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The effects are similar with both raw and boiled onion extracts 300mg allopurinol for sale, indicating that the active components are probably stable cheap 300mg allopurinol mastercard. Preventing Nutritional and Oxidative Stress Diabetes is characterized by increased nutritional and oxidative stress cheap allopurinol 300mg fast delivery. Individuals with diabetes typically have elevated levels of free radicals and oxidative compounds. They also greatly increase the inflammatory process by increasing the formation of inflammatory mediators such as C-reactive protein. One of the critical goals in nutritionally supporting individuals with diabetes is to flood the body with a high level of antioxidant compounds to counteract the negative effects of free radicals and pro- oxidants. The implementation of this goal is achieved by using the recommendations given earlier, along with taking a flavonoid-rich extract and alpha-lipoic acid. Recent research suggests that flavonoids may be useful in treating diabetes, as well as in preventing long-term complications. Flavonoids such as quercetin promote insulin secretion and are potent inhibitors of glycosylation and sorbitol accumulation, while flavonoid-rich extracts such as bilberry and hawthorn have been shown to be helpful in diabetic retinopathy and microvascular abnormalities. Very Ginkgo biloba extract (24% 120– important in improving blood flow to the extremities (useful for neuropathy and foot ginkgo flavonglycosides) 240 mg ulcers). Grape seed extract or pine bark 150– Systemic antioxidant; best choice for most people younger than 50, especially if extract (>95% procyanidolic 300 mg retinopathy, hypertension, easy bruising, and poor wound healing exist. Green tea extract (>80% total 150– Best choice in the early stage of type 1 diabetes or if there is a family history of polyphenols) 300 mg cancer. Other beneficial effects include increasing intracellular vitamin C levels, decreasing the leakiness and breakage of small blood vessels (preventing easy bruising), promoting wound healing, and providing immune system support. Good dietary sources of flavonoids include citrus fruits, berries, onions, parsley, legumes, green tea, and red wine. For individuals with diabetes who are already showing signs of long-term complications, it is extremely important to take a flavonoid-rich extract. Because certain flavonoids concentrate in specific tissues, it is possible to take flavonoids that target specific body tissues. For example, because the flavonoids of bilberry (Vaccinium myrtillus) have an affinity for the eye, including the retina, bilberry is probably the best choice for a diabetic already exhibiting signs of diabetic retinopathy. Identify which flavonoid or flavonoid-rich extract is most appropriate and take it according to the recommended dosage (see the table opposite). There is tremendous overlap among the mechanisms of action and benefits of flavonoid-rich extracts; the key point here is to take the one that is most specific to your needs. Alpha-lipoic acid is a vitamin-like substance that is often described as “nature’s perfect antioxidant. Unlike vitamin E, which is primarily fat soluble, and vitamin C, which is water soluble, alpha-lipoic acid can quench either water- or fat-soluble free radicals both inside the cell and outside in the intracellular spaces. Furthermore, alpha-lipoic acid extends the biochemical life of vitamin C and E, as well as other antioxidants such as glutathione, the most important intracellular antioxidant. Alpha-lipoic acid is an approved drug in Germany for the treatment of diabetic neuropathy and has been successfully used there for more than 30 years. The beneficial effects of alpha-lipoic acid in diabetic neuropathy have been confirmed in several double-blind studies at a dosage of 400 to 600 mg per day. Recommendations for Specific Chronic Complications Following are additional recommendations for dealing with specific complications of diabetes. The most important method for reducing the risk of all these complications is achieving optimal blood glucose control. Elevated Cholesterol Levels Key natural products to lower cholesterol levels in diabetes are soluble fiber, garlic, and niacin. These agents are discussed fully in the chapter “High Cholesterol and/or Triglycerides. Niacin has been shown to address all of these areas much more significantly than the statin or other lipid-lowering drugs. However, one reason that niacin may not be as popular as it should be is the