The Catalyst

This is a score to determine the severity of pneumonia. The CURB-65 criteria include five variables(1 point for each variable): C onfusion Blood U rea Nitrogen (BUN) >7 mmol/L  R espiratory rate  ≥30/min B lood pressure, systolic ≤90 mmHg or diastolic  ≤60 mmHg Age ≥ 65 years. Management: 0 point: Treat as an outpatient 1 to 2 points: Admitted to the hospital ≥ 3 points: ICU admission Treatment of Community-Acquired Pneumonia Score-0: The drug of choice is macrolides. Azithromycin 500mg OD or Clarithromycin 500mg BD or Doxycycline 100mg BD. Score 1: Treated with azithromycin 500mg OD+ ceftriaxone 2gm OD Respiratory quinolones (Levofloxacin) are not preferred. Score >2: Azithromycin 500mg OD+ Ceftriaxone 2gm IV OD and specific management. NOTE: In a modified version of the CURB-65, the criteria of blood urea nitrogen has been removed. This elimination removes the need for lab testing.

Type 1 Diabetes Mellitus (T1DM) is a chronic condition that affects the way the body processes glucose (a type of sugar) for energy. It is an autoimmune disease that causes the immune system to attack and destroy the insulin-producing cells (beta cells) in the pancreas. As a result, the body is unable to produce insulin, a hormone that regulates blood sugar levels. Symptoms of T1DM include: Excessive thirst Frequent urination Hunger Fatigue Blurred vision Slow-healing cuts or sores Unexpected weight loss Diagnosis of T1DM is usually done through a combination of blood tests that measure blood sugar levels, glucose tolerance test and antibodies test. T1DM is treated by daily insulin injections or using an insulin pump. A balanced diet, regular physical activity and blood sugar monitoring are also important components of treatment. Complications of T1DM include: Cardiovascular disease Kidney damage Nerve damage Eye damage Foot damage It's important to note that T1DM cann...

Spinal Muscular Atrophy (SMA) is a genetic disorder that affects the motor neurons in the spinal cord , leading to muscle weakness and wasting. It is a progressive disorder that can range from mild to severe, and is caused by a mutation in the SMN1 gene , which provides instructions for making a protein essential for the survival of motor neurons. There are four types of SMA , classified by age of onset and severity: Type 1: Onset in the first 6 months of life, most severe form, and typically leads to death by 2 years of age Type 2: Onset between 7-18 months, moderate severity Type 3: Onset after 18 months, mildest form with individuals having the ability to walk Type 4: Onset in adulthood, least severe form with mild muscle weakness Common symptoms of SMA include: Decreased muscle tone and strength Difficulty with movements such as crawling, walking, head control, and breathing Muscle wasting and atrophy Breathing difficulties Scoliosis (abnormal curvature of the spine) Ther...

Rett syndrome is a rare neurodevelopmental disorder that primarily affects girls and leads to severe impairments in language, communication, and motor skills. It is caused by mutations in the MECP2 gene , which provides instructions for making a protein involved in the regulation of brain function. The symptoms of Rett syndrome typically appear after the first 6-18 months of life and include: Regression of acquired skills such as crawling, walking, and hand use Loss of speech and purposeful hand movements Development of repetitive hand movements such as hand-wringing or hand-clapping Breathing irregularities , including apnea (breathing stops for short periods) Abnormal curvature of the spine (scoliosis) Intellectual disability and impaired social interaction There is currently no cure for Rett syndrome, and treatment is primarily supportive , aimed at managing symptoms and improving quality of life. This may include physical therapy, speech therapy, and medications to m...

Mallampatti classification is a system used to evaluate the visibility of the upper airway during laryngoscopy , which is a procedure used to visualize the vocal cords and upper airway. The classification system is based on the degree of visualization of the soft palate, uvula , and faucial pillars (the structures that support the back of the throat). There are four Mallampatti classes, with class I being the easiest to visualize and class IV being the most difficult . Mallampatti class I: The soft palate, uvula, and faucial pillars are easily visible. This class is considered to have the best airway visibility. Mallampatti class II: The soft palate, uvula, and faucial pillars are partially visible. Mallampatti class III: Only the soft palate is visible. This class is considered to have moderate airway visibility. Mallampatti class IV: The soft palate, uvula, and faucial pillars are not visible. This class is considered to have poor airway visibility. Mallampatti classificatio...

Pericardial abscesses   are a rare and severe condition in which a collection of pus forms within the   pericardium , the sac that surrounds the heart . Epidemiology Pericardial abscesses are rare, with incidence rapidly decreasing after the development of broad-spectrum antibiotics. They can occur in people of any age but are more likely to occur in older adults. The risk of developing a pericardial abscess is increased in individuals with certain underlying conditions, such as infections, trauma, surgery, or other medical conditions, such as cancer or autoimmune disorders. Diagnosis The diagnosis of a pericardial abscess typically involves a combination of imaging tests, such as CT or MRI , as well as laboratory tests to determine the underlying cause.  Pericardiocentesis  may be performed to identify the type of bacteria or other pathogens responsible for the infection . Clinical presentation The clinical presentation of a pericardial abscess may include s...

