Regarding Hypersensitivity Reactions...

A 20-year-old woman had her ears pierced when she was 16 years old. Since that time, she has had only two pairs of earrings, both given to her by her parents; both were 18 karat gold. Last week her
21-year-old boyfriend gave her a new pair of earrings for Valentine’s Day, which she started to wear immediately. Three days later, she developed localized areas of erythema and vesicle formation where she had pierced her ears.

The mechanism responsible for this reaction most closely resembles which of the following?
(A) Type I hypersensitivity
(B) An Arthus reaction
(C) A positive purified protein derivative (PPD) skin reaction
(D) Antibody-dependent cell-mediated cytotoxicity
(E) An immune complex disease

Answer:

A young woman presents with a history of recurrent deep vein thrombosis presents with shortness of breath.

A 24-year-old nulliparous female with a history of recurrent deep vein thrombosis presents with shortness of breath.
The full blood count and clotting screen reveals the following results:
Hb 12.4 g/dl
Plateltes 137 WBC 7.5 * 109/l
PT 14 secs
APTT 46 secs

What is the most likely underlying diagnosis?
A. Third generation oral contraceptive pill use
B. Protein C deficiency
C. Antithrombin III deficiency
D. Antiphospholipid syndrome
E. Activated protein C resistance

Answer: D. Antiphospholipid syndrome

Discussion: The combination of a prolonged APTT and thrombocytopenia make antiphospholipid syndrome the most likely diagnosis.

Antiphospholipid syndrome

Antiphospholipid syndrome is an acquired disorder characterised by a predisposition to both venous and arterial thromboses, recurrent fetal loss and thrombocytopenia. It may occur as a primary disorder or secondary to other conditions, most commonly systemic lupus erythematosus (SLE) A key point for the exam is to appreciate that antiphospholipid syndrome causes a paradoxical rise in the APTT. This is due to an ex-vivo reaction of the lupus anticoagulant autoantibodies with phospholipids involved in the coagulation cascade

A Case Of Hereditary Angioedema

A 34-year-old female establishes care in your clinic. Her medical history consists of intermittent abdominal pain and episodes of angioedema in the past with unclear etiology. She has received multiple laparoscopic procedures that were unrevealing. During the initial interview, she relates several past episodes of lip and tongue swelling, for which she has not sought medical assistance. She has tried diphenhydramine without significant improvement. The swelling episodes resolve without intervention after 3–4 days.
Which of the following laboratory tests would be most helpful in establishing the diagnosis in this
patient?

A) ANA.
B) C3 complement level.
C) C4 complement level.
D) Complete blood count (CBC).
E) SS-A and SS-B.

Answer And Discussion

A 35 Year Old Man With Recurrent Infections

A 35-year-old male is seen by you in the hospital setting, after being admitted for pneumonia. Blood
cultures reveal Streptococcus pneumoniae. The patient was well until age 25 when he began having recurrent infections and developed an autoimmune hemolytic anemia. He also relates frequent sinus infections (real ones . . . not the kind we so often see) requiring antibiotics 8–10 times a year. His last bout of pneumonia required a stay in the ICU. You suspect immune deficiency in this individual.
What is the most useful test in making the diagnosis in this patient?

A) Complement levels.
B) Immunoglobulin levels.
C) CBC and differential.
D) Bone marrow biopsy.
E) Nitroblue tetrazolium test

Answer And Discussion: