A Grand Rounds neurology presentation given on 15/08/2014 at the University of Glasgow Small Animal Hospital demonstrating the approach to Toxoplasmosis through a case report of a one-year-old castrated male cat initially presenting with hindlimb ataxia and paresis, weightloss, and pyrexia.
2. ‘Kenzie’ McLaren
• One-year-old castrated male British Shorthair
• One-day history of hindlimb ataxia and paresis
• 20% weightloss in 11 weeks
• Initial PE: unremarkable
• PCV low: 22% [29-45%]
• Pelvic radiography unremarkable
• Referred to neurology service
4. Summary of Findings
• Pyrexia (39.3 to 40.3°C)
• Initial stiff hindlimb gait
• Reduced exercise tolerance: forelimbs became
stiff to the point of collapse
• Normal spinal reflexes, but some myoclonus
• No proprioceptive deficits
• Suggestive of a neuromuscular disorder
DDx: neuropathy, myopathy or junctionopathy
5. Summary of Findings
• Pyrexia (39.3 to 40.3°C)
• Initial stiff hindlimb gait
• Reduced exercise tolerance: forelimbs became
stiff to the point of collapse
• Normal spinal reflexes, but some myoclonus
• No proprioceptive deficits
DDx: neuropathy, myopathy or junctionopathy
6. Summary of Findings
• Pyrexia (39.3 to 40.3°C)
• Initial stiff hindlimb gait
• Reduced exercise tolerance: forelimbs became
stiff to the point of collapse
• Normal spinal reflexes, but some myoclonus
• No proprioceptive deficits
• Initial CK and ACh-R antibody (pending) tests
DDx: neuropathy, myopathy or junctionopathy
7. Electromyography (EMG)
• Abnormal spontaneous muscle activity
• Normal nerve conduction velocities
• Normal repetitive nerve stimulation
DDx: myopathy or junctionopathy
8. Problem List
Neurological
Ataxia
Stiff gate
Reduced exercise tolerance
Myoclonus (EMG confirmed)
Dx: Myopathy (idiopathic or secondary)
DDx: Infectious, Autoimmune, Neoplastic
Other
Weightloss (too acute)
Pyrexia
Anaemia (rarely)
CK elevated (84X upper ref.)
10. Blood Smear
• Anaemia poorly regenerative
• Howell-Jolly bodies in RBCs
• Occasional poikilocytes
• Mild toxic left shift
• Pro-eosinophils containing basophilic granules
• Occasional hyperchromatic lymphoid cells
• Direct Coombs Test Negative
DDx: chronic infectious, autoimmune, neoplastic
11. Biochemistry
• Hypoproteinaemia
• Low globulin levels
• High AST (2X upper ref.)
• High ALT (3X upper ref.)
• High CK (now 180X upper ref.)
• High fasting bile acids (2X upper ref.)
– Need bile acid stimulation test
DDx: myopathy, mild cholangiohepatitis
12. Biochemistry
• Hypoproteinaemia
• Low globulin levels
• High AST (2X upper ref.)
• High ALT (3X upper ref.)
• High CK (now 180X upper ref.)
• High fasting bile acids (2X upper ref.)
– Need bile acid stimulation test
DDx: myopathy, mild cholangiohepatitis
13. Thoracic Radiography
Excessive mild bronchial pattern
and cardiomegaly
L
R
DDx: chronic bronchitis, early onset asthma
DDx: myocarditis, HCM
14. Microbiology Report
• Mucal swab taken from endotracheal tube
due to respiratory noise during anaesthesia
• Culture: Gram negative cocci & large rods
• Sensitive to
– Clavunated amoxicillins
– Azithromycin
– Doxycycline
– Marbofloxacin
15. Problem List
Neurological
Ataxia
Stiff gate
Reduced exercise tolerance
Myoclonus (EMG confirmed)
Dx: Myopathy (idiopathic or secondary)
Dx: Mild cholangiohepatitis (potentially)
Dx: Chronic bacterial bronchitis
DDx: Infectious, Autoimmune, Neoplastic
Other
Weightloss
Pyrexia
Poorly regenerative anaemia
CK elevated (180X upper ref.)
Elevated liver enzymes
Cardiomegaly (DDx: myocarditis)
20. Continued Treatment & Monitoring
• Clindamycin 25 mg BID for 4 weeks
• Retest Toxoplasma antibody levels in 4 weeks
• Recheck biochemistry and haematology
• Ensure pulmonary infection has resolved and
hepatic markers are within normal limits
• Consider further cardiac evaluation
21. Toxoplasma gondii
• Worldwide zoonosis
• Obligate, intracellular
parasitic protozoan
• Only sexually reproduce in
cats – the definitive host
• Chronic infection can occur
for the lifetime of the host,
periodically rupturing cysts
and re-encysting to increase
numbers
Hypotonia = poor muscle tone
OOH = out-of-hours
Any way to find out the temperature, etc. that was monitored in the kennel?
Myoclonus = involuntary muscle twitching
Myasthenia gravis = type of junctionopathy (disease of the muscle or neuromuscular junction); autoimmune complexes block Ach-R function
Only a small blood sample was attainable
ACh-R Ab titre (80-96% sensitive) results take a few weeks to come back
Neuropathy = clinical signs rule out due reduced exercise tolerance and lack of proprioceptive and reflex deficits
Myoclonus = involuntary muscle twitching
Myasthenia gravis = type of junctionopathy (disease of the muscle or neuromuscular junction); autoimmune complexes block Ach-R function
Only a small blood sample was attainable
ACh-R Ab titre (80-96% sensitive) results take a few weeks to come back
Neuropathy = clinical signs rule out due reduced exercise tolerance and lack of proprioceptive and reflex deficits
Myoclonus = involuntary muscle twitching
Myasthenia gravis = type of junctionopathy (disease of the muscle or neuromuscular junction); autoimmune complexes block Ach-R function
Only a small blood sample was attainable
ACh-R Ab titre (80-96% sensitive) results take a few weeks to come back
Neuropathy = clinical signs rule out due reduced exercise tolerance and lack of proprioceptive and reflex deficits
Evaluates and records the electrical potential of skeletal muscle cells (depolarisation)
Identifies neuromuscular diseases, assesses pain, kinesiology, and motor control disorders
Myopathy more likely than a junctionopathy (myasthenia gravis) because of normal nerve conduction velocities and repetitive nerve stimulation
THEN, they ran a gambit of bloodwork
Howell-Jolly bodies = remnant DNA (suggests splenic damage)
Poikilocytes = abnormal-shaped RBCs
Toxic left shift = immature features still present in mature neutrophils with band neutrophils also present
Pro-eosinophils containing basophilic granules = often seen in chronic granulocytic leukaemia
CRONIC REGENERATIVE ANAEMIA (bone marrow exhausting)
Cholangiohepatitis? Shunts? Need a bile acid stimulation test.
Cholangiohepatitis? Shunts? Need a bile acid stimulation test.
Is the first radiograph a VD or DV, is it marked incorrectly or does it need to be flipped?
Congenital HCM based on age
Chronic bronchitis or early onset asthma
Vestigial 14th rib
Resp. noise during anaesthetic; the 5 days of antibiotics should have cleared up the infection
Titres can remain high years after exposure
All of these diagnoses are possible secondary to chronic Toxoplasmosis in transplacentally-acquired infection.
Do we need to retest of Abs can stay in the system years after infection?