Comparison of treatment protocols for removing metallic foreign objects from the ventriculus of budgerigars (Melopsittacus undulatus).
Foreign bodies (Medical care) (Health aspects)
Foreign bodies (Medical care) (Research)
Heart diseases (Care and treatment)
Heart diseases (Research)
Heart diseases (Diagnosis)
|Publication:||Name: Journal of Avian Medicine and Surgery Publisher: Association of Avian Veterinarians Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2009 Association of Avian Veterinarians ISSN: 1082-6742|
|Issue:||Date: Sept, 2009 Source Volume: 23 Source Issue: 3|
|Topic:||Event Code: 310 Science & research|
|Geographic:||Geographic Scope: United States Geographic Code: 1USA United States|
Abstract: To compare the efficacy of treatment protocols
recommended to aid passage of metallic foreign objects from the
ventriculus of birds, a 1-turn metal sphere, made from solder wire, was
placed into the crop of each of 44 budgerigars (Melopsittacus
undulatus). After survey radiographs confirmed the spheres were lodged
in the ventriculus, birds were divided into 6 groups. Each group
received 1 of 6 different treatment protocols: psyllium with grit,
acidic drinking water, fine grit, coarse grit, cathartic emollients
(peanut butter and mineral oil), and a control group. All birds were
treated simultaneously with a chelating agent, dimercaptosuccinic acid
(DMSA), to prevent heavy-metal toxicosis. Successive survey radiographs
were used to monitor elimination of the spheres from the digestive
tract. Of all protocols tested, birds treated with either fine or large
grit had the shortest mean elimination time of the metal spheres. These
results indicate that administration of grit particles, either fine or
coarse, appears to be effective in hastening the passage of metallic
foreign objects from the ventriculus of budgerigars.
Key words. lead toxicosis, foreign object, metallic, chelation, emollients, psyllium, grit, cathartic, avian, budgerigar, Melopsittacus undulatus
Ingestion of foreign objects containing heavy metals is a common clinical presentation in pet birds. These objects are ubiquitous in household environments, and birds often have easy access to them. The metals involved most frequently are lead and zinc, and common sources are soldering material used in cages, joints of Tiffany lamps, lead weights, leaded windows, and soldering wire. Lead and zinc are soft metals, and pieces are easily chewed off and ingested by psittacine birds.
Several protocols have been suggested for removing foreign bodies from the ventriculus of birds. Surgical removal is documented and effective but is a high risk to the patient. (2) Extraction using an endoscope involves less risk but cannot be performed on patients of small size. Effective medical management of these conditions is often mandatory in small birds, such as budgerigars (Melopsittacus undulatus). (3)
Medical management of heavy-metal toxicosis includes treatment with oral or parenteral chelating agents or both. One oral agent is dimercaptosuccinic acid (DMSA). Recommended dosages of DMSA in birds range from 25 to 35 mg/kg PO q12h given 5 days per week for 3-5 weeks. (4) DMSA administered orally at a dosage of 40 mg/kg q12h for 21 days has been found to be safe in cockatiels (Nymphicus hollandicus); however, DMSA was fatal to cockatiels when administered at a dose of 80 mg/kg q12h. (5)
Several medical protocols for foreign-body removal have been described. However, these protocols are not supported by any data and appear to result from empiric clinical experience. Furthermore, no comparative study has been done, to our knowledge, to evaluate these therapeutic options. (6) Treatment protocols proposed for accelerating the passage of foreign objects from the ventriculus include 1) oral administration of psyllium (hemicellulose), alone (7,8) or combined with grit, (9) in an attempt to bind particles and to increase gastrointestinal motility; 2) oral administration of acidic solutions (acetic acid) (10) to avoid dilution of gastric acids From the Montreal Bird and Exotic Veterinary Hospital, 6090 Sherbrooke St W, Montreal, QC H4A 1Y1, Canada. from drinking water and to try to maintain a low gastric pH, which facilitates the dissolution of the metal particles; 3) administration of emollient cathartics (peanut butter, mineral oil) (4,7) to bind the ingested particles and to lubricate their passage through the pylorus (6,11); and 4) administration of 3 to 5 particles of insoluble grit (crushed quartz, granite, silica) to aid in grinding the metal particles in the ventriculus down to a size that can be passed. (12)
The use of grit in the diet of pet birds has been controversial and has been advised against for many years. Excessive consumption, especially by birds given free access to it, can cause intestinal irritation and gastric impaction. (3,13,14) Grit has been shown to be unnecessary and of no value for digestion in canaries (Serinus canaria) (15) and psittacine birds. (16) Because of this, the value of grit, even as a therapeutic agent, may be underestimated.
