Medicine Hack

Bilevel noninvasive ventilation provides: 1) IPAP - inspiratory positive airway pressure and 2) EPAP - expiratory PAP at two different levels. This is typically delivered with a tight fitting nasal or face mask which allows for the development of positive airway pressure. The noninvasive therapy should be initiated as early as possible in case of respiratory failure and is best used for short term. "Delta PAP" is the difference between IPAP and EPAP. It directly correlates with the tidal volume delivered. If the "delta PAP" is larger then the tidal volume will be larger and hence it will provide a better alveolar ventilation.  INITIAL SETTINGS  It is quite safe to start the following initial settings: 1) EPAP 3 to 5 cm H2O (2 - 4 mm Hg) – It can be increased to around 10 cm H2O if ever the oxygenation remains inadequate tidal volume. 2) IPAP 8 to 12 cm H2O (6 - 9 mm Hg) – This can be increased in increments of 2 cm H2O as tolerated by the patient, to a maxim...

  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 ...

 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 al...

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 se...

  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 usefu...

 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...

 DEFINITION  Obesity is a state of excess adipose tissue mass. It is often viewed as equivalent to an increased body weight. This is not true because muscular individuals may have increased body weight but are not obese. Weight follows a continuous distribution pattern in human population. The point at which mortality and morbidity becomes statistically significant is the cut-off to call a patient obese.  METHODS  Various methods have been used to measure obesity. These include: 1) Anthropometry (skin-fold thickness) 2) Densitometry (underwater weighing) 3) CT/MRI 4) Electrical impedance. Still the most common techniques used in clinical practice are: 1) BMI measurement 2) Waist-to-hip ratio measurement.  BMI  It is not an accurate measure of obesity but since it is simple to calculate, it is the most frequently measured parameter. At similar BMI, women usually have more fat than men. When the BMI > 25 Kg/m2, morbidity starts to increa...

 INTRODUCTION  Chronic and excessive use of alcohol is one of the major causes of liver disease. 90% of daily heavy drinkers (>60 g alcohol/day) as well as binge drinkers have fatty liver but a smaller percentage (10-35%) of drinkers progress to alcoholic hepatitis which is a precursor for cirrhosis. The long-term risk is 9 times higher in patients with alcoholic hepatitis compared to those with fatty liver alone. Some population-based surveys have documented that men must drink 40 to 80 g of alcohol daily and women must drink 20 to 40 g daily for 10 to 12 years to achieve a significant risk of liver disease. Liver pathology consists of  3 major lesions  that are progressive and rarely exist in a pure form: 1) fatty liver (usually reverses quickly with abstinence), 2) alcoholic hepatitis and 3) cirrhosis. Prognosis of severe alcoholic liver disease (ALD) is bad. Mortality of patients with alcoholic hepatitis concurrent with cirrhosis id nearly 60...

Times have changed Monsieur Voltaire. Your quote is no longer valid in our "Evidence Based Medicine" world. The quote's accuracy is stunning though if applied to quacks. Our advice to young practitioners : DO NOT BLINDLY FOLLOW WHAT A SENIOR DOCTOR IS DOING. Try to  understand why he did something for that specific problem. Always ask if you do not understand. Article resources: 1)  "Voltaire lisant L’année littéraire de Fréron", huile sur toile de Jacques Augustin Catherine Pajou, 1811 Last reviewed on: 2 September 2015

 Menopause   refers to a point in time that follows 1 year after the permanent cessation of menstrual periods that occurs naturally or is induced by surgery, chemotherapy or radiation. On average, natural menopause occurs between 50 and 51 years (range 45–59) and is part of the process of normal ageing. It has been noted that smoking advances the age of menopause by approximately 2 years. The diagnosis can only be made retrospectively and it is usually preceded by months or years of irregular cycles, that is not associated with some other physiological or pathological causes. If the cessation of menses occurs before the age of 40, then it is referred to as the "Premature ovarian failure". The older terms perimenopause or climacteric generally refer to the time period in the late reproductive years, usually late 40s to early 50s. Characteristically, it begins with menstrual cycle irregularity and extends to 1 year after permanent cessation of menses. The more ...

Introduction: Homocysteine is a sulphur containing amino acid that is produced during the conversion of methionine to cysteine. Hyperhomocysteinemia results when there is an abnormality in the homocysteine metabolism. It is an independent risk factor for stroke, MI, peripheral arterial disease and venous thrombotic disease. Even mild to moderate hyperhomocysteinemia is a significant risk factor for vascular disease. Pathophysiology: The amino acid homocysteine is normally metabolized via the transsulfuration pathway by the enzyme cystathionine-β-synthase (CBS), which requires vitamin B6 as co-factor and via the remethylation pathway by the enzymes methylenetetrahydrofolate reductase (MTHFR), which is folate dependent and methionine synthase, which requires vitamin B12 as co-factor. 1 - Methylenetetrahydrofolate reductase 2 - Methionine synthase Hyperhomocysteinemia can be either: 1) Inherited or 2) Acquired. Inherited Inherited severe hyperhomocyste...

This type of breathing pattern was first described by Adolph Kussmaul, a german physician in 1874. He noticed that his patients with diabetic ketoacidosis had a pattern of breathing which he first labelled as having "air hunger". In the Kussmaul type of breathing, the patient is breathing heavily i.e hyperventilating along with tachypnea. So we will find that the amplitude of the breaths along with the rate will be increased. There is usually no pauses between the breaths. This is not specific for diabetic ketoacidosis. It can also appear in other types of severe metabolic acidoses e.g alcoholic ketoacidosis .

1) Hypotension can occur especially with the intravenous form due to vasodilation and depressed myocardial performance. Long-term oral therapy can also cause depressed contractility but it is unusual. 2) Nausea can sometimes be seen during the loading phase. All we have to do is to decrease the daily dose of the medication. 3) Pulmonary fibrosis is the most serious adverse effect during chronic amiodarone therapy. The fibrosis can be rapidly progressive and fatal. The risk factors include: underlying lung disease, doses of 400 mg/day or more and recent pulmonary insults such as pneumonia. Early amiodarone toxicity can be detected using pulmonary function tests and serial chest X-rays. 4) Other adverse effects that may be seen during long-term therapy include a) corneal microdeposits (which often are asymptomatic), b) hepatic dysfunction, c) vivid and disturbing dreams d) neuromuscular symptoms (most commonly peripheral neuropathy or proximal muscle weakness), e) photosensitiv...

The aminoglycoside group includes gentamicin, amikacin, netilmicin, kanamycin, tobramycin, streptomycin, paromomycin and neomycin. These drugs have a good action against aerobic gram-negative bacteria. They are rapidly bactericidal. Bacterial killing is concentration dependent: The higher the concentration, the greater is the rate at which bacteria are killed. As noted above, some of the names end by -micin while others by -mycin. The reason behind this lies in the origin of the antibiotics. All the antibiotics ending with -mycin are either natural products or semisynthetic derivatives of compounds produced by a variety of soil actinomycetes notably Streptomyces . Those ending with -micin are derived from other actinomycetes e.g Micromonospora.

This procedure is called as Atrial septal defect (ASD) device closure. Transesophageal echocardiography (TEE) is must before procedure for: 1) actual sizing of the defect 2) defining the rims - to hold device in place 3) ruling out anomalous pulmonary venous drainage 4) ruling out significant mitral regurgitation (MR). Intraprocedural TEE is not mandatory. N.B How to distinguish between an ASD device and a patent foramen ovale (PFO) device? Left atrial (LA) disk (green arrow) is larger than Right atrial (RA) disk (yellow arrow), thus it is an ASD device.For a PFO device, RA disk will be larger than LA disk. Further readings:

Historically recognized as “swimming pool” or “fish tank” granuloma. Clinical features: Most infections occur 2 to 3 weeks after contact with contaminated water from one of these sources. The lesions are most often small violet papules on the hands and arms that may progress to shallow, crusty ulcerations and scar formation. Lesions are usually singular. However, multiple ascending lesions resembling sporotrichosis can occasionally occur. Most patients are clinically healthy with a previous local hand injury that becomes infected while cleaning a fish tank or patients may sustain scratches or puncture wounds from saltwater fish, shrimp, fins and other marine life contaminated with M. marinum. Swimming pools seem to be a risk only when non-chlorinated. Diagnosis: Diagnosis is made from culture and histologic examination of biopsy material, along with a compatible history of exposure. Treatment: No treatment of choice is recognized for M. marinum. However, successful treatmen...

COPD exacerbation: Definition: Exacerbation of COPD is defined as an acute episode, characterized by the worsening of the patient’s respiratory symptoms that is beyond normal daily variations and that will eventually lead to a change in his medications. Those having 2 or more exacerbations per year are known as “frequent exacerbators”. Precipitating factors: 1) Respiratory tract infections – viral or bacterial. Most common cause. There may be an increased bacterial burden in the lower airways or new strains of bacteria are acquired during an exacerbation. Commonly implicated viruses include rhinovirus, respiratory syncytial virus, coronavirus and influenza virus. 2) Air pollution. 3) Interruption of maintenance therapy. 4) Unknown causes – 30% cases. Diagnosis: Diagnosis should be made clinically whereby the patient complains of an acute aggravation of his symptoms out of proportion to his day to day variations.  Assessment: Medical history: 1...

Definition: Mild to moderate nausea and vomiting are seen commonly until approximately 16 weeks in most pregnant ladies. Although nausea and vomiting tend to be worse in the morning, thus erroneously termed morning sickness, they frequently continue throughout the day. In some cases, however, it is severe and unresponsive to simple dietary modification and antiemetics. Hyperemesis gravidarum is defined as vomiting sufficiently severe to produce weight loss, dehydration, alkalosis from loss of hydrochloric acid and hypokalemia. Rarely, acidosis from partial starvation and transient hepatic dysfunction develop. Modified PUQE scoring index  (Pregnancy-Unique Quantification of Emesis and Nausea) can be used to quantify the severity of nausea and vomiting.  Epidemiology: There appears to be an ethnic or familial predilection. The hospitalization rate for hyperemesis is around 0.5 to 0.8%. Hospitalization is less common in obese women. In women hospitalized in a previou...