side effect of skin flushing—like a prickly heat rash—that typically occurs 20 to 30 minutes after the niacin is taken and disappears after about the same amount of time. Other occasional side effects of niacin include gastric irritation, nausea, and liver damage. Fatty liver is now considered to be as damaging as the effects of alcohol dependence and hepatitis C, and can also lead to fibrosis and cirrhosis of liver tissue. With overweight diabetic patients, therefore, high-dose niacin is to be used only under a physician’s recommendation. To reduce the side effect of skin flushing, use intermediate- release niacin, which is identical in dissolution pattern to the prescription niacin product Niaspan. Taking an intermediate-release product just before going to bed is recommended, as most people sleep right through any flushing reaction if one should occur. This form of niacin has long been used in Europe to lower cholesterol levels and also to improve blood flow in intermittent claudication, a peripheral vascular disease that is quite common in diabetes. If regular niacin or inositol hexaniacinate is being used, a dose of 500 mg should be given at night, before bed, for 1 week. The dosage should be increased to 1,000 mg the next week and 1,500 mg the following week. The 1,500 mg dosage should be given for two months before checking the response; the dosage can be adjusted up or down depending on the response. Intermediate-release niacin products such Niaspan can be used at the full dosage of 1,000 to 2,000 mg at night from the beginning. Regardless of the form of niacin being used, periodic checking (minimum every three months) of cholesterol, A1C, and liver function is strongly indicated. Retinopathy and Cataracts Diabetic retinopathy has two forms: (1) simple retinopathy, with bursting of blood vessels, hemorrhages, and swelling; and (2) proliferative retinopathy, with newly formed vessels, scarring, more serious hemorrhage, and retinal detachment. The development of laser photocoagulation therapy is an important treatment for the more severe proliferative retinopathy but is not indicated in milder forms of retinopathy, because the risk of visual loss usually outweighs the benefits. Extremely important in the battle against retinopathy are flavonoid-rich extracts, especially bilberry, pine bark, or grape seed extract. Flavonoids increase intracellular vitamin C levels, decrease the leakiness and breakage of capillaries, prevent easy bruising, and exert potent antioxidant effects. These effects are of particular value in dealing with the microvascular abnormalities of diabetes. Because the flavonoids in bilberry, pine bark, and grape seed extract have an affinity for the blood vessels of the eye and improve circulation to the retina, they are particularly helpful in slowing the progression of diabetic retinopathy, as evidenced by positive results in more than a dozen clinical trials. Diabetes is associated with a substantial disturbance in essential fatty acid metabolism. Sixteen different variables were assessed, including conduction velocities, hot and cold thresholds, sensation, tendon reflexes, and muscle strength. After one year, all 16 of these improved, 13 of them to a statistically significant degree. Treatment was more effective in patients with relatively well-controlled diabetes than in those with poorly controlled disease. In studies of diabetics, benfotiamine decreased advanced glycosylated end-product formation, decreased sorbitol accumulation, and reduced oxidative cellular damage. In a small study of patients with type 1, treatment with 600 mg benfotiamine with 300 mg alpha-lipoic acid produced better results in reducing the effects of hyperglycemia than benfotiamine alone. It may take a few days for the cream to start working, and it will continue to work only with regular application. The scientific investigation of acupuncture in diabetes includes both experimental and clinical studies. For example, animal experiments have shown that acupuncture can act on the pancreas to enhance insulin synthesis, increase the number of receptors on target cells, and accelerate the utilization of glucose, resulting in lowering of blood glucose. In one clinical study, 77% of patients treated with acupuncture noted significant improvement in their symptoms, with 21% noting that their symptoms were completely eliminated. Nephropathy Particularly important for kidney protection in diabetics is dietary fiber. Dietary fiber (especially soluble fiber) is fermented in the colon to produce short-chain fatty acids.

