pathophysiology final
hypocalcemia
Manifestations/clincal findings:Calcium less than 8.5. Neural and Muscle effects(increased excitability) Sensations, especially numbess,tingling, skeltal muscle cramps.abdominal muscle spsms nd cramps, hyperactive reflexes, carpopedal spasm,tetany,laryngeal spasm. Cardio effects:hypotension,signs of cardiac insufficiency, decreased response to drugs that act by calcium-mediated mechanisms,prolongation of the QT interval predisposes to ventricular arrhythmias.Skeltal effects (Chronic deficiency):osteomalacia,bone pain.
renin-angiotensin-aldosterone
renin-angiotensin system, the regulation of sodium balance, fluid volume, and blood pressure. In response to reduced perfusion, renin is secreted, which hydrolyzes a plasma globulin to release angiotensin I, which is rapidly hydrolyzed to angiotensin II, a powerful vasoconstrictor; angiotension II also stimulates aldosterone secretion, which causes sodium retention, an increase in blood pressure, and restoration of renal perfusion, which shuts off the signal for renin release (negative feedback). Angiotensin-converting enzyme also deactivates bradykinin, a vasodilator. Also called renin-angiotensin-aldosterone system. Mosby's Medical Dictionary, 8th edition. © 2009, Elsevier.
hyponatremia
Causes By Mayo Clinic staff Sodium plays a key role in your body. It helps maintain normal blood pressure, supports the work of your nerves and muscles, and regulates your body's fluid balance. When the sodium levels in your blood become too low, excess water enters your cells and causes them to swell. Swelling in your brain is especially dangerous because the brain is confined by your skull and unable to expand. Types of hyponatremia Normal blood plasma contains between 136 and 145 milliequivalents per liter (mEq/L) of sodium. Hyponatremia occurs when the sodium in your blood falls below 135 mEq/L. The imbalance between sodium and water in your blood may occur in three primary ways: ■In hypervolemic hyponatremia, excess water dilutes the sodium concentration, causing low sodium levels. Hypervolemic hyponatremia is commonly the result of kidney failure, heart failure or liver failure. ■In euvolemic hyponatremia, normal water levels are combined with low sodium levels. This condition is commonly due to chronic health conditions, cancer or certain medications. ■In hypovolemic hyponatremia, your water and sodium levels are both low. This may occur, for example, when exercising in the heat without replenishing your fluid electrolytes or with marked blood loss. Causes of hyponatremia Many possible conditions and lifestyle factors can lead to hyponatremia, including: ■Consuming excessive water during exercise (exertional hyponatremia). Because you lose sodium through sweat, drinking too much water during endurance activities, such as marathons and triathlons, can dilute the sodium content of your blood. ■Hormonal changes due to adrenal gland insufficiency (Addison's disease). Your adrenal glands produce hormones that help maintain your body's balance of sodium, potassium and water. ■Hormonal changes due to an underactive thyroid (hypothyroidism). Hypothyroidism may result in a low blood-sodium level. ■Water pills (diuretics) — especially thiazide diuretics. Diuretics work by making your body excrete more sodium in urine. ■Syndrome of inappropriate anti-diuretic hormone (SIADH). In this condition, high levels of the anti-diuretic hormone (ADH) are produced, causing your body to retain water instead of excreting it in your urine. ■Primary polydipsia. In this condition, your thirst increases significantly, causing you to drink excessive amounts of fluid. ■Certain medications. Some medications, such as some antidepressants and pain medications, can cause you to urinate or perspire more than normal. ■The recreational drug Ecstasy. This amphetamine causes a ripple effect on the body's ADH and water levels that — especially when combined with heavy drinking — increases the risk of severe and even fatal cases of hyponatremia. ■Chronic, severe vomiting or diarrhea. This causes your body to lose fluids and electrolytes, such as sodium. ■Dehydration. In dehydration, your body loses fluids and electrolytes. ■Diet. A low-sodium, high-water diet can disturb the proper balance between sodium and fluids in your blood. Excessive intake of diuretics, including beer, can have the same effect. ■Cirrhosis. Liver disease can cause fluids to accumulate in your body. ■Kidney problems. Kidney failure and other kidney disease may render your body unable to efficiently remove excess fluids from your body. ■Congestive heart failure. This condition causes your abdomen and lower extremities to retain fluids. Risk factors Symptoms
hypocalcemia
Causes:It manifests as a symptom of a parathyroid hormone [PTH] deficiency/malfunction, a Vitamin D deficiency, or unusually high magnesium levels hypermagnesemia, or low magnesium levels hypomagnesemia. More specifically, hypocalcemia may be associated with low PTH levels as seen in hereditary hypoparathyroidism, acquired hypoparathyroidism (surgical removal MCC of hypoparathyroidism), and hypomagnesemia. Hypocalcemia may be associated with high PTH levels when the parathyroid hormone is ineffective; in chronic renal failure, the hydroxylation of vitamin D is ineffective, calcium levels in the blood fall, and high PTH levels are produced in response to the low calcium, but fail to return calcium levels to normal. Eating disorders Excessive dietary magnesium, as with supplementation.
