Reproductive and Genetic Diseases powerpoint

Reproductive and Genetic Diseases Study Notes

Reproduction Terminology

Root Words

  • cervic/o - narrowing, cervix
  • colp/o - vagina
  • episi/o - vulva
  • galact/o or lact/o - milk
  • gravid/o - pregnancy
  • mamm/o or mast/o - mammary gland
  • metr/o - uterus
  • omphal/o - umbilicus
  • orchid/o - testicle
  • ovari/o - ovary
  • phall/o or priap/o - penis
  • prostat/o - prostate
  • salping/o - oviduct

Reproductive Terminology

  • Breech presentation - abnormal posterior-first position of fetus at birth
  • Ectopic pregnancy - implantation of the embryo at an abnormal site (outside of the uterus)
  • Paraphimosis - narrowing of the prepuce, swelling the glands and preventing retraction
  • Cesarean section - C-section; delivery of offspring through an incision in the abdominal and uterine walls
  • Pseudocyesis - pseudopregnancy; false pregnancy
  • Colostrum - first milk-like substance produced by the female after parturition; it is thick, yellow, high in protein and antibodies

Reproductive Diseases Covered

  • Vaginitis
  • Pseudopregnancy
  • Eclampsia
  • Pyometra
  • Dystocia
  • Inappropriate Maternal Behavior
  • Lactation Disorder
  • Benign Prostatic Hyperplasia
  • Prostatitis
  • Prostatic Abscess
  • Prostatic Neoplasia
  • Priapism and Paraphimosis
  • Neoplasia of the Testicles
  • Penile, Preputial, and Scrotal Tumors
  • Transmissible Venereal Tumor (TVT)
  • Tumors of the Female Genital Tract
  • Tumors of the Mammary Gland

Diseases of the Female Reproductive Tract

Vaginitis

  • Common in puppies before first heat
  • Clinical signs: Yellowish vulvar discharge
  • Treatment: Keep them clean; usually resolves after the first estrous cycle without treatment; +/- Antibiotics

Pseudopregnancy (Pseudocyesis)

  • Occurs due to normal hormones of estrus; some dogs exhibit signs of pregnancy when they are NOT pregnant, typically 6 to 12 weeks after estrus lasting 1 to 3 weeks.
  • Clinical signs:
    • Weight gain
    • Mammary gland enlargement and lactation
    • Mucoid vaginal discharge
    • Behavior such as carrying stuffed toys and increased maternal behaviors
  • Treatment:
    • Signs are usually self-limiting
    • Remove any toys treated as puppies
    • Possible Ovariohysterectomy

Eclampsia

  • Emergency condition due to low blood calcium levels in nursing dogs; common in small and medium breeds.
  • Clinical signs:
    • Nervousness
    • Tremors
    • Ataxia
    • Seizures
    • Salivation
    • Stiff gait
  • Diagnosis:
    • Based on history and clinical signs alongside hypocalcemia
  • Treatment:
    • Immediate slow IV administration of 10% or 20% calcium gluconate
    • Monitor heart rate for bradycardia or arrhythmias
    • Oral calcium supplements after clinical signs regress
    • Can recur with subsequent pregnancies; ideally avoid breeding affected dogs
    • Prevention by good prenatal nutrition and calcium supplementation

Pyometra

  • Accumulation of pus in the uterus due to bacterial infection resulting from increased progesterone levels in intact females, typically affecting middle-aged or older intact female dogs and cats.
  • Types:
    • Open pyometra – cervix is open
    • Closed pyometra – cervix is closed
  • Clinical signs:
    • Vulvar discharge (open pyometra)
    • Abdominal enlargement
    • Vomiting
    • Lethargy
    • Polyuria (PU) or polydipsia (PD)
    • Dehydration/Azotemia
    • Febrile
  • Diagnosis:
    • Imaging: abdominal radiographs or ultrasound
    • Complete blood cell count (CBC): expect leukocytosis, neutrophilia with a left shift, dehydration
    • Serum chemistry: can indicate increased alkaline phosphatase levels and increased blood urea nitrogen
    • Vaginal cytology may reveal degenerative neutrophils, endometrial cells, and bacteria; indication of dilated, fluid-filled uterus
  • Treatment:
    • Ovariohysterectomy is the preferred treatment
    • Correct dehydration and azotemia before surgery
    • Administer broad-spectrum antibiotics
    • If still breeding, medical treatment options include Prostaglandin F2α (Lutylase)
    • Prevention: Ovariohysterectomy