Differentiation between sinus tachycardia and atrial tachycardia may be accomplished by measuring the P-P interval buy allopurinol 300 mg without prescription. This interval is perfectly equidistant in atrial tachycardia but may be irregular in sinus tachycardia due to vagal effects cheap 100mg allopurinol with amex. But it is Heart Rate: 480 likely that stress generic 300mg allopurinol amex, pain and other known Rhythm: Normal sinus rhythm causes of sinus tachycardia in dogs (eg, elec- Axis: -30° to -60° Measurements: P-wave = 0. Postmortem and more premature contractions of the findings included pale and enlarged kidneys (might explain proteinuria and atria, junctional area or ventricle in a row, hypoproteinemia). The pericardial sac contained a large amount of clear yellow fluid, which was also present in the peritoneal cavities. The endocardium, are called a pair, run and tachycardia respec- myocardium and epicardium were grossly normal. Bigeminy is a rhythm characterized hypoalbuminemia, ascites and pericardial effusion, was considered to be the by alternating normal beats and premature primary disease in this case. Right ventricular failure will develop before left ventricular failure because the weaker right ventricle is less able to compensate contractions, while in trigeminy two normal for the additional strain induced by pericardial effusion. In this condi- tion, the atrial and ventricular rhythms are independent of each other, whereby the atrial rate is lower than the junctional or idioventricular rate. Pericardial effusion is the cardiovascular disease entity most often the ventricular depolarizations. The ven- tricular complexes may have a normal con- figuration or may be idioventricular depend- ing on the site of ventricular impulse formation. Nonselective angiocardiography was Intraventricular conduction disturbances performed in this pigeon. Rapid sequence serial radiographs showed impaired such as left bundle branch block and right ventricular function (courtesy of J. With halothane and methoxyflurane, respi- ratory and cardiac arrest routinely occur at the same time, and recovery from an anes- thetic-induced cardiac arrest is rare. With isoflurane, respiratory arrest typically oc- curs several minutes before cardiac arrest. Birds with severe arrhythmias induced by an overdose of isoflurane may recover with ap- propriate intermittent partial pressure ven- tilation. In this patient hypoxia Congestive heart failure is a clinical syn- was caused by a local mycotic tracheitis causing an inspiratory stridor and drome that can be defined as the compen- severe dyspnea. The causes of conges- tive heart failure are numerous and include endo- General anesthesia is typically associated with a cardial, epicardial, myocardial and combined dis- time-related and progressive decrease in heart rate eases. The condition should be differentiated from and a corresponding decrease in blood pressure. A Methoxyflurane and halothane are both cardiac de- diagnosis may be especially difficult in constrictive pressants that sensitize the heart to catecholamines. Backward failure involves in- creased atrial and venous pressure due to a failing ventricle, while forward failure in- volves decreased renal blood flow resulting in sodium and fluid retention. In response to low blood volume, renin is released from the juxtaglomerular cells of the kidney. The process is cumulative, ultimately lead- ing to death from the local effects of fluid accumulation. Systemic edema with hepatomegaly and ascites will predomi- nate in isolated right ventricular disease, or when both ventricles are affected. Left ventricular disease will result in in- creased pulmonary venous and capillary pressure. P atrium, is another contributing factor to the mitrale indicative of left atrial enlargement. Causes for sinoatrial arrest in birds include excessive vagal pendent on the presence of atrial systole, stimulation, thiamine deficiency, vitamin E deficiency and poisoning with perhaps through the effect of atrial relaxa- organophosphorus compounds. The resulting valvular insufficiency arrest suggest a pathologic condition of the atrium such as atrial fibrosis or dilatation. Clinical Findings: This bird was presented with short periods (several seconds) of syncope for several hours, two to three times a month. The sinoa- response to an increased workload, and it has trial arrest was considered to be a possible explanation for the observed syncopal been postulated that this predisposes birds attacks. Echocardiography in- dicated biatrial enlargement, distended hepatic vessels and ascites. Color-flow dop- pler indicated a mitral regurgitation and right sided heart failure. Repeated echocardiography