Y2 OCaPE: NSB8 Muscle Weakness

Tendon tap reflex (1)

AKA Deep Tendon Reflex/ Myotatic Reflex/ Muscle Stretch Reflex

AKA knee jerk or biceps stretch 

Describe how you would carry out this test and what myotome you are testing ?

Either of the following (5 marks): 

BICEP 

• Patient has straightened arm, 
• place your thumb over the tendon area. 
• Hit with tendon hammer
• Biceps should contract, (elbow joint should pull back)
• forearm should flex (rotation)
• You are testing C5-C6 

OR KNEE JERK REFLEX 

• Strike below the patella with tendon hammer  

• Tap briskly 

• Lower leg should extend outwards 

• L3-L4 (L3/L4 kick the door)

What fibres are responsible for this reflex and what is their role?

1a afferents.

These report dynamic changes – e.g. report  velocity of length change. Maintain length of spindle via muscle  stretch reflex (monosynaptic activation of motor neurones) . 

Stabilises the muscle (3) 

The patient has a weak tendon tap reflex. What is this symptom  called? 

Flaccid paralysis (LMN signs) (2)

You take the following lab tests.

HbA1c: 4% 

Hb : 13.5g/dL 

Anti-AChR Ab : Negative 

Anti-ganglioside antibody: negative 

WBC: 718 

CSF 

Appearance: Clear 

Combining the above results  with the symptoms and weak tendon tap, what is the most likely diagnosis?

Must give correct diagnosis with explanation for (4 marks)

• Poliomyelitis – due to high WBC (infection)
• Polio grows in the spine and can kill a motoneurones, leading to flaccid paralysis
•  anti-achr-ab negative rules  out myasthenia which can also cause LMN signs  .
• Negative for anti-ganglion antibodies suggests it is not guillan-barre syndrome

Three days later, the patient has symptoms of a fever, vomiting,  a stiff neck and hurts when looking at light. Explain the  pathology?

Patient has developed meningitis.

Polio can also cause (viral) meningitis  (2)

Label the three layers of the meninges below

From top to bottom  (scalp to brain):

Dura, Arachnoid, Pia (2)

Describe how polio can be prevented?

Live oral polio vaccine (1)

• Produces IgA & IgG
• Attenuated via tissue