Dystocia

  • Defined as difficulty giving birth which can arise from various factors:
    • Large fetuses (e.g., fetal anasarca or hydrocephalus)
    • Abnormal positioning (transverse presentation)
    • Narrow birth canal
    • Uterine inertia (failure of coordinated contractions or exhaustion)
  • Clinical signs:
    • Bitch or queen in labor for longer than 4 hours without delivering a fetus
    • Green vaginal discharge during parturition
    • More than 1 hour between births
  • Diagnosis:
    • Physical examination with digital palpation of vagina
    • Radiography to determine fetal position, size, and number
    • Ultrasonography to check fetal viability and distress
  • Treatment:
    • Manual manipulation if a fetus is lodged
    • Administer fluids and dextrose, +/- oxytocin
    • Cesarean section if medical treatment fails

Inappropriate Maternal Behavior

  • Normal behaviors include nursing, retrieving, grooming, and protecting; however, some animals fail to exhibit appropriate behaviors.
  • Clinical signs:
    • Mother appears restless
    • Constant crying from neonates
    • Mother may attack or kill her young
  • Diagnosis: Observation of maternal behavior
  • Treatment:
    • Tranquilization with acepromazine or diazepam
    • Early weaning of offspring or bottle feeding might be necessary

Lactation Disorders

  • Mastitis - septic inflammation of the mammary gland, most common lactation disorder
  • Agalactia - absence of milk production due to factors like stress, malnutrition, premature parturition, or infection
  • Galactostasis - condition where milk is not expelled timely, potentially causing painful engorgement
  • Clinical signs:
    • Mammary discomfort or reluctance to nurse
    • Firm, hard, red swelling(s) in glands
    • Discolored milk
    • Fever
  • Diagnosis:
    • CBC
    • Milk cytology and culture/sensitivity
  • Treatment:
    • Broad-spectrum antibiotics
    • Warm compresses followed by milking of affected glands
    • Possible cabbage wrap
    • Severe cases may require hospitalization, IV fluids, or surgical debridement

Diseases of the Male Reproductive Tract

Benign Prostatic Hyperplasia (BPH)

  • Non-cancerous enlargement of the prostate gland associated with testosterone; it is the most common prostate disease.
  • Clinical signs:
    • Weak urine stream or straining to urinate
    • Tenesmus (straining to defecate)
    • Some dogs may be asymptomatic
  • Diagnosis:
    • Physical examination (digital rectal examination)
    • Ultrasound as necessary
  • Treatment:
    • Castration leads to a 70% reduction in gland size within 7 to 14 days
    • Finasteride may be considered for breeding dogs

Prostatitis

  • Occurs due to bacterial infection, predisposed via urinary system or direct infection of the gland.
  • Clinical signs - Acute:
    • Anorexia
    • Fever
    • Lethargy
    • Stiff gait in rear limbs
    • Caudal abdominal pain
  • Clinical signs - Chronic:
    • May be asymptomatic or intermittent urinary issues
  • Diagnosis:
    • Urinalysis showing blood, increased WBC count, presence of bacteria
    • Digital rectal examination
    • Urine culture and sensitivity
  • Treatment:
    • Antibiotics based on culture/sensitivity results
    • Castration may be beneficial

Prostatic Abscess

  • Serious form of prostatitis leading to pus-filled pockets in the gland.
  • Clinical signs:
    • Tenesmus
    • Urethral discharge
    • Lethargy
    • Pain
    • Vomiting
    • Hematuria
    • Fever
    • Depression
  • Diagnosis:
    • CBC and serum chemistries show possible leukocytosis or normal WBC count; elevated liver enzymes, +/- hypoglycemia, and hypokalemia
    • Prostatic aspiration yields hemorrhagic, purulent, septic fluid
  • Treatment:
    • Surgical drainage
    • Castration
    • Antibiotic therapy (e.g. fluoroquinolones)

Prostatic Neoplasia

  • Uncommon in dogs but occurs in cats; always malignant regardless of intact or neutered status.
  • Clinical signs: Similar to other prostatic diseases, often presented late in the disease.
  • Treatment and prognosis: Poor prognosis; advanced and aggressive nature often limits options.