indicated a decrease in the size of the heart and liver. Congestive heart failure complicated by atrial fibrilla- tion due to mitral valve insufficiency has been reported in a Pukeko. The high incidence of cardio- vascular failure in meat-type poultry is prob- ably the result of genetic selection for rapid growth and high breast meat yield, with no attention to cardiovascular health and stress resistance. The practice of inbreeding certain species of companion birds for color or size variations could have a similar effect. Halothane described at high altitudes, but it also occurs sensitizes the heart to adrenalin-induced arrhythmias (courtesy of J. The relatively higher oxygen demand causes Clinical Findings a hypoxemia, which in turn induces a polycythemia. With polycythemia, the blood is more viscous and Heart enlargement with a thin left ventricular wall more difficult to pump through the lungs. The in- has been reported as a common occurrence in mynah 22 creased workload results in right ventricular dilata- birds. A de- crease of the heart rate can be seen due to improvement of the circula- tion and parasympathetic (vagal) stimulation. A moderate increase in dietary information is available with regard to digoxin ther- sodium for one week may cause congestive heart apy in birds. Digoxin pediatric drops, rather than Treatment digoxin tablets, should be used in birds to improve Once congestive heart failure has been diagnosed, the accuracy of dosing. The dosage adequate blood plasma levels in Quaker Conures must be adjusted for the individual bird, but 1-2 (Monk Parakeet). Vegetative Endocarditis Cardiac glycosides are indicated in congestive heart Endocarditis of the aortic and mitral valves may failure, especially when accompanied by atrial fibril- cause vascular insufficiency, lethargy and dyspnea. Ventricular tachycardia may be a contraindi- Valvular endocarditis is most common in birds with cation because digitalis may induce ventricular fibril- chronic infections (eg, salpingitis, hepatitis and bum- lation in these cases. The disease is asso- ciated with bacteremia, and thromboem- bolisms may occur throughout the vascula- ture. The initial damage to the heart valves that induces vegetative endocarditis is usually unknown. Factors that have been associated with endocardial or valvular lesions include chronic bacterial septicemia, frostbite, con- genital lesions (that alter blood flow) and degenerative myocarditis. Entero- Electrocardiographic Diagnosis: P pulmonale and P mitrale are indicative of biatrial enlargement. The dyspnea had become progressively more severe for the few days before evaluation. Total protein and protein Erysipelothrix rhusiopathiae was recovered electrophoresis were normal. Unsuccessful treatment with oxygen, gavage feed- from mitral and tricuspid valve lesions of a ing, furosemide and digoxin was attempted. Postmortem findings confirmed subclinical seven-year-old female swan that cardiohepatomegaly and severe ascites. Histologic examination of the liver 36 revealed fibrosis that was thought to have occurred secondary to right ventricu- was found dead in her enclosure. Chicken em- bryos are classic experimental animals to study tera- tologic effects of drugs on the heart. Various cardio- vascular malformations can experimentally be induced, especially intraventricular septal defects. Spontaneous cardiovascular malformations like du- plicitas cordis, multiplicatis cordis, ectopia cordis have been reported. Intraventricular septal de- fects are usually functionally closed, but in two per- cent of cases the condition is associated with conges- tive heart failure. Blood is shunted from left to right, which leads to right ventricular failure and ascites secondary to valvular insufficiency.

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Other presenting Cloacal Stricture signs may include tenesmus 300mg allopurinol amex, melena buy 300mg allopurinol free shipping, foul-smelling Infections purchase 100 mg allopurinol otc, surgical manipulation of the cloaca (par- feces, flatulence, pasting of the vent and cloacoliths. Applying an acetic acid solution (apple ci- Cloacal impaction may occur from foreign bodies (eg, der vinegar) to cloacal epithelium will change the potato chunks in Galliformes), fecaliths, concre- color of papillomatous tissue to white. A definitive ments of urates and retained necrotic eggs (Figure diagnosis can be made after histopathologic exami- 19. Cloacal papillomas are often asso- thick concrements on the cloacal wall to solid masses ciated with similar lesions in the oropharynx, cho- the size of a chicken egg. In any case of cloacal ana, esophagus, crop, proventriculus, ventriculus and occasionally mucosa