Haematology

Question 1

Acute Chest Syndrome

Answer 1

The acute chest syndrome is a vaso-occlusive crisis of the pulmonary vasculature commonly seen in people with sickle cell anemia. This condition commonly manifests with a new opacification of the lung(s) on a chest x-ray.

Question 2

Define cryoglobulinaemia

Answer 2

Cryoglobulinemia is a medical condition in which the blood contains large amounts of pathological cold sensitive antibodies called cryoglobulins – proteins (mostly immunoglobulins themselves) that become insoluble at reduced temperatures.[1] This should be contrasted with cold agglutinins, which cause agglutination of red blood cells.

Cryoglobulins typically precipitate (clumps together) at temperatures below normal body temperature – 37 degrees Celsius (99 degrees Fahrenheit) – and will dissolve again if the blood is heated. The precipitated clump can block blood vessels and cause toes and fingers to become gangrenous. While this disease is commonly referred to as cryoglobulinemia in the medical literature, it is better termed cryoglobulinemic disease for two reasons: 1) cryoglobulinemia is also used to indicate the circulation of (usually low levels of) cryoglobulins in the absence of any symptoms or disease and 2) healthy individuals can develop transient asymptomatic cryoglobulinemia following certain infections.[2]

In contrast to these benign instances of circulating cryoglobulins, cryoglobulinemic disease involves the signs and symptoms of precipitating cryoglobulins and is commonly associated with various pre-malignant, malignant, infectious, or autoimmune diseases that are the underlying cause for production of the cryoglobulins

Question 3

What is Amyloidosis and what stain is used to identify it?

Answer 3

Amyloidosis is a group of diseases in which abnormal proteins, known as amyloid fibrils, build up in tissue.[4] Symptoms depend on the type and are often variable.[2] They may include diarrhea, weight loss, feeling tired, enlargement of the tongue, bleeding, numbness, feeling faint with standing, swelling of the legs, or enlargement of the spleen.[2]

There are about 30 different types of amyloidosis, each due to a specific protein misfolding.[5] Some are genetic while others are acquired.[3] They are grouped into localized and systemic forms.[2] The four most common types of systemic disease are light chain (AL), inflammation (AA), dialysis (Aβ2M), and hereditary and old age (ATTR).[2]

Diagnosis may be suspected when protein is found in the urine, organ enlargement is present, or problems are found with multiple peripheral nerves and it is unclear why.[2] Diagnosis is confirmed by tissue biopsy.

Stain: Congo Red

Question 4

What are Howell Jolly bodies?

Answer 4

A Howell–Jolly body is a cytopathological finding of basophilic nuclear remnants (clusters of DNA) in circulating erythrocytes. During maturation in the bone marrow, late erythroblasts normally expel their nuclei; but, in some cases, a small portion of DNA remains. Its presence usually signifies a damaged or absent spleen, because a healthy spleen would normally filter this type of red blood cell.

Question 5

What condition(s) are Howell Jolly bodies associated with?

Answer 5

Associated with markedly decreased spleen function. Essentially asplenism/hyposplenism. E.g. after splenectomy for conditions such as hereditary spherocytosis, trauma, autosplenectomy in Sickle cell, as well as Amyloidosis, MDS, megaloblastic anaemia.
Furthermore, hyposplenism is associated with coeliac disease.

Question 6

What types of infections does hyposplenism predispose to?

Answer 6

Pneumococcal, meningococcal

Question 7

What is Acute Intermitted Porphyria, how is it diagnosed and how is it treated?

Answer 7

Acute intermittent porphyria (AIP) is a rare autosomal dominant metabolic disorder affecting the production of heme resulting from a deficiency of the porphobilinogen deaminase. It is the most common of the acute porphyrias.

Diagnose: urine sample showing >5x normal levels of porphobilinogen, then confirm by measuring erythrocyte porphobilinogen deaminase activity

Treat: administer Dextrose + heme (Heamtin/Heme arginate)

Question 8

What are the 4P’s of Acute Intermitted Porphyria?

Answer 8

1. Painful abdomen (+ vomiting)
2. Peripheral neuropathy
3. Psychological disturbances (anxiety, psychosis)
4. Port wine colour urine

Question 9

Describe one way by which Acute Intermittent Porphyria can be distinguished from other porphyrias?

Answer 9

AIP does not cause any photosensitive cutaneous symptoms e.g. skin blistering when exposed to sunlight

Question 10

Treatment for essential thrombocythaemia?

Answer 10

Hydroxycarbamide, interferon-α and anagrelide can lower the platelet count. Aspirin can also be added to reduce clot formation, except when the platelet count is very high leading to a bleeding risk (via use up of vWF). Plateletphoresis is also an option

Question 11

What is the genetic mutation seen in Essential Thrombocythaemia?

Answer 11

JAK2