The perineal body is not a structure but an aggregation of fibromuscular tissue present in the midline at the junction between the anal and urogenital triangle, just ventral to the anal sphincter. It attaches to various muscles in the pelvis: Anterior - superficial and deep transverse perinei, bulbospongiosus Posterior - external anal sphincter  Superior - puborectalis, pubovaginalis and the rectovaginal septum It is continuous with the perineal membrane and the superficial perineal fascia . In males, it continues as the perineal raphe , and in females, it is attached to the posterior commissure and the introitus. The following image shows the perineal body and its muscular attachments. Ten muscles  of the perineum converge and interlace in the perineal body.

Wolff Parkinson White Syndrome (WPW) is characterized by an abnormal accessory pathway in the heart leading to arrhythmias. Pathology: Born with an accessory pathway, the bundle of Kent which connects the atria and ventricle. The electrical impulses from the SA node reach the ventricles earlier via the accessory pathway as there is no AV nodal delay in this pathway. This leads to the preexcitation of the ventricle and initiation of ventricular contraction. This ventricular contraction is prolonged when the impulse via the AV nodal pathway reaches the ventricles. Most common location of the accessory pathway- between the left atrium and free wall of the left ventricle ECG changes:   Shortened PR interval(typically <120 ms) - because of the early initiation of ventricular depolarization. Prolonged QRS duration (total duration >0.12 seconds)- because of the AV nodal impulse reaching the ventricles after the aberrant impulse. Delta waves - slurred upstroke of QRS c...

Vitamin A excess can present as two forms:  Vitamin A toxicity and  Carotenaemia. Hypervitaminosis A results from overconsumption of non-prescription nutritional supplements, prescription medications containing vitamin A derivatives and foods high in vitamin A. Carotenaemia is a benign disorder caused by excessive ẞ-carotene intake. In carotenaemia, carotenes are excreted from sebaceous glands and s weat glands , and ultimately deposit in the stratum corneum. This results in carotenoderma.  Acute vitamin A toxicity manifests with headaches, vision changes, fatigue, anorexia, nausea, vomiting, myalgias and arthralgias. Weight loss can be observed with chronic intoxication. Individuals with chronic hypervitaminosis A have dry and scaly skin, desquamation, cheilitis, alopecia, follicular hyperkeratosis and hyperpigmentation , associated pseudotumor cerebri and skeletal changes (premature closure the epiphyses and pathological bone fractures). Prognosis: Vitamin A to...

Non-contrast CT  is the investigation of choice to identify  acute intracranial bleed  and hence is the  preliminary investigation  in  acute head injury . NCCT is also the investigation of choice for brain hemorrhage and calcification. For all the other neurological lesions, the investigation of choice is MRI. Investigation of choice in Neurology Generally, MRI is considered the best imaging for the spinal cord and nerves. Conditions in which MRI is used include: Optic neuritis Vestibular schwannoma Multiple sclerosis Pituitary adenoma Spinal cord tumor Neurofibroma Viral encephalitis Hippocampal volumetry CT scan  is preferred when the timing is critical. So, the investigation of choice for stroke is an  NCCT  This helps to rule out  hemorrhagic stroke. The investigation of choice for i schemic stroke  is a  diffusion-weighted MRI.

CT  is the initial investigation for  aortic dissection  as it is more widely available and takes a  shorter time  when compared to MRI. MRI, though highly accurate for acute aortic disease evaluation, is usually confined to cases of severe renal insufficiency or when the use of iodinated contrast medium is absolutely contraindicated. The image below depicts CT chest showing Type A aortic dissection from the aortic root. (A) Axial view and (B) sagittal view. The arrows indicate the intimal flap. The image below shows the classification systems used for aortic dissection.  

Pulmonary CT angiography  is the best investigation for  pulmonary embolism. V/Q scan  is done in  pregnant  women. Shown below is a CT angiography demonstrating multiple filling defects both at the bifurcation ( saddle pulmonary embolism ) and in the pulmonary arteries. CT angiography  is the investigation of choice in  aortic aneurysm. Clinical prediction for pulmonary embolism: Well's, Modified Well's and Pulmonary Embolism Rule out Criteria (PERC) Three-level score probability: Two-level score probability: Pulmonary embolism rule out criteria (PERC): This is a quick OPD/casualty tool to rule out pulmonary embolism in patients with low clinical probability. It comprises  eight clinical variables.  If the patient meets all eight criteria, there is no need for further investigations. The variables include 1. Age <50 years 2. Heart rate <100 bpm 3. Sp02 ≥95% 4. No unilateral leg swelling 5. No hemoptysis 6. No recent trauma or surgery 7...

Hounsfield unit (HU) depends on the linear  attenuation co-efficient. Attenuation is the reduction of the intensity of an X-ray beam as it traverses matter. HU is used to measure the X-ray attenuation values in CT scanning, thus quantifying the  radiodensity  of the tissue. The Hounsfield scale, named after  Sir Godfrey Hounsfield  invented CT in the year 1972 and was awarded Nobel Prize for Medicine in the year 1979.

Spiral CT  is based on the technology called a  slip ring. It is a device that distributes the power supply between the patient table (or couch) and the gantry, which contains the spinning X-ray tube. The slip ring makes the  simultaneous movement  of the  patient and X-ray tube rotation possible. The process of CT imaging is  faster , and the entire trunk can be taken in a single breath-hold. Thus, there is no respiratory misregistration. Also in spiral CT,  3D reconstruction  can be done. Spiral CT is the investigation of choice for renal stones. It is also used for staging of colon cancer and for visualization of pulmonary embolism. Radiation exposure: CT abdomen = 500 chest X-rays (highest) CT head= 100 to 150 chest X-rays Mammography = 20 to 25 chest X-rays.