Medicine Hack

Definition: It is an abnormal communication between an artery and a vein (or veins). It may be 1) a congenital malformation, 2) acquired by the trauma of a penetrating wound, 3) iatrogenic in which AVFs are created surgically in the arms or legs of patients undergoing renal dialysis. All arteriovenous communications have a structural and a physiological effect. Structural effect: The veins become dilated, tortuous and thick walled (arterialised). Physiological effect: There is high-pressure from the arterial system and an enhanced venous return/venous pressure. This results in an increase in pulse rate and cardiac output. The pulse pressure is high if there is a large and persistent shunt. Left ventricular enlargement and later cardiac failure may occur. A congenital fistula in the young may cause overgrowth of a limb. In the leg, indolent ulcers may result from relative ischaemia below the short circuit. Clinical features: Clinically, a pulsatile swelling or dilated to...

Epidemiology:   Incidence of 3/1000 births.  4 times more in males.  Aetiology is unknown. In some cases there seems to be a familial association. In such families the mother has suffered from the condition in 50 per cent of cases. Characteristically it is a first-born male child that is most commonly affected. The condition is most commonly seen at 4 weeks after birth ranging from the third week to, on rare occasions, the seventh. Inexplicably, it is the time following birth that seems important and not the child’s gestational age. A premature infant will also develop the condition at about 4 weeks after birth. Pathology: Grossly hypertrophied musculature of the pylorus and adjacent antrum, the hypertrophy being maximum in the pylorus itself. The mucosa is compressed such that only a probe can be inserted. Clinical features : Vomiting is the presenting symptom that after 2—3 days becomes forcible and projectile. The child vomits milk and no bile is p...

Pathology: In some cases, the scarring process remains in the remodelling phase for longer than usual. These hypertrophic scars are more cellular and more vascular than mature scars.  There is increased collagen production and collagen breakdown but the balance is such that excess collagen is produced.  Clinical features: The hypertrophic scars are red, raised, itchy and tender. They will eventually mature to become pale and flat, and it is this spontaneous resolution which distinguishes hypertrophic scars from keloid scars.  Cause: Hypertrophic scars typically occur in wounds where healing was delayed, e.g. in cases where infection or dehiscence has occurred.  Incidence: They are more common in children and where skin tension is high such as the tip of the shoulder or any scar that runs across relaxed skin tension lines. Prevention and treatment: The risk of developing a hypertrophic scar can be minimised by ensuring quiet primary healing...

Definition: Barrett’s esophagus is characterized by an intestinal metaplastic change in the lining mucosa of the esophagus in response to chronic gastro­esophageal reflux.  The condition is named after Norman Barrett, an Australian surgeon who drew attention to the columnar-lined esophagus in 1950. It is still not well understood why some people develop esophagitis and others develop Barrett’s esophagus often without significant esophagitis.  Pathology: In Barrett’s esophagus the junction between squamous esophageal mucosa and gastric mucosa moves proximally. The columnar epithelium is more acid resistant than the squamous epithelium. So this metaplasia appears to be a protective adaptation. The patient of chronic reflux esophagitis will find his symptoms decrease when he has developed Barrett's esophagus. Incidence: It is mainly seen in white man and the prevalence increases with age.  Several types of gastric-type mucosa may be found in the lower esophagus....

It refers to the superficial peri-umbilical bruising of the subcutaneous fat. It can be seen in the following cases: 1) acute pancreatitis (classically), 2) bleeding from blunt abdominal trauma, rupture of abdominal aorta and ruptured ectopic pregnancy. The sign was actually first described by Thomas Cullen in 1916 in a case of ruptured ectopic pregnancy.

Definition: It is defined as the introduction of a fluid drug under pressure using a syringe equipped with a hollow needle into the loose connective tissue below the dermis i.e. into the hypodermis. It has a low absorption there because of the low vascularisation but since it contains pain receptors, injection can be painful depending on the volume administered. For structure of skin, consider this page :  Skin structure Sites: 1) outer sides of arm, 2) front of upper outer thigh, 3) above and below the spine of scapula, 4) abdomen extending from the costal margin to the iliac crest except 5 cm all around the umbilicus. Angle of insertion of needle: 1) 90 degrees with a short needle, 2) 45 degrees with a longer needle. Techniques: 1) Pinch skin slightly to make 3 cm fold, 2) Insert needle quickly and firmly, 3) Release skin, 4) Aspirate and make sure that needle is not in a vessel, 5) Remove needle by gentle pressure with antiseptic swab, 6) Mass...

The double-ring test is clearly shown in this photo. It is also known as the ring sign or halo sign. The patient was brought following an injury to the head and was bleeding moderately from the nose but the blood was more watery than normal. CSF rhinorrhea was suspected. The dextrose stick test was positive to the sample and when placed on a filter paper, we got an inner ring of blood and a halo, followed by an outer ring of CSF. Though this has been a classical medical test, it is not 100% reliable.