hypokalemia
Definition-serum potassium levels below 3.5. Because of transcellular shifts, temporary changes in serum potassium may occur as the result of movement b/t the ICF and ECF compartments. A potasium intake of at least 10 to 30 mEq/day is needed to compensate obligatory urine losses.A person on a potassium free diet continues to lose approximately 5 to 15 mEq of potassium daily.Causes:deficit can be grouped into three categories:inadequate intake,excessive loss through the kidney,skin and GI tract,redistribution b/t the ICF and ECF compartments.
hypokalemia
Manifestations- potassium less than 3.5, Thirst and Urine- Increased thirst,Inability to concentrate urine with polyuria and urine with low specific gravity,Effects of changes in membrane potentials on neural and muscle function-GI:anorexia,n/v,abdominal distention,paralytic ileus(severe hypokalemia).Neuromuscular:muscle weakness,flabbiness,fatigue,muscle cramps and tenderness,paresthesias(sensations),paralysis (severe hypokalemia).CNS:confusion, depression.Cardio:postural hypotension,predisposition to digitalis toxicity,electrocardiogram changes,cardiac arrhythmias,Acid base balance:metabolic acidosis.
hypercalcemia
Manifestations/clinical findings:calcium less than 10.5. Inability to concentrate urine and exposure of kidney to increased concentration of calcium:polyuria,increased thirst, flank pain, signs of acute renal insufficiently, signs of kidney stones. neural and muscle effects(Decreased Excitiabity) muscle weakness,ataxia,loss of muscle tone.lethargy,personality and behavioral changes,stupor and coma. Cardio:HTN,shortening of QT interval,atrioventricular block.GI effects:anorexia,n/v,constipation.