In broiler chickens, dietary insoluble fiber (carboxy methylcellulose) slows digestive transit time and decreases absorption. (17) Furthermore, bulk dietary therapy with frequent high-fiber garage failed to remove a foreign body from the ventriculus of a yellow-headed Amazon parrot (Amazona ochrocephala oratrix). (18) In poultry, research has shown that the passage of a particle from the gizzard, through the pylorus, and into the duodenum depends on particle size. (19) The grinding action of the ventriculus eventually reduces most objects down to a size small enough to allow their passage through the pylorus and their elimination. Until that happens, birds must be treated with chelating agents, which can also have toxic effects. Therefore, accelerating the elimination of these foreign bodies is important.
In this study, we compared the efficacy of treatments that have been suggested as methods to help eliminate metallic foreign objects from the ventriculus of birds.
Materials and Methods
Forty-eight adult budgerigars were purchased from a local distributor for this study. The sex of the birds was not a criterion for selection. All birds appeared healthy at preliminary inspection. Preventive treatments for zoonotic and contagious diseases were administered as follows: doxycycline (Vibravenos, Pfizer GmbH, Karlsruhe, Germany), 100 mg/kg IM, repeated 4 times, at 7-day intervals; ronidazole (Ridzol 10%, Merck & Co, Whitehouse Station, N J, USA), in the drinking water, for 7 days; all birds were sprayed with a 0.09% pyrethrin-based spray (Hagen Bird Bath, RC Hagen Ltd, Montreal, Canada) to eliminate potential mite infestation; and ivermectin (Ivomec, Merial, Duluth, GA, USA), 200 [micro]g/ kg IM, was administered and repeated in 14 days. Pooled fecal samples were collected weekly throughout the study and were submitted for direct microscopic examination and for acid-fast testing. No parasites or acid-fast bacteria were detected. Survey radiographs were taken for baseline evaluation. Four birds with existing foreign objects or grit in their gizzards identified on survey radiographs were removed from the study.
Birds were provided with identical seed diets, as well as being fed commercial, formulated diets (Avicakes and Nutriberries, Lafeber Company, Odell, IL, USA); no grit or oyster shell was supplied. Birds were housed in identical cages (4 birds per cage) and environment. The birds were examined and weighed daily. Droppings were observed daily to monitor for signs of heavy-metal toxicosis (lethargy, vomiting, loose stool, loss of balance, weakness) or gastrointestinal disease that could interfere with the study.
Metal solder wire with a content of 60:40 lead zinc was used for the study. The solder was melted into small, spherical particles, which were then sorted by size, taped on to the cover of a radiographic cassette, and radiographed. A computer image of the film was analyzed, and uniform metal spheres, measuring 1 mm [+ or -] 0.1 mm in diameter, were selected for use in the study. One metal sphere was placed into the crop of each bird by oral intubation with a number 8 French rubber catheter. Both ventrodorsal and lateral view radiographs were taken 4 hours after intubation to confirm the presence of the metal sphere in the ventriculus.