Battle sign refers to the post auricular ecchymosis that occurs following trauma to the middle cranial fossa of the skull. It may indicate underlying brain trauma. The picture above shows one patient who came to the emergencies few hours after the head injury while in the one below it, patient was brought in a confused state few days after trauma to his head. The sign was named after William Henry Battle, who was a English professor of surgery and pathology.

1. For adults requiring a peripheral catheter, upper extremity site is preferred. If it is for a child, then we can use both upper or lower extremities as well as scalp sites. 2. The catheter site should be evaluated everyday and if there is any sign of phlebitis, the catheter should be removed immediately. 3. For central catheters in adults, it is better to use the jugular or subclavian route rather than the femoral one. 4. Systemic antimicrobial prophylaxis is not essential when using I.V catheters.

The 6 P's are: 1) Pain, 2) Pallor, 3) Pulselessness, 4) Paralysis, 5) Paraesthesia, 6) Perishingly cold.

1) There is usually a tingling sensation in the throat in hemoptysis while in hematemesis the patient will usually complain from nausea and upset stomach. 2) The blood is usually frothy and bright red in hemoptysis while it is dark red in hematemesis, non-frothy and food particles may also be present at the same time. 3) Blood in hematemesis will give an acidic pH when tested with litmus paper whereas that in hemoptysis will be neutral to alkaline. 4) Stools will be almost always positive for occult blood in hematemesis while it is usually negative in case of hemoptysis. But it can also be positive at times if the patient has swallowed his sputum. Last reviewed on: 1 September 2015

Peptic ulcers are created by an imbalance between the gastroduodenal mucosal defenses and the damaging forces that overcome such defenses. It is very well depicted above. H.pylori does not invade the tissues but it causes intense local inflammation. It has flagella that allows it to move in the viscous mucous. Bacterial proteases and phospholipases break down the glycoprotein-lipid complexes in the gastric mucous, thus weakening the first line of mucosal defense. It also produces urease that breaks down endogenous urea to form ammonia. This causes the pH to increase locally. The H.pylori also has adhesins that make it bind to the cells and finally they elaborate toxins that cause further damage like metaplasia. NSAIDs and aspirin are inhibitors of cyclooxygenase (COX). Thus they prevent the synthesis of prostaglandins. The latter is responsible for the promotion of mucin synthesis and vasodilation. In the absence of prostaglandins, the mucinous layer is depleted and the decreas...

 DEFINITION  Hypokalemia is defined as a serum potassium level of less than 3.5 mmol/L. Normal level= 3.5-5.5 mmol/L. It is encountered in >20% of patients. Patients are usually asymptomatic but severe arrhythmias and rhabdomyolysis can occur. Non-specific complaints include easy fatiguability and skeletal muscle weakness. The preferred method of replacement is via the oral route but at times this is not possible. The article below will give you an idea about how to calculate the amount of KCl to be given I.V. 1) Potassium deficit in mmol is calculated as given below: K deficit  (mmol) = (K normal lower limit  - K measured ) x kg body weight x 0.4 2) Daily potassium requirement is around 1 mmol/Kg body weight. 3) 13.4 mmol of potassium found in 1 g KCl . ( molecular weight KCl = 39.1 + 35.5 = 74.6) Suppose we get an asymptomatic patient of  70 Kg with a serum potassium level of 3.0 mmol/L and he is on nil by mouth but having...

The Richter hernia occurs when only the antimesenteric border of the bowel herniates through the fascial defect. The Richter hernia involves only a portion of the circumference of the bowel. As such, the bowel may not be obstructed, even if the hernia is incarcerated or strangulated, and the patient may not present with vomiting. The Richter hernia can occur with any of the various abdominal hernias and is particularly dangerous, as a portion of strangulated bowel may be reduced unknowingly into the abdominal cavity, leading to perforation and peritonitis.

Doing annual mammograms from age 40-84 can greatly save lives. If annual mammograms are done as from the age of 40, the risk of dying from breast cancer decreases by nearly 71%. 

Fever that occurs on starting a drug without any other probable cause of fever is known as antibiotic fever. It may be part of an allergic reaction to the drug or a preservative of the drug. It usually occurs with beta lactam antibiotics, procainamide, alpha methyl dopa and isoniazid.

This is also a case of perforated duodenal ulcer in a 34 yr old lady. Note the rim of gas above the fundal gas.

Massive  gas under diaphragm was seen in this case of perforated duodenal ulcer. Patient was a 28 yr old male with past history of chronic gastritis. He presented to A&E with acute abdomen. O/E rigidity of abdomen was positive and bowel sound was absent.