hyponatremia
Symptoms By Mayo Clinic staff Hyponatremia signs and symptoms may include: ■Nausea and vomiting ■Headache ■Confusion ■Lethargy ■Fatigue ■Appetite loss ■Restlessness and irritability ■Muscle weakness, spasms or cramps ■Seizures ■Decreased consciousness or coma
hyercalcemia
Treatment:Treatments and drugs If you have severe hypercalcemia, you may need to be hospitalized to reduce calcium to a safe level and protect your kidneys and bones. If so, hypercalcemia treatment may include: ■Intravenous fluids to rehydrate you ■Loop diuretic medications (such as furosemide) to help flush excess calcium from your system and keep your kidneys functioning ■Intravenous bisphosphonates, a group of drugs that includes pamidronate (Aredia) and zolendronate (Zometa), to inhibit bone breakdown ■Calcitonin, a hormone produced by your thyroid gland, to reduce bone reabsorption and slow bone loss ■Glucocorticoids (corticosteroids), to help counter the effects of too much vitamin D in your blood caused by hypercalcemia ■Hemodialysis to remove excess waste and calcium from your blood if your kidneys are impaired and you don't respond to other treatments Once your blood calcium returns to a safe level, treatment for hypercalcemia depends on the underlying cause. Primary hyperparathyroidism If your hypercalcemia is mild, you and your doctor may choose to watch and wait, monitoring your bones and kidneys over time to be sure they remain healthy. If you've already lost bone mass or developed kidney stones, your doctor may recommend surgery to remove the affected parathyroid gland or glands (parathyroidectomy), which cures the condition in most cases. If you're not a good candidate for surgery, your doctor may recommend medication. ■Surgery. Traditionally, surgery has involved a noticeable incision, exploration on both sides of the neck and general anesthesia. But a newer technique, known as minimally invasive radioguided parathyroidectomy, may offer an easier option for some people. In this procedure, doctors use a radioisotope scan (sestamibi scan) to help locate the abnormal parathyroid gland before surgery. For the scan, you're given a small dose of a radioactive material that's absorbed only by the overactive parathyroid gland — not by healthy ones. During the operation, the surgeon uses the sestamibi scan results as a map to locate the abnormal gland. In some cases, a probe that detects radioactivity is used to confirm the location. All surgery poses some risks. A small number of people undergoing parathyroid surgery experience damage to the nerves controlling their vocal cords, and some develop chronically low calcium levels, requiring treatment with calcium and vitamin D. In addition, although it's usually very effective, parathyroid surgery won't cure the problem in every case. ■Medication. The drug cinacalcet (Sensipar), which has been shown to lower calcium levels in the blood by reducing production of parathyroid hormone, may be effective for some people with hyperparathyroidism. If you've developed osteoporosis, taking medications called bisphosphonates, alendronate (Fosamax), risedronate (Actonel) or ibandronate (Boniva), can preserve bone mass in your spine and hip, reducing your risk of fractures. Cancer The decision of whether and how to treat hypercalcemia caused by cancer depends on the overall cancer treatment goals you've established with your doctor. Relieving the signs and symptoms of hypercalcemia may involve intravenous fluids for dehydration and medication such as bisphosphonates or other drugs to stop the breakdown of bone. Treatment of hypercalcemia may reduce pain, improve quality of life, and enable you to remain active and undergo cancer treatments.
body water balance
intracellular /extracellular.
hyperkalemia
Treatment-treament of potassium excess varies with the severity of the disturbance and focuses on decreasing or curtailing intake or absorption, increasing renal excretion increasing cellular uptake. Decreased intake can be achieved by restricting dietary sources of potassium. The major ingredient in most salt substitutes is potassium chloride, and such substitutes should not be given to patients with renal problems. Increasing potassium output often is more difficult. People with renal failure may require hemodialysis or peritoneal dialysis to reduce serum potassium levels. Most emergency methods focus on measures that cause serum potassium to move from ECF into ICF compartment. An intravenous infusion of insulin and glucose is often used for this purpose.
hyponatremia
Treatments and drugs By Mayo Clinic staff Hyponatremia treatment is aimed at addressing the underlying cause, if possible. If you have moderate, chronic hyponatremia due to your diet, diuretics or excessive water consumption, your doctor may recommend temporarily cutting back on fluids. He or she also may suggest adjusting your diuretic use to increase the level of sodium in your blood. If you have severe, acute hyponatremia, you'll need more aggressive treatment. Options include: ■Intravenous fluids. Your doctor may recommend intravenous (IV) administration of a sodium solution to raise the sodium levels in your blood. This often requires a stay in the hospital. ■Medications. You may take medications to manage the signs and symptoms of hyponatremia, such as headache, nausea and seizures. ■Hormone therapy. If adrenal insufficiency (Addison's disease) is the cause of hyponatremia, you may take hormones to replace the deficiency.