The 44 remaining birds were randomly assigned to 5 groups of 8 birds and 1 group of 4 birds. Each group additionally received 1 of 6 treatment regimens. Birds in group 1 (n = 8) received fine, insoluble grit composed of silica (Riga, APAF, Ville St Laurent, Quebec, Canada), administered by oral intubation once (80 irregular particles, measuring approximately 0.2 mm each, to each bird), 24 hours after migration of the metallic sphere into the ventriculus. Psyllium (Metamucil, Procter & Gamble, Cincinnati, OH, USA) was then administered by oral intubation once daily (1 ml of a solution of one-half teaspoon of psyllium per 60 ml of water). Birds in group 2 (n = 4) received apple cider vinegar, added to drinking water (15 ml/L). Birds in group 3 (n = 8) received fine (small) particles of insoluble grit, composed of silica (Riga), administered by oral intubation once (80 irregular particles, measuring approximately 0.2 mm each, to each bird), 24 hours after migration of the metallic sphere into the ventriculus. Birds in group 4 (n = 8) received large (coarse) particles of insoluble grit composed of silica (Gravel with Oyster Shell, RC Hagen; oyster shell removed), administered by oral intubation once (20 irregular particles, measuring approximately 1-2 mm each, to each bird), 24 hours after migration of the metallic sphere into the ventriculus. Birds in group 5 (n = 8) received smooth peanut butter and mineral oil (1 ml of a mixture of 2:1 peanut butter:oil.) This mixture was administered by oral intubation q24h, 5 d/wk. Birds in group 6 (n = 8), the control group, received no treatment other than chelation therapy. All 44 birds were treated with chelation therapy (DMSA, 35 mg/kg PO q12h) to prevent heavy-metal toxicosis until the foreign body was eliminated.
Lateral radiographs of each bird were taken daily on 5 consecutive days out of 7 until the sphere was no longer visible on the radiograph. All birds with persisting metal in the ventriculus were observed daily for signs of heavy-metal toxicosis. Droppings were examined for signs of diarrhea or polyuria, and appetite and activity levels were assessed.
Results were tabulated and compared by using the total number and mean days to expulsion. The trimmed mean, which excludes outlying data points at the upper and lower limits of the array from the mean, were also calculated. For this study, an 80% trimmed mean was calculated. Statistical analysis of results was performed by using 1-way analysis of variance (Prism GraphPad Software, version 5, La Jolla, CA, USA).
No adverse effects to any of the treatment protocols were observed. All birds remained in good health throughout the study, and no symptoms of heavy-metal toxicosis were observed. Body weights remained stable. Only 2 birds (4.5%) exhibited transient signs of anorexia and loose stool: 1 in the control group, and 1 in the psyllium group. Several hens laid eggs during this study; the eggs were normal in size, shape, and shell thickness. No deaths occurred during this study.
The mean time of elimination, measured in days, for each group was compared with the control group. For control birds (group 6), mean elimination time was 63 days, whereas the trimmed mean was 75 days (Table 1; Fig 1). Of all treatments, birds administered psyllium combined with grit administration (group 1) had the longest elimination time as the birds passed the metallic sphere, on average, 14 days later than the control birds. The mean time for this group was heavily skewed by 1 bird, which eliminated the metal after 239 days. Reducing the impact of
outlying values, the trimmed mean elimination time for this group was shorter than that of the controls by 11 days. In birds given acidified water (group 2), the mean elimination time was the same as for control birds. Reducing the impact of outliers (100 days and 6 days) by using the trimmed mean had little effect on the results; metal spheres were eliminated only 3 days faster than they were eliminated in controls. In birds that received the emollient mixture of peanut butter and mineral oil (group 5), mean elimination time was 56 days, with a trimmed mean of 57, thus, respectively, 7 (mean) and 18 (trimmed mean) days faster than control birds. Fine grit administration (group 3) produced better results, with the birds eliminating the spheres in a mean of 36 days, 27 days faster than controls. In birds administered course grit (group 4), the mean time for elimination of metal spheres was 47 days, 16 days faster than the mean for the control group. However, trimmed mean elimination times for these 2 treatment groups (fine [group 3] and course grit [group 4]) were identical at 33 days, 42 days faster than controls. Although the difference in mean elimination time between groups appeared large, no statistically significant difference was found between treatment groups (P = .48).
