Question Four. 
A 22 year-old male is brought into the Accident and Emergency unit
following a road traffic accident. He is conscious, has a grey
complexion with cyanosed lips and fingers, is sweating, and complains
of feeling thirsty. His heart rate is 132 BPM and blood pressure is
108/52 mmHg. An open wound in the upper region of his right thigh is
bleeding despite a large quantity of dressing. The paramedics report
that he has had a major femoral artery bleed, which is ongoing.
Initial diagnosis is of severe haemorrhage resulting in ‘shock’. They
also add that despite a compound fracture of the right femur, the
patient reports no pain in the limb. He has been fitted with a neck
brace and a femoral splint.

Initial neurological tests show that the patient has normal sensory
and motor function in both arms. He is able to move his right leg
despite the broken femur, but has no sensation of pain in the leg and
in the right side of his abdomen and thorax. Conversely, he is unable
to voluntarily move his left leg.

a. With reference to the sensory and motor pathways in the central
nervous system, explain how you could reach a conclusion as to what
type of injury could have been sustained. Explain what other sensory
deficits and abnormalities you would expect to see in this individual.
(10 marks).

While in A+E, the patient is tested for his renal function. His plasma
creatinine concentration is analysed and found to be 105mmol/l.
Haematocrit is 42%. Over a 3 hour period he produces 0.15litres of
urine, which has a creatinine concentration of 2,583mmol/l.

b. Calculate GFR in ml/min. How does value this compare with normal
GFR? Calculate ERBF in ml/min. (5 marks).

c. It has been established that the patient is suffering from acute
haemorrhage. With reference to the GFR calculated above, explain how
the autonomic nervous system affects renal function in this type of
case. Explain the other renal mechanisms which help to maintain blood
pressure, volume and haematocrit in this patient. (10 marks).