A problem that occurs during or after a trip does not necessarily need to have a causal connection with that trip. he questions that need to be asked on finding an enlarged spleen are:

• What is the degree of splenomegaly?
• Is it only the spleen or is the liver involved as well?
• Is there fever?
• Is it an acute or a chronic problem?

Greatly enlarged means more than 10 cm below costal margin.

Consider :

• Hyperreactive malaria splenomegaly. Fever. Plasmodium trophozoites should be looked for, though these will usually be present only in very low numbers. Malaria serology will be strongly positive and the IgM content of the blood greatly increased.
• Visceral leishmaniasis (kala azar). Fever. It is essential that amastigotes are detected. Serology can be suggestive.
• Portal hypertension associated with liver cirrhosis or fibrosis, e.g. due to bilharziosis (Schistosoma mansoni). There may be haematemesis in the history (oesophageal varices).
• Splenic cyst. This occasionally concerns an Echinococcus cyst. Ultrasound and serology will give a first indication here. Dermoid cysts, old haematomas and mesenchymal inclusion cysts should be included in the differential diagnosis.
• Beta-thalassaemia (children with Cooley's anaemia). This is a haemolytic condition with pronounced microcytosis.
• Child with sickle cell anaemia and a splenic-sequestration crisis. This is a medical emergency which tends to occur in young children.
• Chronic myelocytic leukaemia, as well as chronic lymphocytic leukaemia (CLL). The peripheral blood suggests the diagnosis. Bone marrow analysis should be carried out.
• Myelofibrosis. Myeloid metaplasia in the liver and the spleen is secondary to sclerosis of the bone marrow. The spleen can be massively enlarged in these cases. A bone marrow biopsy is essential, though aspiration is usually not possible ("dry tap"). There is often a laboratory result indicating leukoerythroblastic blood. Thrombocytosis is likewise frequent.
• Gaucher's disease. This metabolic disease has several variants, one of which occurs in adults. Hepatomegaly and bone lesions are frequently associated with this disease. This is an inherited enzyme deficiency disorder. It is the most common lipid-storage disorder accumulation of glucocerebroside affecting Jewish people from East European ancestry.

Moderately enlarged means 5-10 cm below costal margin.

Consider the above-mentioned points together with

• Recurrent malaria infections
• Trypanosomiasis, both the African forms and the Latin American form, Chagas’ disease
• Syphilis, including congenital lues
• Vaquez's disease (polycythaemia vera). Increased haematocrit, leukocytosis, thrombocytosis, pruritus and signs of hyperviscosity orientate the diagnosis. The difference with polycytemia secondary to hypoxia (chronic lung disease, high altitude) is usually obvious. Polycythaemia occurs in rare cases with certain tumours. Relative polycythaemia associated with dehydration and haemorrhagic dengue poses no diagnostic problem in practice.
• Congenital spherocytosis
• Various myelodysplasias and leukaemias may be accompanied by splenomegaly. Examination of a blood smear and bone marrow suggests the diagnosis. Lymphomas can likewise cause enlargement of the spleen.

Slightly enlarged means less than 5 cm below costal margin.

Consider the above-mentioned points together with

• Acute infections: malaria, typhoid fever, rickettsioses and Q-fever, mononucleosis, melioidosis, bartonellosis, babesiosis. A clinical condition of atypical pneumonia with enlargement of the spleen must lead to suspicion of, among other things, psittacosis.
• Subacute infections, such as brucellosis, secondary syphilis, trichinosis, Katayama fever (acute early schistosomiasis) and subacute bacterial endocarditis.
• Chronic infections, such as leprosy, histoplasmosis and lymphatic filariosis (W. bancrofti). Amyloidosis secondary to chronic infection must be borne in mind.
• Various:
• Sickle cell anaemia can cause enlargement of the spleen in very young children (even without a sequestration crisis). Atrophy of the spleen occurs later (in general after about the age of 5).
• Sarcoidosis
• G6PD-deficiency, with acute haemolytic episode triggered by infection, food (favism) or medication.
• Amyloidosis, primary or secondary.
• Felty's syndrome (complication of rheumatoid arthritis°. Neutropenia is typical.
• Still’s disease (juvenile rheumatoid arthritis) is characterised by fever, rash, iritis, leukocytosis, splenomegaly and generalised lymphadenopathy. Arthralgia and arthritis especially affect the larger joints. Pleurisy and pericarditis can occur.