[FIGURE 1 OMITTED]
In all cases, the metal spheres remained in the ventriculus until their disappearance, with no radiographic evidence of transit into the intestinal tract. The size of these spheres diminished over time in all birds, although over different time periods (Figs 2 and 3).
Several medical protocols are recommended anecdotally for removing ingested foreign bodies in birds. The object of this study was to verify the effectiveness of recommended protocols for eliminating foreign objects in the gastrointestinal tract of birds, keeping in mind that reducing length of treatment by even 1 week is important for client compliance and patient comfort. Our results show that mean time of elimination of a metal sphere from the ventriculus of budgerigars in both control and treated birds ranged from 36 to 77 days. Mean elimination time was shorter in birds administered either fine or large grit particles alone. Although the difference in mean elimination times between groups was not statistically significant, results may be clinically useful in managing cases of birds that have ingested heavy-metal particles.
There are practical and theoretical considerations for the treatment protocols used in this study. Oral administration of mineral oil will grease the bird's feathers and may be aspirated. The high fat content of peanut butter can be harmful to an already compromised patient. Acidified water may be ineffective in birds whose water consumption is minimal. Grit has been described as harmful, and the administration of psyllium is questionable, given that it has been shown to prolong transit time. (17) Because size constraints limit treatment for gastrointestinal foreign-body removal in small birds to medical management and because the speed of elimination is vital when the foreign body contains heavy metals, determining which treatment protocol is the most effective is essential.
[FIGURE 2 OMITTED]
During the course of this study, preventing the effects of heavy-metal absorption in the budgerigars was vital. Although calcium disodium edetate is an excellent choice for treatment of heavy-metal toxicosis, it is usually administered intramuscularly, which was not compatible with the long-term course of this study. Because DMSA is effective and can be administered orally with ease by the client in a home setting, it was chosen as the chelating agent for this study. However, possible adverse effects of prolonged use of DMSA are unknown. In this study, no overt adverse effects were observed with DMSA administered at 35 mg/kg PO ql2h for 34 weeks in budgerigars. Further, metal ingestion and chelation therapy did not hinder normal egg laying in several of the birds.
Birds were divided into groups of 8 except for 1 group of 4 birds. This was done for practical reasons because 4 birds with radiographic evidence of grit in their ventriculus were removed at the beginning of the study. Acid water was thought to be the least-effective treatment; therefore, only 4 birds were assigned to this group. Given that 2 out of 4 birds (50%) eliminated the foreign object at 72 days, and 1 (25%) at 100 days, it is unlikely, but unknown, whether adding more birds to this group would have resulted in different findings.
Radiographs were taken on 5 consecutive weekdays only. In birds in which no metal particles were visible radiographically on a Monday, a degree of error was inherent because birds could have passed the metal up to 60 hours previously. In each group, 1-3 birds showed no presence of metal on a Monday: 1 in group 1 (psyllium with grit; 13%), 1 in group 2 (acidified water; 13%), 3 in group 3 (fine grit; 38%), 2 in group 4 (large grit; 25%); and 2 in group 6 (control; 25%). To determine whether this factor would skew the results, we retabulated the data, subtracting 2 days from each of the Monday values in all the groups, but not from groups 3 and 4 (fine and large grit). Mean values for expulsion time remained considerably different between groups.
[FIGURE 3 OMITTED]
Although diagnostic radiographic standards require both ventrodorsal and lateral views, in this study, lateral radiographs alone were sufficient to verify the presence of the metal particle in the ventriculus. The ventriculus is easily identified on a lateral radiograph, and none of the radiographs showed metal in the intestinal tract.