Priapism and Paraphimosis

  • Priapism - a persistent, abnormal erection of the penis, potentially painful; may also lead to embarrassment or pain for the dog.
  • Paraphimosis - inability to retract the penis into the preputial sheath.
  • Treatment:
    • Acute cases require sedation
    • Remove any causative agents
    • Immerse tissue in cold hypertonic glucose solution to reduce swelling
    • Gently clean the penile tissue

Neoplasia of the Reproductive Tract

Neoplasia of the Testicles

  • Testicular tumors account for approximately 5% to 15% of tumors in male dogs; highest incidence in cryptorchid dogs or those with inguinal hernias; typically seen in older intact males (9–12 years).
  • Clinical signs:
    • Non-painful testicular enlargement may be present
    • Feminization symptoms in dogs with Sertoli cell tumors (25% to 50% of cases): non-pruritic alopecia, hyperpigmentation in the inguinal region, gynecomastia, non-regenerative anemia, thrombocytopenia.
    • Enlarged lymph nodes in some cases (10%–20%).
  • Treatment:
    • Castration is the treatment of choice

Penile, Preputial, and Scrotal Tumors

  • Most common neoplasia involves the transmissible venereal tumor (TVT) seen primarily in dogs, particularly in temperate climates with large free-roaming populations; spread during sexual contact and can be transmitted through licking/sniffing.
  • Clinical signs:
    • Penis, prepuce, or scrotum may show tumors resembling cauliflower-like masses; can bleed easily and are friable.
  • Diagnosis:
    • Cytology via impression smears reveal large, round to oval cells with abundant pale cytoplasm; often many vacuoles and frequent mitotic figures in nuclei.
  • Treatment:
    • TVTs may regress spontaneously with adequate tumor stimulation
    • Surgical removal or chemotherapy may be options

Tumors of the Female Genital Tract

  • Types include ovarian tumors, uterine and cervical tumors, vaginal and vulval neoplasia, and tumors of the mammary glands; vaginal and vulvar tumors are commonly seen in the female genital tract in dogs.
  • Clinical signs:
    • Pedunculated masses may protrude from the vulva
    • Symptoms such as perineal swelling, vaginal discharge, dysuria, or constipation can arise.
  • Treatment:
    • Surgical removal with ovariohysterectomy to prevent recurrence

Tumors of the Mammary Gland

  • Most common tumor in female dogs.
  • Risk factors:
    • 0.5% for bitches spayed before first estrus
    • 8% for those spayed after one estrus cycle
    • 26% for those spayed after two or more cycles
    • Approximately 50% of tumors in dogs are benign; in cats, only 10% to 20% are benign.
  • Clinical signs:
    • Firm nodule palpable in mammary chain or gland
    • Enlarged lymph nodes in the region may be noted
  • Diagnosis:
    • Physical examination and potentially CBC, serum chemistries, thoracic radiographs pre-surgery
  • Treatment:
    • Surgical removal required

Genetic Diseases

Overview

  • Genes provide the blueprint for life, defining characteristics of organisms. When a gene is defective, it can lead to diseases. By studying genetics, we can predict the incidence of diseases and manage the spread of defective genes through informed breeding practices.

Genetics Terminology

  • Punnett square - a grid to predict the genotypes and phenotypes of offspring
  • Phenotype - actual genes an animal carries for a particular trait
  • Genotype - actual physical appearance resulting from genotype; designated by two letters.
  • Alleles - variants of the same gene that govern a trait; one from mother, one from father.
  • Homozygous - both alleles are identical.
  • Heterozygous - both alleles are different.
  • Dominant - trait expressed with at least one copy of the allele; designated with a capital letter.
  • Recessive - both alleles must be present for the trait to be expressed; assigned a lowercase letter.

