This Week’s EMCQs – Week 8

QUESTION 1

A 45-year-old lady who is known case of SLE presents to Emergency department with lethargy and arthralgia.

Which one of the following test is indicative of disease activity?

A: Hypercomplementaemia

B: CRP <20 excludes the diagnosis

C: ESR <20 exclude the diagnosis

D: Elevated anti-dsDNA titres

A: Hypercomplementaemia

B: CRP <20 excludes the diagnosis

C: ESR <20 exclude the diagnosis

D: Elevated anti-dsDNA titres (Correct answer)

Commentary

Assessing SLE disease activity:

It is important to determine SLE disease activity in the ED. Useful symptoms of activity include mouth ulcers, alopecia and constitutional symptoms, as well as organ-specific symptoms, such as arthralgia or pleuritic chest pain.

Investigations used to assess disease activity include complement levels (low in active SLE), CRP and ESR (elevated), as well as anti-dsDNA titre. These are not diagnostic and many people with quiescent SLE may also have hypocomplementaemia or elevated anti-dsDNA titres.

A midstream urine for urinary sediment is an essential marker of renal involvement.

Reference: Textbook of adult emergency medicine, Cameron P et al, 4th edition.

QUESTION 2

A 60-year-old patient presents with inability to dorsiflex his ankle joint.

Regarding differentiation of isolated peroneal nerve injury from L5 injury, which one of the following findings on examination is suggestive of isolated peroneal nerve injury?

A: Patient able to invert foot

B: Numbness in 1st web space of the same side of foot

C: Patient able to evert foot

D: Patient able to extend his toes

A: Patient able to invert foot (Correct Answer)

B: Numbness in 1st web space of the same side of foot

C: Patient able to evert foot

D: Patient able to extend his toes

Commentary

Weakness of ankle dorsiflexors, toe extensors and ankle evertors is suggestive of a peroneal nerve lesion. Patients with a L5 radiculopathy will have similar deficits as those with a common peroneal nerve lesion, however, the tibialis posterior (a primary ankle invertor) is supplied by L5 through the tibial nerve so will be spared in a common peroneal nerve lesion, but it will be involved in L5 radiculopathy (with weakness of ankle inversion).