Results of studies in poultry have shown that the size of a particle determines its ability to pass from the gizzard into the duodenum. Particles of greater than 3 mm are retained in the gizzard in poultry. (19) Although, no comparable study has been performed in psittacine birds, treatments aimed at reducing particle size should be effective.
Mean elimination times between treatment groups were not significantly different on statistical analysis. This result was not unexpected considering the small sample size, and significance may have been achieved with a larger number of birds in each group. Also, outlying values may have contributed to this outcome. A trimmed mean was, therefore, calculated to diminish the influence of outlying data, and results supported the trend observed in the mean values.
[FIGURE 4 OMITTED]
Mean elimination times in birds receiving psyllium combined with grit, those receiving acidified drinking water, and the control group were similar. Psyllium may act to bind the foreign object and facilitate its passage. However, psyllium may also reduce gut transit time, thus possibly slowing elimination. Furthermore, if the particle has not reached a size small enough for passage into the duodenum, psyllium may be of little use. Moreover, when grit is administered with psyllium, the grit may be retained in suspension in the gizzard, which would counteract its abrasive effect.
The purpose of acidifying the dinking water appears to be to prevent dilution of gastric acids by drinking water and to maintain a low gastric pH. This promotes acid digestion of the metal and reduces the particle size. The concentration recommended in this treatment protocol may be too low; however, at a higher concentration, palatability may be reduced and the advisability of long-term use of acidic drinking water (more than 2 months) is questionable. Furthermore, the efficacy of this treatment may be diminished because budgerigars are a desert species, and their water consumption is minimal.
Peanut butter and mineral oil treatment decreased the mean elimination time of the foreign object; however, administration was messy and the birds' feathers rapidly became oil soaked. This treatment would not be done easily in a home setting. Additionally, elimination of the foreign object was an average of 20 days longer than with grit.
The administration of grit, large or small, appeared to be the most effective method for eliminating a metal foreign object from the ventriculus of budgerigars in this study. The apparent higher efficiency of fine, compared with large, grit may be because of a greater abrasive effect by the fine grit. Although large grit has a larger surface, fine grit particles have more surface contact with the sphere. However, the trim means for elimination time with both sizes of grit were similar. Grit was administered 1 time only to these birds. Although free access to grit is not advisable, a weekly administration of grit may accelerate the passage of these metal objects.
In all birds, the size of the metal particles became smaller just before their disappearance on radiographs; therefore, passage through the pylorus appears to depend on particle size (Fig 4). Because no metal particles were observed on radiographs in the intestinal tract, transit through the intestines might have been very rapid with particles eliminated over a 1-day period. A less likely possibility is that particles dissolved completely within the ventriculus.
Delay in resolving a metallic foreign body ingestion is undesirable, given the stress involved in extended administration of chelation therapy. Treatment protocols should take into consideration ease of administration and patient comfort. Although results were not statistically significant, results of this study suggest that a 1-time, controlled administration of fine or large grit in budgerigars appears more effective and less injurious than other treatment protocols recommended for eliminating ingested metallic foreign bodies.
Corina Lupu, DVM, Dipl ABVP (Avian), and Stephanie Robins, BS
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Table 1. Number of days, mean number of days, and trimmed mean number of days elapsed before a metal sphere placed into the crop of budgerigars by oral intubation was eliminated from the ventriculus in groups with different treatment protocols. An 80% trimmed mean was calculated. Treatment groups 1 2 3 4 5 6 Peanut butter/ Psyllium/ Acidified Fine Large mineral grit water grit grit oil Control Bird Elimination of metal sphere (d) 1 45 6 6 75 78 9 2 41 72 31 33 41 78 3 82 72 35 53 66 77 4 239 100 34 33 84 99 5 14 -- 90 81 20 14 6 84 -- 66 31 52 73 7 20 -- 22 33 62 126 8 92 -- 7 33 43 28 Total (d) 617 250 291 372 446 504 Mean (d) 77 63 36 47 56 63 Trimmed 64 72 33 33 57 75 mean (d)
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