Mark Nelligan Flashcards
What are the normal measurements of JVP
no more than 3cm
what is JVP?
Jugular venous pressure (JVP) provides an indirect measure of central venous pressure. This is possible because the internal jugular vein (IJV) connects to the right atrium without any intervening valves, resulting in a continuous column of blood.
5 causes of raised JVP
- Right sided heart failure (commonly caused by L sided heart failure)
- Pulmonary hypertension
- COPD
- Interstitial lung disease
- Tricuspid regurgitation
- Constrictive pericarditis- chronic pericarditis/ inflammation of pericardium causing scarring, thickening and muscle tightening.
describe kidney filtration in the glomerulus
- Endothelium
- this has relatively large pores (70-100 nanometers in diameter), which solutes, plasma proteins and fluid can pass through, but not blood cells.
• Basement membrane
prevent plasma proteins from being filtered out of the bloodstream.
- Epithelium
- this layer consists of specialized cells called podocytes. These cells are attached to the basement membrane by foot processes (pedicels). They wrap around the capillaries, but leave slits between them, known as filtration slits. A thin diaphragm between the slits acts as a final filtration barrier before the fluid enters the glomerular space
describe kidney filtration in the convoluted tubule
Gs Early proximal convoluted tubule
• Sodium/potassium ATPase, 3 Na+ out, 2K+ in
• Sodium/H+ exchanger, which enables reabsorption of bicarbonate.
• Glucose, amino acids and other substances diffuse out of the epithelial cell down their concentration gradients on passive transporters and are then reabsorbed by the blood capillaries.
• By the time the filtrate has reached the mid part of the proximal tubule, 100% of the filtered glucose and amino acids have been reabsorbed, and large amounts of sodium, bicarbonate, phosphate, lactate, and citrate ions.
Late proximal convoluted tubule
• Chloride/formate anion exchangers driven by the high concentration of chloride in the filtrate. Chloride diffuses out of the cell through channels in the cell wall, and then on into the bloodstream.
• Small solutes e.g. water and sodium chloride are reabsorbed via junctions in the epithelial cells of the tubule wall.
what is reabsorbed in the descending LoH
aquaporins allow water to pass from the filtrate into the interstitial fluid
describe kidney filtration in the thick ascending limb
• Na/K/Cl transporter and Na/K ATPase 1Na+, 2Cl- and 1K+ in to ascending limb from the lumen via three-ion cotransporter, then Na+ out into blood and K+ in to ascending limb via Na/K pump, Cl- and K+ out down electrochemical gradient
impermeable to water
describe kidney filtration in the distal tubule
selectively secretes and absorbs ions to maintain electrolyte balance and pH
describe kidney filtration in the collecting duct
reabsorbs solutes and water from the filtrate
How is GFR calculated
Abbreviated MDRD for eGFR equation: 186 x (Creatinine/88.4)-1.154 x (Age)-0.203 x (0.742 if female) x (1.210 if black)
5 causes of left axis deviation
- Normal variant
- Mechanical shift- ascites, high diaphragm
- Left atrial hypertrophy
- Left bundle branch block
- Wolff-Parkinson-White Syndrome
- COPD
- HyperK
- Right ventricular ectopic rhythms
MICA for calcium carbonate
- MOA: basic inorganic salt that neutralises HCl. Inhibits pepsin by increasing the pH via adsorption. 90% is converted to insoluble calcium salts.
- Indications: heartburn and acid indigestion, nutritional supplement or hypoCa tx, hypophosphataemia
- Contraindications: hypercalcaemia of malignant disease or conditions associated with hypercalciuria
- Adverse effects: constipation, diarrhoea, hypercalcaemia, nausea, hypercalciuria, flatulence, GI discomfort, skin reactions.
- Class of drug: antacid/ calcium
- Metabolism & elimination: not metabolised, excreted in the faeces. Majority is reabsorbed in the ascending limb of the LoH and DCT. Secreted by sweat glands.
MICA for calcium gluconate
- MOA: calcium salt that directly replenishes serum calcium levels.
- Indications: severe acute hypocalcaemia or hypocalcaemic tetany, acute severe hyperK, mild asymptomatic hypocalcaemia
- Contraindications: conditions associated with hypercalcaemia e.g. malignancy, conditions associated with hypercalciuria e.g. malignancy. Cautions: hx of nephrolithiasis, sarcoidosis
- Adverse effects: arrhythmias, circulatory collapse, feeling hot, hyperhidrosis, hypoT, vasodilation, vomiting, GI disorder
- Class of drug: calcium
- Metabolism & elimination: doesn’t need metabolization by the liver. Excretion- 20% renal via urine, 80% faecal.
DRDEACPIMP for chronic kidney disease
• Definition: kidney damage for >3months based on findings of abnormal structure or function or GFR <60ml/min/1.73m2 for >3months with/out evidence of kidney damage.
Risk factors: HT, DM, smoking, obesity, CVD, FHx, hypercholesterolaemia, polycystic kidney disease, long term steroid use and lithium use, age >60, recurrent UTIs, black, Asian and minority ethnic groups are 5 times more likely to develop CKD.
- Ddx: AKI, chronic glomerulonephritis, diabetic nephropathy, multiple myeloma, nephrolithiasis, nephrosclerosis
- Epidemiology: ~3 million people in the UK have CKD, 63000 people are being treated for renal failure, ~1000 children with CKD in the UK, 10% in women, 6% in men.
- Aetiology: two main causes are DM (24%) and HT (11%)
- Clinical features: fatigue, weakness, anorexia, vomiting, metallic taste, pruritus, restless legs, bone pain, impotence, dyspnoea, oedema, pallor, jaundice, brown nails, purpura, pleural effusion.
- Pathophysiology: progressive deterioration of renal function leading to problems with electrolyte and fluid balance and consequent symptoms- anaemia is caused by deficient EPO production.
- Ix: Bloods- normocytic normochromic anaemia, ESR, U&E (high urea and creatinine), glucose, Ca (low), phosphate (raised), PTH (raised), urine MS&C dipstick, 24h urine proteins, renal US, CXR- cardiomegaly, pleural/pericardial effusions or pulm oedema, bone x-rays may show osteodystrophy, renal biopsy considered if cause unclear with normal sized kidneys.
- Mx: refer to nephrologist, treat reversible causes e.g. relieve obstruction, stop nephrotoxic drugs, lifestyle changes- exercise, weight loss, fluid intake, Na restriction, moderate diet, prepare for dialysis/transplantation
- Prognosis: 1 in 50 people will develop kidney failure
MICA for DDAVP (desmopressin)
- MOA: binds to V2 receptors in basolateral membrane of cells of DCT and CD stimulating adenylyl cyclase, leading to an increase in aquaporins. Mimics ADH.
- Indications: many indications including diabetes insipidus tx, primary nocturnal enuresis (inability to control urination), post-op polyuria or polydipsia, renal function testing
- Contraindications: cardiac insufficiency, diuretics, hx of hypoNa, polydipsia in alcohol dependence, psychogenic polydipsia, siADH, von Willebrand’s disease type IIb
- Adverse effects: hyponatraemia, abdo pain, aggression in children, allergic dermatitis, emotional disorder, fluid retention, headache, hyponatraemic seizure, vomiting, increased weight.
- Class of drug: vasopressin and analogues
- Metabolism & elimination: no metabolism by the liver, excreted in the urine