Myelodysplastic Syndromes

Last updated: March 25, 2026

Myelodysplastic syndromes are a group of disorders that are characterised by dysplastic and ineffective haematopoiesis. This leads to abnormal growth of pluripotent stem cells in the bone marrow, causing deficiencies affecting several cell lines.

It is sometimes referred to as a “pre-leukaemic” state since there is a risk of transformation into acute leukaemia. It peaks at 70+ years of age.

Myeloproliferative neoplasms (MPN) vs. myelodysplastic Syndrome (MDS) vs. acute Myelogenous Leukemia (AML)

Features	MPN	MDS	MDS/MPN	AML
Bone Marrow Cellularity	Increased	Usually increased	Usually increased	Usually increased
% Marrow blasts	Normal or <10%	Normal or <20%	Normal or <20%	Minimal
Maturation	Present	Present	Present	Minimal
Morphology	Normal	Abnormal	Abnormal	Dysplasia can be present
Haematopoiesis	Effective	Ineffective	Effective or ineffective	Ineffective
Blood counts	One or more myeloid cells increased	Low, one or more cytopenia	Variable	Variable
Hepatosplenomegaly	Common	Uncommon	Common	Uncommon

WHO Classification of Myelodysplastic Syndromes (MDS)
- MDS with single lineage dysplasia (MDS-SLD)
- MDS with multiple lineage dysplasia (MDS-MLD)
- MDS with ring sideroblasts (MDS-RS)
- MDS with isolated del (5q)
  - Amenable to treatment with lenalidomide
- MDS with excess blasts (MDS-EB)
- MDS unclassifiable (MDS-U)
- Refractory cytopenia of childhood
Risk factors
- Genetic
  - Down Syndrome
  - Trisomy 8
  - Mosaicism
  - Monosomy 5
  - Monosomy 7
  - Del 5q
  - NFT1
  - Germ cell tumours (embryonal dysgenesis),
  - Congenital neutropenia: Kostmann’s or Schwachman-Diamond syndrome
  - DNA repair deficiencies: Fanconi anaemia, Ataxia telangiectasia, Bloom syndrome, Xeroderma pigmentosum
  - Mutagen-detoxification (GSTQ1-null)
- Advanced age
- Cytotoxic therapy
  - Alkylating agents
  - Topoisomerase II inhibitors
  - Beta-emitters such as radioactive p-32
- Hematopoietic cell transplantation
- Environmental and occupational toxins
  - Benzene
  - Tobacco
- Aplastic anemia
- Paroxysmal nocturnal hemoglobinuria (PNH)
- Polycythemia vera
- Obesity
Signs and symptoms
- Symptoms of anaemia
- Severe and frequent infections due to neutropenia
- Easy bruising and bleeding due to thrombocytopenia
Differentials
- Vitamin B12 deficiency
- Folate deficiency
- Aplastic anaemia
- Chronic myelomonocytic leukaemia (CML)
Investigation
- Complete Blood Count
  - Macrocytic or normocytic anaemia
  - Low reticulocyte count
  - Neutropenia
  - Thrombocytopenia (Variable)
  - Pancytopenia (50% of cases at presentation)
- Decreased reticulocyte count
- Peripheral blood film
  - Poikilocytosis
  - Nucleated RBCs
  - Basophilic stippling
  - Howell-Jolly bodies
  - Pseudo Pelger-Huet anomaly
  - Auer rods
  - Hypersegmented neutrophils
  - Giant platelets
  - Hypogranular or agranular platelets
- Bone Marrow Studies
  - Dysplastic changes in erythroid precursors
  - Ringed sideroblast in iron staining
  - Hyperplasia with dysgranulopoiesis
  - Dysmegakaryopoiesis – pawn ball megakaryocytes
  - Abnormal localisation of immature precursors (ALIP)
- Cytochemistry
  - Iron staining (Perls-prussian reaction) to identify ringed sideroblasts
  - PAS staining of erythroblasts to assess dyserythropoiesis
  - Peroxidase or Sudan Black B to detect the myeloid lineage of blasts
  - NSE or CAE to assess myeloid blasts
- Immunocytochemistry and Flow cytometry to exclude lymphoid origin of primitive blasts
- Genetic and Molecular (TR-PCR, FISH, Karyotyping) to detect chromosomal anomalies
Treatment
- Tranfusion
- Iron chelation therapy due to repeated transfusions
- Antibiotics fo rinfectin
- Erythropoietin +/- G-CSF for anaemia
- Bone marrow transplant is curative, but may be inappropriate since most patients are > 70 years old
- Thalidomide analogues (lenalidomide) or hypomethylating agents (azacitidine and decitabine) may improve quality of life
Complications
- Life-threatening haemorrhage
- Neutropenia sepsis
- Progression to AML (30%)
- Complications of chemotherapy
- Complications of bone marrow transplant

