ADEQUATE PENETRATION  If a frontal chest radiograph is adequately penetrated, you should be able to see the thoracic spine through the heart shadow. In the radiograph above, we can see the thoracic spine through the heart shadow (solid white line).  UNDER PENETRATION  It means that the penetration is inadequate. The radiograph will appear as too white. We will not be able to see the thoracic spine through the heart. This can lead us into making interpretation errors. 1) The pulmonary markings may appear more prominent and these can be mistaken for being due to a congestive heart failure or pulmonary fibrosis. 2) The left lung base will appear opaque thus obscuring the left hemidiaphragm. This can mimic or hide a true disease in the left lower lung field e.g. left lower lobe pneumonia or left pleural effusion. To avoid these misin