Age / Sex : 50 / F

Chief complaint: progressive weakness of both lower extremities

1) What is your impression?

Two weeks later, you can see the final diagnosis with a brief discussion of this case.

(Quiz는 quiz일 뿐이오니 답안은 한개만 보내주시기 바라오며, 복수의 답안을 보내주시는 분은 정답이 포함되어 있더라도 부득이 semi-correct answer로 처리토록 하겠습니다.)

Courtesy: 홍성환(Sung Hwan Hong), 서울대병원(Seoul National University Hospital)

Acute inflammatory demyelinating poly(radiculo)neuropathy (Guillain-Barre syndrome)

Discussion

Findings:

Slightly thickened, slightly T2 hyperintense ventral nerve roots in the cauda equina

Preferential contrast enhancement of ventral nerve roots in the cauda equina

Differential Diagnosis:

Subacute/chronic inflammatory demyelinating polyneuropathy

Carcinomatous or lymphomatous meningitis

Diagnosis: Acute inflammatory demyelinating polyradiculoneuropathy (or Guillain-Barre syndrome)

Discussion:

Guillain-Barre syndrome (GBS) is a clinical syndrome with acute demyelinating polyneuropathy. It is also known as ascending paralysis, acute inflammatory demyelinating polyradiculoneuropathy (AIDP), acute motor axonal neuropathy, and acute motor and sensory axonal neuropathy.

GBS is the most common cause of acute flaccid paralysis in humans. The incidence is 1 to 2 cases per 100,000 population per year, with all ages and races affected. The clinical presentation of GBS is symmetric, progressive motor weakness of more than one limb, with hyporeflexia or areflexia and little or no sensory changes (flaccid paralysis). Paralysis is frequently bilateral and symmetric. Cranial nerve and autonomic dysfunction are common. Respiratory paralysis may occur and require ventilatory support.

GBS is an immune-mediated attack on the myelin sheath of Schwann cells of motor (and less commonly, sensory) peripheral nerves. Genetics has not been firmly established, but there is probably an association between GBS and certain HLA subtypes. Frequently, there is a recognized antecedent illness. A number of viral and bacterial infections and vaccinations have been reported to precede development of GBS. The most commonly identified organism is Campylobacter jejuni. It is thought that certain lipopolysaccharides found on the outer surface of C. jejuni are similar in molecular structure to gangliosides on human nerve cell surfaces. After infection with C. jejuni, this “molecular mimicry” causes some subjects to develop antibodies against the lipopolysaccharides that cross-react with nerve cell gangliosides, leading to the immune-mediated attack against nerves.

Biopsy is rarely performed in GBS. Histologically, GBS is characterized by thickened nerve roots with focal, segmental demyelination. Axonal degeneration may also occur. There are perivascular and endoneural inflammatory infiltrates with lymphocytes and macrophages.

MRI is the imaging modality of choice, and patients with suspected GBS should have an MRI unless MRI is contraindicated. In patients with GBS, MRI may show slight, smooth enlargement and contrast enhancement of the spinal nerve roots of the cauda equina. There is preferential enhancement of the ventral (motor) nerve roots in most patients, so this pattern is strongly suggestive of GBS. The spinal cord is usually normal. There may be variable pial enhancement on the distal cord surface.

References:

1.     Smith JK. Inflammation of the spinal cord. In: Naidich TP, ed. Imaging of the spine. 1st ed. Philadelphia, Saunders Elsevier, 2011; 463-476.