Reference Intervals ›

Biochemistry

ACTH	P: <80 ng/L
ALT	P: 5–35 U/L
Albumin	P: 35–50 g/L
Aldosterone	P: 100–500 pmol/L
Alk. phosphatase	P: 30–130 U/L
α-Amylase	P: 0–180 IU/dL
α-Fetoprotein	S: <10 kU/L
Angiotensin II	P: 5–35 pmol/L
ADH	P: 0.9–4.6 pmol/L
AST	P: 5–35 U/L
Bicarbonate	P: 24–30 mmol/L
Bilirubin	P: 3–17 μmol/L
BNP	P: <50 ng/L
CRP	P: <10 mg/L
Calcitonin	P: <0.1 mcg/L
Calcium (ionized)	P: 1.0–1.25 mmol/L
Calcium (total)	P: 2.12–2.60 mmol/L
Chloride	P: 95–105 mmol/L
Cholesterol	P: <5.0 mmol/L
VLDL	P: 0.128–0.645 mmol/L
LDL	P: <2.0 mmol/L
HDL	P: 0.9–1.93 mmol/L
Cortisol AM	P: 450–700 nmol/L
Cortisol Midnight	P: 80–280 nmol/L
CK ♂	P: 25–195 U/L
CK ♀	P: 25–170 U/L
Creatinine	P: 70–100 μmol/L
Ferritin	P: 12–200 mcg/L
Folate	S: 2.1 mcg/L
FSH	P: 2–8 U/L ♂; >25 menopause
GGT ♂	P: 11–51 U/L
GGT ♀	P: 7–33 U/L
Glucose (fasting)	P: 3.5–5.5 mmol/L
Growth hormone	P: <20 mu/L
HbA1C (DCCT)	B: 4–6%
HbA1C (IFCC)	B: 20–42 mmol/mol
Iron ♂	S: 14–31 μmol/L
Iron ♀	S: 11–30 μmol/L
Lactate (venous)	P: 0.6–2.4 mmol/L
Lactate (arterial)	P: 0.6–1.8 mmol/L
LDH	P: 70–250 U/L
LH	P: 3–16 U/L
Magnesium	P: 0.75–1.05 mmol/L
Osmolality	P: 278–305 mosmol/kg
PTH	P: 0.8–8.5 pmol/L
Potassium	P: 3.5–5.3 mmol/L
Prolactin ♂	P: <450 U/L
Prolactin ♀	P: <600 U/L
PSA	P: 0–4 mcg/mL
Protein (total)	P: 60–80 g/L
Red cell folate	B: 0.36–1.44 μmol/L
Renin (erect)	P: 2.8–4.5 pmol/mL/h
Renin (recumbent)	P: 1.1–2.7 pmol/mL/h
Sodium	P: 135–145 mmol/L
TBG	P: 7–17 mg/L
TSH	P: 0.5–4.2 mU/L
T4	P: 70–140 nmol/L
Free T4	P: 9–22 pmol/L
TIBC	S: 54–75 μmol/L
Triglycerides	P: 0.50–2.3 mmol/L
T3	P: 1.2–3.0 nmol/L
Troponin T	P: <0.1 mcg/L
Urate ♂	P: 210–480 μmol/L
Urate ♀	P: 150–390 μmol/L
Urea	P: 2.5–6.7 mmol/L
Vitamin B12	S: 0.13–0.68 nmol/L
Vitamin D	S: 50 nmol/L

Arterial Blood Gases

pH	7.35–7.45
PaCO₂	4.7–6.0 kPa
PaO₂	>10.6 kPa
Base excess	±2 mmol/L

Urine

Cortisol (free)	<280 nmol/24h
Hydroxyindole acetic acid	16–73 μmol/24h
Hydroxymethylmandelic acid	16–48 μmol/24h
Metanephrines	0.03–0.69 μmol/mmol cr.
Osmolality	350–1000 mosmol/kg
17-Oxogenic steroids ♂	28–30 μmol/24h
17-Oxogenic steroids ♀	21–66 μmol/24h
17-Oxosteroids ♂	17–76 μmol/24h
17-Oxosteroids ♀	14–59 μmol/24h
Phosphate (inorganic)	15–50 mmol/24h
Potassium	14–120 mmol/24h
Protein	<150 mg/24h
Protein/creatinine ratio	<3 mg/mmol
Sodium	100–250 mmol/24h

Haematology

WCC	4.0–11.0 ×10⁹/L
RBC ♂	4.5–6.5 ×10¹²/L
RBC ♀	3.9–5.6 ×10¹²/L
Hb ♂	130–180 g/L
Hb ♀	115–160 g/L
PCV ♂	0.4–0.54 L/L
PCV ♀	0.37–0.47 L/L
MCV	76–96 fL
MCH	27–32 pg
MCHC	300–360 g/L
RDW	11.6–14.6%
Neutrophils	2.0–7.5 ×10⁹/L (40–75%)
Lymphocytes	1.0–4.5 ×10⁹/L (20–45%)
Eosinophils	0.04–0.44 ×10⁹/L (1–6%)
Basophils	0–0.10 ×10⁹/L (0–1%)
Monocytes	0.2–0.8 ×10⁹/L (2–10%)
Platelets	150–400 ×10⁹/L
Reticulocytes	0.8–2.0% / 25–100 ×10⁹/L
Prothrombin time	10–14 s
APTT	35–45 s

Paediatric

Pulse Rate (bpm)
Neonate	140–160
Infant <1yr	120–140
1–5 years	110–130
5–12 years	80–120
>12 years	70–100
Respiratory Rate (tachypnoea)
0–2 months	≥60/min
2–12 months	≥50/min
1–5 years	≥40/min
>5 years	≥30/min
Blood Pressure (mmHg)
Term	65/45
1 year	75/50
4 years	85/60
8 years	95/65
10 years	100/70
Weight Formulas
3–12 months	(a + 9)/2 kg
1–6 years	2a + 8 kg
>6 years	(7a − 5)/2 kg
Haemoglobin (g/dL)
Term newborn	13–20
1 month	11–18
2 months	10–15
1–2 years	10–13
>2 years	11–14
MUAC (6 months–5 years)
Obese	>17.5 cm
Normal	13.5–17.4 cm
At risk	12.5–13.4 cm
Moderate malnutrition	11.5–12.4 cm
Severe malnutrition	<11.5 cm
Developmental Milestones
Social smile	1.5 months
Head control	4 months
Sits unsupported	7 months
Crawls	10 months
Stands unsupported	10–12 months
Walks	12–13 months
Talks	18 months
CSF WBC (/mm³)
Term newborn	0–25
>2 weeks	0–5

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