Anaemia is a frequent occurrence in children who come for adoption, in individuals who have travelled extensively in the tropics and in people from third-world countries. A problem that occurs during or after a trip does not necessarily need to have a causal connection with that trip.

The symptoms are often vague and non-specific: fatigue, dyspnoea, palpitations, tachycardia. Pale mucosae will be encountered in severe anaemia. The nailbed will be pale and with prolonged iron deficiency the nails can become brittle and flat or even hollow (koilonychia). A haematocrit and haemoglobin determination is more reliable than physical examination. It should always be determined whether a microcytic, normocytic or a macrocytic anaemia is involved. Equally it is essential to know reticulocyte numbers to distinguish between anaemias due to excessive blood loss/haemolysis and those due to reduced production. Analysis of the blood shows whether an isolated anaemia is involved, or whether it is part of for example a pancytopenia (e.g. in hypersplenism, in bone marrow infiltration or bone marrow aplasia).

Acute or chronic? Acute severe haemolysis e.g. due to bartonellosis, haemolytic-uraemic syndrome, sickle cell crisis, G6PD-deficiency with a triggering factor or blackwater fever (hyperhaemolysis as a complication with Plasmodium falciparum). Acute internal blood loss is sometimes not immediately obvious (e.g. rupture of the spleen, ruptured ectopic pregnancy, pelvic fracture). If there has not been sufficient time for fluid redistribution, the extent of blood loss can easily be underestimated.

Transfusion necessary or not? Blood should be regarded as a potentially dangerous medicament. It is important to be aware of the (non) safety of a blood transfusion (hepatitis B, C, D, malaria, treponematosis, HIV, Chagas’ disease).

The physical examination should also pay attention to the following points:

• Fever or afebrile?
• Koilonychia, icterus (jaundice), rhagades, glossitis, dysphagia (e.g. due to a Plummer-Vinson oesophageal web. This is however rare).
• Splenomegaly? Hypersplenism in kala azar, portal hypertension or tropical splenomegaly syndrome can cause anaemia or pancytopenia.

In cases of haemolytic anaemia one should suspect , among other things:

• malaria (frequent)
• mononucleosis can be accompanied by acute haemolysis, usually limited in severity.
• Genetically determined haemolytic diseases. G6PD deficiency can induce severe haemolysis when a predisposing factor is present. This situation is frequent in individuals originating from the Mediterranean. Children with beta-thalassaemia major have a very pronounced anaemia with gross splenomegaly. Diagnosis of sickle cell anaemia will usually present no problems. Hereditary spherocytosis can cause enlargement of the spleen, gallstones and chronic haemolysis .
• Autoimmune haemolytic anaemia. This can be due to certain medications (e.g. quinine, alpha-methyldopa).
• Paroxysmal cold haemoglobinuria is a very rare disease described as complication of tertiary syphilis.
• Bartonellosis (rare)
• Babesiosis (rare)
• Certain types of snake venom
• Rarely due to spider bites such as Loxosceles sp, brown recluse spider. Nausea, vomiting, fever, general malaise, local irritation or cutaneous necrosis and haemolytic anaemia can occur. There can be severe consequences in children.
• Hypersplenism
• Haemophagocytosis

Principal causes of microcytic anaemia are:

• occult gastrointestinal blood loss (ancylostomiasis, gastritis, peptic ulcer, stomach or colon carcinoma, severe schistosomiasis)
• gynaecological abnormalities (menorrhagia, metrorhagia, post-partum blood loss). Heavy menstrual blood loss in the absence of gynaecological abnormalities is often caused by von Willebrand disease.
• nutritional deficiency
• gluten enteropathy can result in mixed deficiencies

• thalassaemia major and intermedia
• sickle cell anaemia can be microcytic or normocytic

• Microcytic anaemia can occur with vitamin C deficiency (scurvy). Spontaneous bleeding (e.g. of the gums) and perifollicular petechiae will suggest the diagnosis in these cases.

Principal causes of macrocytic anaemia are:

• Pernicious anaemia. Check for atrophic gastritis, resulting in a lack of intrinsic factor due to anti-parietal cell antibodies.
• Stomach surgery in the medical history (deficiency of intrinsic factor)
• Secondarily to poor nutrition (for example in veganism)
• Diphyllobothrium latum tapeworm (rare)
• Chronic ileitis (Crohn, tuberculosis) / ileal resection (disturbed vitamin B12 absorption)
• Bacterial overgrowth in the small intestine such as in blind loop syndrome, multiple small intestine diverticulae and sclerodermia.
• There are rare genetic abnormalities, such as transcobalamine deficiency, which can result in macrocytic / megaloblastic anemia.

• Deficient nutrition
• Increased requirements: pregnancy, chronic haemolysis.
• Seldom due to medication, e.g. folic acid antagonists (pyrimethamine, trimethoprim), sulphasalazine, phenytoin (diphenylhydantoin)
• Malabsorption : gluten enteropathy, tropical sprue