Genetic Diseases Covered

  • Von Willebrands Disease (vWD)
  • Polycystic Kidney Disease (PKD)
  • Progressive Retinal Atrophy (PRA)
  • Patent Ductus Arteriosis (PDA)
  • Canine Hip Dysplasia

Von Willebrand’s Disease (vWD)

  • The most common bleeding disorder in dogs, resulting from a decrease in von Willebrand’s Factor (vWF) which is vital for blood clotting, leading to hemorrhage.
  • Breed disposition: Dobermans, German Shepherds, Poodles, Golden Retrievers, Shelties
  • Inheritance: Autosomal dominant trait with incomplete inheritance.
  • Clinical signs:
    • Easy bruising in predisposed breeds
    • Prolonged bleeding during estrus
    • Prolonged bleeding from venipuncture.
  • Diagnosis:
    • Buccal mucosal bleeding time (BMBT)
    • VWF levels
  • Treatment:
    • Severe hemorrhages might require fresh frozen plasma or whole blood transfusions and/or DDAVP (a clotting promoter) to increase vWF.
  • Prevention: Affected dogs should not be used for breeding.

Polycystic Kidney Disease (PKD)

  • Characterized by formation of small fluid-filled sacs in the kidney leading to renal failure.
  • Breed predilection: Primarily in Persians, also Himalayans and British Shorthairs.
  • Inheritance: Autosomal dominant trait.
  • Diagnosis: Genetic testing or abdominal ultrasound.
  • Treatment: Management of kidney failure.

Progressive Retinal Atrophy (PRA)

  • Leads to degeneration of the retina and potential vision impairment or blindness.
  • Breed predilection: Toy Poodles, Miniature Poodles, Golden Retrievers, Irish Setters, Cocker Spaniels, Miniature Schnauzers, Collies, Samoyeds, Gordon Setters, Norwegian Elkhounds.
  • Inheritance: Autosomal recessive trait.
  • Clinical signs:
    • Defective night vision
    • Gradual loss of day vision
    • Possible cataract formation

Patent Ductus Arteriosis (PDA)

  • A congenital heart defect in juvenile dogs where the ductus arteriosus, a temporary fetal blood vessel, fails to close at birth. This causes left to right blood shunting.
  • Breed predilection: Chihuahuas, Collies, Maltese, Poodles, Pomeranians, English Springers, Keeshonds, Bichons Frises, Shetland Sheepdogs.
  • Diagnosis:
    • Loud heart murmur
    • Thoracic radiography
    • Electrocardiography (ECG)
    • Echocardiography
  • Treatment:
    • Surgical intervention
    • Endovascular stenting or coil placement to close PDA

Canine Hip Dysplasia

  • A common condition affecting the canine hip where the femoral head does not fit snugly into the acetabulum, leading to joint damage.
  • Contributing factors: Genetic predisposition, environmental influences, dietary factors, and muscle mass disparity.
  • Clinical signs:
    • Difficulty rising, stiffness, pain upon hip joint palpation
    • Older dogs may exhibit lameness, waddling gait, and muscle atrophy in thighs
  • Diagnosis:
    • Pelvic radiographs
    • Orthopedic Foundation for Animals (OFA) Certification
    • The Penn Hip Method
  • Treatment:
    • Conservative approach: moderate exercise, weight management, anti-inflammatory medications, nutriceuticals
    • Surgical options: Femoral head ostectomy (FHO), total hip replacement, or triple pelvic osteotomy

Punnett Squares

Introduction

  • Through genetics, Punnett squares are utilized to predict gene transmission and phenotypical expression in offspring.

Simple (Autosomal) Dominance

  • An allele is entirely expressed whenever present in the genotype.
  • Example: The dense pigment gene (A) in black cats.
    • A = dark hair coat pigmentation (black)
    • a = dilute hair coat pigmentation (blue)

Example Calculation

  • Crossing a heterozygous black mother (Aa) with a heterozygous black father (Aa).
    • Structure of the Punnett square with maternal alleles over columns and paternal alleles at the beginning of rows:
    • Mother:
      • A
      • a
    • Father:
      • A
      • a

Result of Punnett Square

  • Genotype results:
    • 25% chance of AA
    • 50% chance of Aa
    • 25% chance of aa
  • Phenotype results:
    • 75% of offspring black
    • 25% blue

Conclusion

  • These notes provide a comprehensive outline of reproductive and genetic diseases in canines, including terminology, specific diseases, their clinical signs, diagnosis, and treatment protocols.