Difference between revisions of "Congenital and Neonatal Disease - Pathology"

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===[[Spina Bifida]]===
 
===[[Spina Bifida]]===
  
===Hydrocephalus===
+
===[[Hydrocephalus]]===
 
 
* Not uncommon in dogsand cats.
 
* Abnormal drainage of cerebrospinal fluid (CSF) results in dilation of the ventricles of the brain.
 
** Is a result of either stenosis of:
 
*** The aqueduct between the 3rd and 4th ventricle, or
 
*** The foramina further back in the brain stem.
 
** May also be acquired as a result of compression by tumours or infectious processes.
 
* Dilation of the ventricles with CSF causes pressure atrophy of the overlying brain tissue.
 
* Hydrocephalus can be seen at birth.
 
** Characterised by a dome shaped skull and open fontanelles.
 
* Hydrocephalus may also be hidden and detected later in life.
 
  
 
===Cerebellar Hypoplasia===
 
===Cerebellar Hypoplasia===

Revision as of 13:11, 15 February 2011

Introduction

  • Changes in the patterns of growth and differentation result in growth disorders.
    • These changes may be in single cells, tissues or organs.
  • There are two types of growth disorders.
    1. Malformations
      • Occur during gestation.
    2. Congenital
      • Detected at birth.
  • Some growth disorders have a heriditary input.
    • Occur as a result of genetically transmitted disease.
  • Some growth disorders occur as a sequl to a variety of insults to the foetus during gestation.
  • Only a few malformations are readily accessible to surgical correction.

Causes of Malformations

  • There are many causes of malformations in animals.
  • If the insult occurs early in gestation and is sufficiently severe, it will result in foetal death, resorption and infertility.
  • If the insult occurs late in gestation, the malformation will be more limited and the foetus usually survives.


Chromosomal Defects

Viral Diseases

  • Some viruses are able to cross the placenta and cause damage to foetal tissues.
  • For example:
    • Border Disease Virus in lambs.
    • Cerebellar hypoplasia in kittens caused by parvovirus.

Toxins

  • For example, toxic plants ingested by the dam during pregnancy.
    • Veratrum californicum
      • May produce cyclopia in lambs when ingested by the dam in early pregnancy.

Drugs

  • Griseofulvin
    • Used to treat "ringworm" (dermatophytosis). ( for the treatment of dermatophytosis - 'ringworm' )
    • Can cause serious malformations in kittens if administered to a pregnant queen.
  • Oestrogens and Actinomycin D have also been associated with malformations.

Ionising Radiation

  • For example, X-rays.

Nutritional Deficiencies

Copper Deficiency

Vitamin Deficiencies

  • Vit. A and D deficiency can result in skeletal malformations.

Physical Factors

  • For example, adhesions between foetal membranes or umbilical cord.
    • Can result in amputation of skeletal segments.
      • Especially around limbs.

Anoxia

  • Lack of oxygen in gestation can result in malformations.

Malformations

Cyclops

  • The presence of a single central eye as a result of facial deformity.

Bulldog Calf

Cleft Palate

Cystic Kidney

Spina Bifida

Hydrocephalus

Cerebellar Hypoplasia

  • The cerebellum is smaller than normal and oftenrudimentary.
  • Microscopy shows a highly disorganised architecture.
  • The animal shows tremors and ataxia.
  • Usually associated with viral infections during gestation.

Skeletal Malformations

  • There are numerous skeletal malformations.
  • Include:
    • Absence of bones
    • Deformation
    • Shortening
    • Duplication
    • Hypoplasia

Skin Defects

  • E.g. Epitheliogenesis imperfecta.
    • There is absence of portions of the epidermis.
      • Results in ulcers.

Muscular Defects

  • E.g. defects in the thoracoabdominal walls resulting in exterioration of internal viscera.
    • Called "shistosoma".

Cardiac Defects

  • There are several possible types of cardiac defects.
    • These include:
      • Patency between chambers
      • Persistent right aortic arch
      • Tetrology of Fallot.

Sexual Organ Malformation

  • E.g.:
    • Hermaphrodites
    • Pseudohermaphrodites
    • Freemartinism in females calves.

Metabolic Diseases

  • "Storage" diseases.
    • Vital enzymes are missing or defective within all cells.
  • These diseases express themselves as storage of intermediate products within cells.
  • Because neural tissue is a very sensitive tissue and cannot repair, these diseases usually express themselves as disease of the Central Nervous System.