of the eye and nose. There seems to be a tation of the intestines as far proximal as the duode- high correlation between neoplasia of bile ducts and num. Renal failure and visceral gout may occur if the pancreatic ducts and papillomatosis in psittacine 51 birds. The referring veterinarian had placed a purse-string type suture to correct what was diagnosed as a cloacal prolapse three days before presentation. The purse-string suture was removed and the birdreleased a large quantity of excrement; however, the tenesmus continued. Survey radiographs revealed several elongated mineralized masses in the cloacal area (arrows). The papilloma was cauterized by specific application of silver nitrate, and the cloaca was flushed with a dilute povidone-iodine solution. Papillomas that protrude from the cloaca must not be confused with a cloacal prolapse, as initially occurred in this case. Various techniques have been used to treat cloacal papillomas, including cryosurgery, chemical cautery, radiosurgery and autogenous vaccination,173 but the The Pancreas reported spontaneous remissions and intermittent nature of the disease67,69,129,200 makes evaluation of the various treatments difficult. The introduction of birds with papillomas to a breeding facility should be Anatomy and Physiology prevented by performing a thorough physical exami- nation at the beginning and end of the quarantine The pancreas is situated on the left ventral side of period. Of 41 papillomatous lesions, growth was be- the abdominal cavity between the descending and nign in 40, but one single case was diagnosed as ascending loops of the duodenum. There are one, silver nitrate must come in contact only with the two or three pancreatic ducts, which usually drain tissue intended to be removed to prevent severe the pancreatic secretions into the ascending part of burns of normal cloacal mucosa (Color 19. The exocrine pancreatic enzymes that are present in the duodenum include amylase, lipase, trypsin and chymotrypsin, which facilitate degradation of carbohydrates, fats and proteins, re- spectively. Trypsin and chymotrypsin are secreted as inactive precursors, and they become active only when they enter the duodenum. The activator is the locally produced enzyme, enterokinase, which changes trypsinogen to trypsin. Many may occur as the result of a chronic inflammatory postmortem lesions have been reported in avian pan- process and cause clinical changes suggestive of pan- creata. If no pancreatic enzymes are studies on the relation between pancreatic disease available in the duodenum, maldigestion and pass- and plasma amylase and plasma lipase activities in ing of feces with excessive amylum and fat will occur. Fat in the feces can be amylase and lipase levels may respond to therapy demonstrated by Sudan staining. Pancre- such as fat, starch grains and muscle fibers is compli- atic fibrosis was reported in two psittacine birds with cated by variation in diets and by changes due to 70 chronic chlamydiosis. Measurement of fecal proteolytic activity can be performed in several High dietary levels of zinc may cause dilation of ways. The X-ray film gelatin digestion test is an acinar lumina and degenerative changes in acinar unreliable assay of fecal proteolytic activity. Dilatation of the small intestine may be synonyms including runting and leg weakness,104 visible due to an accompanying ileus. Increased runting syndrome,147 infectious stunting,19,171 pale plasma amylase activity (secondary to destruction of bird syndrome,65,116,142 malabsorption syndrome,142 exocrine pancreatic cells) has been reported in brittle bone disease,199 diarrhea and stunting,93 runt- chronic active pancreatitis in birds. Elevated plasma ing and stunting syndrome,165 and stunting and runt- amylase may also occur with occlusion of the main ing syndrome. Treatment should include withholding Although the etiology of this disease is not known, a food and oral medication for 72 hours, correction of virus is likely to be the etiologic agent,170 but myco- fluid and electrolyte balance and prophylactic use of toxins, other toxins, Campylobacter spp. Most birds develop enteritis and inflamma- tion of the pancreatic ducts and recover completely after a prolonged period of diarrhea. They have two pleural cavities and five flammatory reactions in the pancreatic ducts, which peritoneal cavities (Table 19. Clinically, these cavi- may result in complete blockage of the pancreatic ties dictate the location and spread of pathologic ducts in a small proportion of affected birds. Blockage processes within the coelomic cavity and are impor- leads to vacuolization and shrinkage of exocrine cells tant when considering surgical approaches to the and atrophy