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Vetdle Archive

Archive Case #220: Avian Hypovitaminosis A

Bird veterinary case - Easy - October 9, 2026

Clinical Clues

  1. Mango, an adult cockatiel, has been sneezing for weeks and is quieter than usual.
  2. Examination finds nasal discharge and poor feather condition, without a single obvious foreign body.
  3. The choanal papillae are blunted, and pale plaques line parts of the mouth.
  4. A detailed feeding history reveals an almost entirely seed-based diet, with no balanced pellets or vegetables.
  5. Histology of a sampled oral plaque shows excessive keratinisation and squamous metaplasia of the epithelium.
  6. Dietary assessment finds inadequate vitamin A intake; together with these epithelial changes, this supports a clinical diagnosis of hypovitaminosis A.

Diagnosis

Avian Hypovitaminosis A

Avian Hypovitaminosis A is supported by the deficient diet and epithelial changes. Oral plaques alone are not specific, and secondary infection can coexist rather than being excluded by this diagnosis. Remember: A bird's diet is part of the diagnostic history; mouth and airway problems are not always primarily infectious.

Learning review

Review the case evidence

Use the paired clues to explain how the evidence in this bird case supports the provided diagnosis, Avian Hypovitaminosis A, then compare your reasoning with the case explanation.

Evidence checkpoints

Clues 1-2

  1. Clue 1: Mango, an adult cockatiel, has been sneezing for weeks and is quieter than usual.
  2. Clue 2: Examination finds nasal discharge and poor feather condition, without a single obvious foreign body.

Clues 3-4

  1. Clue 3: The choanal papillae are blunted, and pale plaques line parts of the mouth.
  2. Clue 4: A detailed feeding history reveals an almost entirely seed-based diet, with no balanced pellets or vegetables.

Clues 5-6

  1. Clue 5: Histology of a sampled oral plaque shows excessive keratinisation and squamous metaplasia of the epithelium.
  2. Clue 6: Dietary assessment finds inadequate vitamin A intake; together with these epithelial changes, this supports a clinical diagnosis of hypovitaminosis A.

Self-review prompts

  1. After clues 1-2, what evidence from this bird case shaped your initial interpretation?
  2. When you compare clues 3-4 with clues 1-2, what changed in your reasoning about Avian Hypovitaminosis A?
  3. How do clues 5-6 align with the case explanation for Avian Hypovitaminosis A?

Educational Use

Vetdle archive cases are educational veterinary games for diagnostic reasoning practice. They do not provide veterinary advice, diagnosis, treatment, or professional medical guidance.