hypercalcemia
Causes-Causes Parathyroid glands Your body stores calcium mainly in your bones, but calcium also resides in certain cells, particularly in your muscles, and in your blood. You consume calcium in foods such as milk, cheese and leafy green vegetables, and usually your body rids itself of any excess in your urine, keeping a normal level of calcium in your blood. Two key regulators Two hormones serve as primary regulators of the calcium in your blood: parathyroid hormone and calcitonin. When the calcium in your blood falls, your body produces more parathyroid hormone; when your calcium blood level rises, your body produces less of the hormone. In a finely tuned system of checks and balances, parathyroid hormone stimulates your bones to release calcium into your blood, your digestive tract to absorb more calcium, and your kidneys to excrete less calcium and activate more vitamin D, which plays a vital role in calcium absorption. Normally, if the calcium level in your blood rises too high, your thyroid gland produces calcitonin, a hormone that slows the release of calcium from your bones. The balance is thrown off in hypercalcemia, and your body can't counter the effects of too much calcium as it usually does. Causes of hypercalcemia include: ■Overactivity of parathyroid glands. The primary cause of hypercalcemia is overactivity in one or more of your four parathyroid glands (primary hyperparathyroidism). ■Cancer. Certain types of cancer, particularly lung cancer and breast cancer, as well as some cancers of the blood, such as multiple myeloma, increase your risk of hypercalcemia. Some cancerous (malignant) tumors produce a protein that acts like parathyroid hormone, stimulating the release of calcium from your bones into your blood. This is considered a paraneoplastic syndrome, your body's response to the presence of cancer or a substance the cancer produces. Spread of cancer (metastasis) to your bones also increases your risk of hypercalcemia. ■Other diseases. Some diseases that produce areas of inflammation due to tissue injury (granulomas) may raise blood levels of vitamin D (calcitriol). Granulomatous diseases include tuberculosis, an infectious lung disease, and sarcoidosis, an inflammatory disease that usually begins in your lungs. Elevated levels of calcitriol stimulate your digestive tract to absorb more calcium, which raises the level of calcium in your blood. Also, a rare genetic disorder known as familial hypocalciuric hypercalcemia causes an increase of calcium in your blood because of faulty calcium receptors in your body. ■Disease effects. People with cancer or other diseases that cause them to spend a great deal of time sitting or lying down may develop hypercalcemia because over time, bones that don't bear weight release calcium into the blood. ■Medications. Certain drugs, such as lithium, which is used to treat bipolar disorder, may increase the release of parathyroid hormone and cause hypercalcemia. Thiazide diuretics can cause elevated calcium levels in your blood by decreasing the amount of calcium lost in your urine. ■Supplements. Excessive intake of calcium or vitamin D supplements over time can raise calcium levels in your blood above normal. ■Dehydration. A common cause of mild or transient hypercalcemia is dehydration, because when there is less fluid in your blood, calcium concentrations rise. Hyperparathyroidism and cancer are responsible for more than 90 percent of sustained hypercalcemia. Complications Symptoms
hyperkalemia
Clinical findings-s/s of potassium excess are closely r/t the alterations in neuromuscular excitability. The neuromuscular manifestations of potassium excess usually are absent until the serum concentration exceeds 6. The first symptom associated with hyperkalemia typically is paresthesia(any sensation-numbness,tingling,pins and needlesfeeling). there may be complaints of generalized muscle weakness/ dyspnea secondary to respiratory muscle weakness. the most serious effect of hyperkalemia is on the heart. As potassium levels increase, disturbances in cardiac conduction occur. The earliest changes are peaked,narrow T waves and widening ofthe QRS complex. if serum levels contnue to rise, the PR inteerval becomes prolonged and is followed by disappearance of P waves. The heart rate maay be slow. Ventricular fibrillation and cardiac arrest are terminl events. Detrimental effect of hyperkalemia on the heart are most pronounced when the serum potasium level rises rapidly.