of the acini. The changes are similar to those induced after experimental ligation of the pancreatic ducts. The degree of develop a yellow-to-white chalky stool that contains obliteration of the pleural space depends on the spe- large amounts of starch. Histologically, the lesions tensive areas of pleural cavity persist in the adult (in can vary from a few lymphoid follicles to massive the chicken, dorsolateral). In can collapse inward when the pleural cavity is some cases, this is clinically manifested as pancreatic opened. Campylobacter infections in Estrildidae cause simi- The pericardium in birds is essentially similar to lar discoloration of the feces. Because the lungs are situated of the microvilli of the small intestine, which may dorsally and there is no diaphragm, the heart is not cause a malabsorption syndrome, can be found. The liver lies on both sides of the heart, and the parietal pericardium becomes con- Pancreatic Tumors tinuous with the peritoneum. During embryonic de- A high correlation between neoplasia of bile ducts velopment, the pleural cavity becomes separated and pancreatic ducts and internal papillomatous dis- 41,69,86,159 from the peritoneal cavity by the pulmonary fold, eases in psittacine birds has been suggested. The cranial and caudal thoracic air sacs develop as dilatations from the bronchi and penetrate into this double-layered sheet, splitting the dorsal from The Pleuro-peritoneum the ventral layer. The dorsal layer becomes fused with the adjacent wall of the thoracic air sac, be- comes tough and tendinous and acquires fascicles of 101,130 striated muscle along its lateral edge that attach to Anatomy and Physiology the ribs (costoseptal muscle). This is called the hori- The coelomic cavity in birds is subdivided by perito- zontal septum, saccopleural membrane or pulmo- neal, pleural and pericardial reflections into eight nary aponeurosis. The ventral layer becomes fused different cavities, excluding the eight cavities that with the ventral walls of the thoracic air sacs and is are formed by the air sacs. Peritoneal injuries normally heal The partitions in the peritoneal cavity proper are without the formation of adhesions, but in the pres- formed by five sheets of peritoneum which, apart ence of infection, ischemia or foreign bodies, fibrous from the mesentery, do not occur in mammals. The peritoneal surface allows the passive diffusion of water and solutes of low The combined dorsal and ventral mesentery form a molecular weight between the peritoneal cavities continuous midline vertical sheet from the dorsal to and the subperitoneal vasculature. Larger molecules the ventral body wall as far caudally as the ventricu- and particulate matter enter the bloodstream via the lus. The presence of free fluid in the peritoneal cavities is The posthepatic septum is composed of a left and a considered pathologic. It extends caudal to the From the anatomic relationships outlined above, it is liver from the last thoracic vertebra in a ventro- clear that diseases associated with the female genital caudal direction to the caudal wall of the peritoneum. Peritonitis The ventriculus is enclosed between the two layers of from gastric perforation may be restricted to the the left sheet of the posthepatic septum. Rupture of the liver can lead to accumula- pal peritoneal fat depot is located between the two tion of blood in one of the hepatic peritoneal cavities. The posthepatic septum (together with the Ascites mesentery) divides the peritoneum into three princi- pal cavities: the intestinal peritoneal cavity dorsome- Ascites is defined as the accumulation of serous fluid dially, and two lateral hepatic cavities that enclose within one or more of the peritoneal cavities and may the liver. The left and right hepatic cavities are fur- be caused by peritoneal and extraperitoneal diseases. Large with other peritoneal sheets (medially with the mes- amounts of ascitic fluid may compress the pulmonary entery, cranially with the parietal peritoneum, air sac system, causing dyspnea. The lymphatic vessels are small, the largest being hardly more than 1 mm in diameter, and the thoracic duct is only 1. These lipo- proteins have been defined as “portomicrons” in con- trast to “chylomicrons” (the fat-rich particles that are absorbed by mammals). Blockage of lymph drainage can be an important factor in the development of ascites in birds. For example, implantation of oviduct carcinoma on the intestinal peritoneal cavity rapidly induces ascites from portal hypertension secondary to pulmonary hypertension. Right ventricular failure with valvular insufficiency results in increased pressure in the vena cava where the lymph ducts connect to the circulatory system.

