Case Challenge: An 8-Month-Old Chameleon With Anorexia & Lethargy
Date: September 22, 2020
Reviewed by: James Haberfield, BSc BVMS PGCBM MANZCVS (Medicine and Surgery of Unusual Pets, Avian Health)
Keywords: calcium, chameleon, metabolic bone disease
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Case Challenge
Solve the case: An 8-month old female veiled chameleon presents with a 3-day duration of anorexia and lethargy. Use history, physical examination findings, laboratory results, and survey radiographs to solve this case challenge.
Chief complaint: Anorexia and lethargy of 3 days duration in a chameleon | Staying at the bottom of the terrarium | Seems unable to use her tongue
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History
Diet: Gut-loaded crickets and locusts, every day except on Saturdays | Various vegetables offered every day | Calcium supplement dusted on insect preys twice a week | Water provided using a drip system
Housing: Large glass enclosure with natural branches and artificial and natural plants | Heating and ultraviolet (UV) lamps (distance between the UV lamp and the chameleon unknown by owner), both bought about 6 months ago | Misting of the terrarium about 3 times a day | No measurement of temperature or humidity
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Physical examination
Hands-off: Weak and reluctant to move
General examination: Moderately thin | Pink mucous membranes | No clinical dehydration
Coelomic palpation: Distended coelom with a large firm mass palpable caudally
Musculoskeletal examination: Left mid-shaft femoral fracture with marked instability | Bilateral mid-shaft humeral fractures
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Imaging
Dorsoventral and lateral views were taken. The dorsoventral view is presented here.
Numerous ovarian follicles were visualized on coelomic ultrasound.
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Laboratory Results
Plasma biochemistry result in an 8-month old female veiled chameleon (Chamaeleo calyptratus) Parameter Patient results Reported reference rangea Total calcium 36 mg/L 87 – 145 Phosphorus 114 mg/L 44 – 161 Uric acid 23 mg/L 0 – 219 a: Please refer to the references in the Case Challenge Discussion -
Problem List
- Anorexia
- Lethargy
- Inadequate husbandry*
- Multiples limb fractures
- Coelomic mass
- Severe hypocalcemia
- Decreased calcium:phosphorus ratio
- Generalized decreased bone density
- Pre-ovulatory follicular stasis
*Insufficient calcium supplementation for a juvenile, probably inadequate temperatures and humidity due to lack of measures, possibly insufficient UVB exposure
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Differential Diagnoses
On the basis of the history, physical examination, and laboratory results, is the diagnosis…
- Pre-ovulatory stasis (caused by absence of a suitable area for nest digging)?
- Renal secondary hyperparathyroidism?
- Nutritional secondary hyperparathyroidism?
- Traumatic fractures?
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The Answer
The best answer is NUTRITIONAL SECONDARY HYPERPARATHYROIDISM, also called nutritional metabolic bone disease. CLICK HERE to learn more.
- Pre-ovulatory (or follicular) stasis diagnosed in this patient is likely the consequence of the nutritional secondary hyperparathyroidism, as calcium is needed for egg shell production. Absence of suitable nest area is another common cause of pre- or post-ovulatory stasis.
- Renal secondary hyperparathyroidism is a common cause of generalized osteopenia and hypocalcemia. However, the disease is characterized by elevation of plasma phosphorus levels as phosphorus retention is the first consequence of the renal failure, causing the secondary hyperparathyroidism.
- Trauma could be the cause of the fractures identified in this patient. However, the severely decreased bone density suggests pathological fractures, which in this case are secondary to the nutritional secondary hyperparathyroidism.