The following blood films have characteristic features. For each case, the cell counts are provided, along with the blood film comment. For each set of results, determine the most likely diagnosis.
To see the results click the result button.
Case 1: 18 year old woman, blood test prior to year in Germany as an
AFS exchange student. Clinical examinination: NAD.
Cell Counts
Hb:
132 g/L
N
PCV:
0.36
N
MCV:
85 fl
N
MCH:
28 pg
N
WBC
5.9 × 109/L
N
Plt:
286 × 109/L
N
Blood film:
RBC morphology: normocytic, normochromic.
WBC morphology: within normal limits.
Platelet morphology: within normal limits.
Case 1: Normal blood film
Note red cells of fairly even size, shape, colour and area of central pallor.
Case 2: 67 year old man complaining of tiredness and lightheadness. Clinical examination: appears pale otherwise NAD, Meds: phenytoin – last 15 years, Social hx: widowed, poor nutrition
Cell Counts
Hb:
79 g/L
PCV:
0.23
MCV:
114 fl
MCH:
37 pg
WBC
6.2 × 109/L
N
Plt:
219 × 109/L
N
Blood film:
RBC morphology: normochromic, macrocytosis +++, anisocytosis +++, numerous oval macrocytes, occ teardrops and fragments. WBC morphology: many neutrophils show nuclear hypersegmentation. Platelet morphology: within normal limits.
Case 2: Megaloblastic anaemia caused by folate deficiency
This picture is characteristic of a megaloblastic anaemia, which are most frequently caused by either vitamin B12 or folate deficiency. The CBC may reveal a number of distinctive changes, for example, the haemoglobin will be low, and MCV and MCH both elevated, the blood film may reveal oval macrocytes (instead of round), and hypersegmented neutrophils (often present in nutritional megaloblastic anaemias). Tests for vitamin B12 and folate should be requested for confirmation.
For this case, phenytoin is known to interfere with folate utilisation, and in combination with the recent poor diet, folate deficiency has developed. Folate deficiency can develop faster than B12 deficiency, with most people having stores for 6 months compared to 3–6 years for vitamin B12. Adequate folate intake can restore folate levels within a few days.
Case 3: 19 year old male, fatigue, sore throat and fever. Physical exam: enlarged tonsils, swollen cervical lymph nodes.
Cell Counts
Hb:
154 g/L
N
PCV:
0.46
N
MCV:
88 fl
N
MCH:
29 pg
N
WBC
12.9 × 109/L
Plt:
333 × 109/L
N
WBC differential: N 24%, L 73%, M 0%, E 3%, B 0%
Blood film:
RBC morphology: normochromic, normocytic. WBC morphology: most of the lymphocytes are large variant cells. Platelet morphology: within normal limits.
Case 3: Infectious mononucleosis
The presence of a lymphocytosis with variant lymphocytes in a patient aged 10 to 30 years with sore throat, fever and fatigue is highly suggestive of infectious mononucleosis, and some believe this presentation is diagnostic. However, if the diagnosis is still uncertain, additional tests are available. Heterophilic antibodies (Paul Bunnel, Monospot) will test positive in 90% of people by the third week of illness, persisting for 3–6 months. Where clinical suspicion is high and heterophilic antibodies continue to test negative, EBV antibodies may be requested (although these are considerably more expensive). The presence of IgM antibodes indicate current or recent infection, while IgG antibodies persist for life.
Drug induced agranulocytosis
The consequences of drug-induced agranulocytosis can be life threatening, but it is reassuring that it is a relatively rare occurrence. A recent systematic review1 has revealed 125 drugs that either definitely or probably cause acute agranulocytosis. Although different sources mention different drugs, those most often associated with a higher risk of agranulocytosis include: carbimazole, clozapine, sulphasalazine, gold salts, penicillamine and clopidogrel.2 In most cases, drug induced acute agranulocytosis occurs within the first three months of starting the drug.
The onset of agranulocytosis is abrupt and patients receiving medications associated with high risk should be warned to seek medical advice urgently if they develop fever, sore throat or other infection. Written instruction may be useful for some patients.
Requirements for monitoring vary depending on the medication, and can be obtained from sources such as BNF or MIMs.
References:
Andersohn F, Konzen C, Garbe E. Systematic review: Agranulocytois Induced by Nonchemotherapy Drugs. Ann Intern Med 2007;146:657-665.
Andrès E, Zimmer J, Affenberger S, et al. Idiosyncratic drug-induced agranulocytosis: Update of an old disorder. Eur J Intern Med 2006;17(8):529-35.
Comments recieved about this article
22 August 2011 Comment from: KUADZI KINGSLEY
Very impressive, I will be very happy if the MCH,MCHC. will be explained with diagrams.
University of Ghana hospital
hematology laboratory
legon,Ghana
west Africa.
Printer friendly PDF.
Comments recieved about this article
Comment from:
KUADZI KINGSLEY
University of Ghana hospital
hematology laboratory
legon,Ghana
west Africa.