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Physiologic Marrow Ossification: During egg-lay- ing order allopurinol 300 mg fast delivery, there is a large increase in the quantities of In man and in dogs purchase 300 mg allopurinol otc, there are significant linear calcium and phosphorus that are retained from the relationships between calcium and albumin cheap 100 mg allopurinol with visa, and cal- diet and deposited in the medullary bone. In these species, adjustment medullary bone may completely fill the marrow cav- formulas have been derived for serum total calcium ity of long bones, particularly those in the limbs on the basis of the concentrations of albumin and (Figure 23. When the hen found between total calcium and albumin concentra- starts to secrete the eggshell, the medullary bone is tion in the plasma of 70 healthy African Grey Par- resorbed by osteoclastic activity. Approximately 14% of the variability of calcium ited in the eggshell as calcium carbonate, and the was attributable to the change in the concentration phosphorus is excreted from the body. A correction formula lary bone deposits should not be mistaken for a was derived on the basis of the concentration of pathologic condition radiographically. The precise de- albumin: tails of the hormonal mechanism by which the sup- Adjusted Ca (mmol/l) = Ca (mmol/l) - 0. Fruits and most vegetables are also The correlation between calcium and albumin was calcium deficient. Nonetheless, many pet food retail- significant, but significantly smaller than the corre- ers continue to market so-called “complete parrot lation between calcium and total protein. Only 11% foods,” which consist only of seeds (mainly sunflower of the plasma calcium concentration was attributable seeds). Affected birds have a low or normal plasma to a difference in concentration of albumin. In young in the Peregrine Falcon was derived on the basis of birds, rickets or rachitis is seen as a result of calcium- the total protein concentration. Application of a correction formula in African Grey Secondary hyperparathyroidism due to a renal disor- Parrots and Peregrine Falcons is indicated when der is well known in mammals and possibly occurs extremely low or extremely high plasma protein con- also in birds. Under these circumstances, a uret method is used with human protein as a stand- high plasma phosphate concentration may be seen ard, and albumin is calculated from total protein and due to decreased tubular secretion of phosphate. This condition has not Hyperparathyroidism is a condition whereby there is been reported in birds. In man primary hy- perparathyroidism may occur from hyperplasia, ade- Rickets noma or carcinoma of the parathyroid gland. The Rickets or rachitis is a metabolically induced bone most common presentation is a renal disorder due to disease in growing animals. The sec- cur throughout the skeleton, particularly in the ond most common presentation is bone disease proximal tibiotarsus, the head of the ribs and some- (osteitis fibrosa generalisata), while the third mode times the costochondral junction. Rick- hyperparathyroidism is a condition characterized by ets can be caused by inadequate dietary intake of hypercalcemia caused by the release of hormone-like calcium, phosphorus or vitamin D3 or by an improper substances from nonendocrine tumors; however, calcium:phosphorus ratio. With calcium and vitamin with neoplasm, hypercalcemia may also occur from D deficiencies, the resulting hypocalcemia induces widespread skeletal deposits of metastatic tumors, enlargement of the parathyroid gland (nutritional with associated increased osteoclastic activity. Consistent para- trary to the situation in man and domestic mammals, thyroid gland changes are not typical with a phos- primary hyperparathyroidism and pseudohyperpa- phate deficiency or excessive calcium intake. Tachypnea and polycythemia have been observed in Secondary nutritional hyperparathyroidism is com- birds with rickets, presumably because of poor rib monly reported in birds secondary to a calcium-defi- strength and infolding of ribs. The resorbed osseus tissue can be re- placed by fibrous tissue (osteodystro- phia fibrosa). The cortical bone can become so thin that spontaneous fractures may occur, especially in the vertebrae, ribs, tibiotarsus, tar- sometatarsus and femur. The frac- tures are typical for demineralized bone and are called “greenstick frac- tures. Plasma calcium concentrations remain gen- erally normal until the end stage of the disease, when tetanic convulsions may be observed. Although cal- cium deficiencies accompanied by pathologic frac- tures seem relatively common in psittacine birds, nutritional osteodystrophia fibrosa is rarely diag- nosed. A possible explanation might be that his- tologic examination of bones is not often performed. Osteoporosis To a certain degree, osteoporosis (cage layer fatigue) is physiologic