hyperkalemia
Definition of Hyperkalemia Hyperkalemia: Elevated blood potassium. Potassium is the major positive ion (cation) found inside of cells. The chemical notation for potassium is K+. The proper level of potassium is essential for normal cell function. An abnormal increase (or decrease) of potassium can profoundly affect the nervous system and heart, and when extreme, can be fatal. The normal blood potassium level is 3.5 - 5.0 milliEquivalents/liter (mEq/L), or in international units, 3.5 - 5.0 millimoles/liter (mmol/L). See also: Potassium balance.
hypocalcemia
Definition-Hypocalcemia is an electrolyte imbalance and is indicated by a low level of calcium in the blood. The normal adult value for calcium is 4.5-5.5 mEq/L. Calcium is important for healthy bones and teeth, as well as for normal muscle and nerve function. Normal blood calcium levels are maintained through the actions of parathyroid hormone (PTH), your kidneys and intestines. If your blood test results show hypocalcemia, your doctor may check your albumin level as well. If your albumin is low, your calcium level should be corrected for this. A corrected calcium level will be higher if the albumin is low.
hypercalcemia
Definition:serum concentration greater than 10.5. Falsely elevated levels of calcium can result ffrom prolonged drawing of blood with an excessively tight tourniquet. Increased plasma proteins(hyperalbuminemia, hyperglobulinemia) may elevate the total serum calcium but not effect the ionized calcium concentration.
hyponatremia
Hyponatremia is a condition in which your blood level of sodium is abnormally low. Sodium, an electrolyte, helps regulate water levels in the fluid in and around your cells. In hyponatremia, one or more factors — ranging from an underlying medical condition to excessive water intake during endurance sports — cause sodium levels to drop. When this happens, your body's water levels rise, and your cells begin to swell. This swelling can cause many health problems, from mild to severe. Hyponatremia treatment is aimed at resolving the underlying condition. Depending on the cause of hyponatremia, you may simply need to cut back on fluids. In other cases of hyponatremia, you may need intravenous fluids and medications.
renin-angiotensin-aldosterone mechanism
The RAA mechanism plays an important role in the short and long term regulation of blood pressure. Renin is synthesized and stored in the juxtaglomerular cells of the kidney. This enzyme is released in response to a decrease in renal blood flow or a change in the compositionn of the distal tubular fluid, or as a result of sympatthetic nervous system stimulation. Most of the renin that is released leaves the kidney and enters the blood stream, where it acts enzymatically to convert an inactive circulating plasma protein called angiotensinogen to angiotensin I. Angiotensin I, in turn, travels to the small blood vessels of the lung, where it is converted to angiotensin II by the angiotensin-converting enzyme that is present in the endothelium of the lung vessels. Angiotensin II is a potent vasoconstrictor, and it acts directly on the kidneys to decrease salt and water excretion.
hyperkalemia
causes-The major causes of hyperkalemia are kidney dysfunction,Chronis causes are almost always associatedrenal failure. Usually the GFR must decline to less than 10 befor hyperkalemia develops.Some renal disorders such as sickle cell nephropathy, lead nephropathy, and systemic lupus nephritis, can selectively impair tubular secretion of potassium without causing renal failure. Others, diseases of the adrenal gland, potassium sifting out of cells into the blood circulation, and medications. Kidney dysfunction Potassium is normally excreted by the kidneys, so disorders that decrease the function of the kidneys can result in hyperkalemia. These include: •acute and chronic renal failure, •glomerulonephritis, •lupus nephritis, •transplant rejection, and •obstructive diseases of the urinary tract, such as urolithiasis (stones in the urinary tract). Furthermore, patients with kidney dysfunctions are especially sensitive to medications that can increase blood potassium levels. For example, patients with kidney dysfunctions can develop worsening hyperkalemia when given salt substitutes that contain potassium, when given potassium supplements (either orally or intravenously), or medications that can increase blood potassium levels. Examples of medications that can increase blood potassium levels include: •ACE inhibitors, •nonsteroidal anti-inflammatory drugs (NSAIDs), •Angiotensin II Receptor Blockers (ARBs), and •potassium-sparing diuretics (see below).