during egg production. The hen had a three-year history of egg laying and had recently laid her second egg of the year. The bird appeared to have head tremors, was unable to stand and both wings were drooping. Histopathology indicated egg-related peritonitis, parathyroid hyperplasia and severe osteoporosis suggestive of secondary nutritional hyperparathyroidism. Etiologic factors may be immo- bilization, which is a well known cause for osteoporosis in man, and marginal nutritional calcium defi- ciency, which can alter the physi- ologic osteoporosis from high egg pro- duction into severe osteoporosis with associated clinical signs. Affected birds are found paralyzed in their enclosures, and have skeletal de- formities and enlarged parathyroid glands. Paralysis may be explained by spinal cord compression due to fractures in the thoracic spine and possibly by hypocalcemia, although the latter has not yet been demonstrated. Calcium nephropathy can also occur when birds are raised on diets containing 3% calcium instead of the normal 0. Hypocalcemia Syndrome in African Grey Parrots Hypocalcemia characterized by seizures has been described in raptors and African Grey Parrots. A unique feature of this syndrome in African Grey Parrots is that demineralization of the skeleton to maintain normal calcium levels does not occur. Hypo- calcemia is an important problem to consider in an African Grey Parrot that repeatedly falls off its perch. Administration of parenteral calcium and suf- ficient dietary uptake of calcium resolves clinical signs. A dietary calcium deficiency is suspected, but not confirmed as the etiologic agent. The higher incidence of hypocalcemia in dosteal bone formation and a distended abdomen secondary to African Grey Parrots might therefore be associated oviductal enlargement. These findings are suggestive of hyperes- with lower plasma concentrations of free calcium. Polyostotic Hyperostosis and polyostotic hyperostosis may be related, and the In female budgerigars, polyostotic hyperostosis (Fig- latter may be a pathologic exacerbation of a physi- ure 23. Hy- fication is often seen in association with ovarian perestrogenism has also been associated with ab- tumors. The basement membrane is in contact with the blood vessels, while the opposite cell membrane faces the colloid. Compared to the thyroid gland in mammals, the avian thyroid produces more T4 than T3. The activity of the 5’-monodeiodination sively enlarging abdominal mass, weight loss and a reduced fecal enzyme is hormonally controlled by hypothalamic output despite a normal appetite. Pathology Histologic examination of the thyroid gland is a use- ful and reliable means of differentiating between various thyroid disorders. The Thyroid Glands In primary hypothyroidism, there is a loss of follicles resulting either from thyroiditis or atrophy, while in secondary or tertiary hypothyroidism, the thyroid Anatomy and Physiology follicles are distended with colloid and the lining epithelial cells become flattened. The colloid is uni- The thyroid glands in birds are paired organs that lie formly dense with complete or nearly complete ab- on each side of the trachea in the thoracic inlet. A sence of resorption vacuoles at the periphery of the connecting isthmus is absent. Venous return is In endemic goiter (caused by iodine deficiency), the through the thyroid veins, which empty into the thyroid gland is diffusely enlarged because of cellular jugular vein. The ac- thyroid gland lacks calcitonin cells, which are located cumulation of thyroglobulin occurs because poorly in the ultimobranchial glands. Some thyroid areas The thyroid lobes are composed of follicles sur- may atrophy with concomitant fibrosis. The pathologic changes result in considerable Goiter in Budgerigars destruction of the thyroid. Lymphocytic infiltration The most frequent clinical disease of the thyroid of the thyroid gland is also a common finding with gland in birds is goiter in budgerigars, caused by leukosis in chickens, and it may be difficult to differ- feeding an iodine-deficient diet (usually seed mix- entiate autoimmune thyroiditis from leukosis. In budgerigars with goiter, clinical changes associated with tuberculosis or other chronic infec- are limited to regurgitation and dyspnea caused by tions, especially in Anseriformes. Specific signs of hypothyroid function are Normal thyroid histology is also dependent on the absent. The size of the tivity can be observed in molting pigeons: the height glands can exceed 10 mm compared to a normal size of the thyroid epithelium increases and colloid is 100 of about 2 mm, while the weight can show a 100-fold resorbed from the follicles. If the glands are cystic they may weigh 1000 mg and be palpable at Thyroid Disorders the thoracic inlet. Radiographically, a dorsal or ven- tral displacement of the trachea may be visible.

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