How Can We Help?
Parasitic infections.
Hydatid disease
Hydatid disease of the abdomen and chest still occurs and has fairly characteristic presentations
Chest. The patient usually presents with a history of cough, quite often with mild blood staining of sputum. Very occasionally, there will be a clear history of coughing up ‘grapes’ or ‘meat’ (by which is usually meant something that looks like a membrane).
Examination may reveal a localised area of dullness, or may be normal. CXR shows a large round ball, which if contiguous with the pleura may be mistaken for an odd pleural effusion.
Do not be tempted to aspirate it. If you do, the procedure seems relatively innocuous except for the tachycardia you ought to experience on aspirating what looks like tap water. The problem for the patient is that the associated leak may disseminate the infection. Diagnosis is easily confirmed on ultrasound (a CT is not necessary for this unless the lesion can’t be seen on U/S)
Once recognised, management is primarily surgical unless the patient is a poor operative risk, in which case it is worth giving albendazole 400 mg 12 hourly (15 mg/kg/d) for a month. It is common to give three courses of a month each, with two week gaps between each course. Response (cure or improvement) is expected in only 60-70%.
Abdomen. This usually presents as a mass or an enlarged liver, and the diagnosis is confirmed on ultrasound. Management is again surgical, after an initial course of albendazole as above. Percutaneous aspiration, injection, and re-aspiration (PAIR) is probably a feasible alternative if ultrasound expertise is adequate.
Enteric tapeworm and roundworm infestations.
Patients often volunteer information about these intestinal dwellers, or more alarmingly, bring them along for your edification. They are endemic in poorer communities, and probably often do little harm while in low numbers. Massive infestations are associated with malnutrition and intestinal obstruction, and the eosinophilia they sometimes generate can lead to wheezing and a Loeffler’s like CXR (peripheral fluffy infiltrates). Biliary obstruction is described but is very rare.
Management is with either mebendazole 100 mg 12 hourly for six days, or with albendazole 400 mg stat, or perhaps daily for three days in severe infestations. Some authorities recommend a further dose of albendazole after three weeks.
Malaria
More rapid travel means sick patients can present anywhere. The diagnosis should be considered in any patient presenting with fever, unconsciousness or hypoglycaemia. Even if the patient has none of these, but just feels unwell after travelling recently, consider the disease. Individuals born in malaria areas often consider themselves immune, and thus are surprised when contracting it when returning home after an absence of some years.
Highly suggestive features are fever, vomiting and a soft splenomegaly. A FBC showing thrombocytopenia also has a high positive predictive value. The presence of a leukocytosis in an ill patient with confirmed malaria should raise concerns about intercurrent gram negative sepsis. Wise words from other doctors saying ‘it doesn’t look like malaria’ should usually be ignored, as should an initially negative smear. Do the serology as well, and repeat the smear.
If in doubt about an ill patient, rather treat than watch the patient deteriorate. Admit and observe all patients with suspected malaria, as deterioration at home can be rapid.
Never diagnose influenza in a traveller until you are quite, quite sure that it isn’t malaria.
Treatment
Mild malaria: Relatively well patients with a completely normal sensorium, no vomiting, no jaundice or bleeding, and euglycaemia with normal renal and liver function and a parasite count of less than 5% can be treated with artemether/lumefantrine 20/120mg, 4 tabs 2x/d for three days with milk or fatty food (2nd dose 8 hrs after 1st, then 12 hrly for total 6 doses in 3 days, a total of 24 tablets.) An alternative is oral quinine 600 mg 3x/d (10 mg/kg 3x/d). for 7 days.
Severe malaria: (Not ambulant, or any evidence of organ dysfunction, or parasite count >5%.) Intravenous artesunate is preferable if available:
Artesunate IV, 2.4 mg/kg/ dose. Give first three doses 12 hours apart (i.e. at 0, 12 and 24 hours.) Thereafter the same dose daily until able to tolerate oral artemether/lumefantrine. (For a 70 kg patient, this would thus be 168 mg 12 hourly for three doses, then 168 mg daily.)
If no IV artesunate: give a loading dose of intravenous quinine sulphate 20 mg/kg in 1 litre of 5% dextrose water over four hours (i.e. 4 or 5 amps of 300 mg/ml in a litre). This is followed eight hours later (i.e. four hours after the first infusion over four hours finishes) by a maintenance dose of 10 mg/kg 3x/d – i.e. about 600 mg 8 hourly. Tinnitus and vertigo are almost invariable at these doses, but soldier on and treat symptomatically with metoclopramide. Once the vomiting has settled and the patient is well enough, treatment can be changed to the same dose orally. If IV therapy is needed for >48 hours reduce each dose to 7.5 mg/kg.
Dosing of quinine is ideally on a mg/kg lean body mass basis, with the dose being 10 mg quinine base/kg given 3x/d – i.e. a total dose of 30 mg/kg/day. The loading dose of 20 mg/kg initially should be omitted if the patient has taken any chloroquine, quinine or mefloquine already, and it is unclear if it really achieves much. In patients who are confused and pulling out the drip, the dose can be given intramuscularly – dilute to 10 ml and give half into each lateral thigh. Absorption is not that reliable.
Duration: Change to oral as soon as the patient has improved, and give treatment for a total of 7 days.
Doxycycline 100 mg per day for 7 days is commonly added 2-3 days later for those given quinine (it is not needed if using artemether/lumefantrine) although this combination is less well evaluated than the combination of quinine and tetracycline.1 It is not to aid initial response but to ensure adequate clearing by reducing resistance, so there is no rush to give it early, and if you do so you may confuse the side effects of quinine with those of doxycycline. In pregnancy, clindamycin 600 mg 2x/d for 7 days is an alternative.
Bacteraemia. In very ill patients, associated bacteraemia is well described, and the addition of ceftriaxone 1 g daily IV (after blood culture) is reasonable.
Suspected quinine resistance.
Most patients with malaria start to feel better within 24 – 48 hours of starting treatment, although the fever may take a little longer to settle completely. If not settling clinically or if there isn’t a 75% reduction in parasite count by 48-72 hours, then resistance should be suspected. Ask for help.
Other malaria species (beside falciparum) are treated differently. If the laboratory (or you) is not entirely sure that it is one of these other species, rather treat as if it is falciparum, particularly if the patient is very ill.
P malariae – chloroquine base 600 mg stat, then another 300 mg 8 hours later, then 300 mg on the second day and another 300 mg on the third day.
P ovale – same chloroquine regimen, but will also need to add primaquine, usually at a later stage, to clear the intrahepatic form. The dose is primaquine base 15 mg per day (one tablet) for 14 days. This is unregistered in the country – ask the pharmacy for help in obtaining it from the manufacturer on a named patient basis.
Perspective – artesunate
The use of quinine as primary therapy for severe malaria is long-established, but there are growing concerns about resistance and some reduction in efficacy. An Asian study2 (where quinine resistance is well documented) looked at intravenous artesunate in severe malaria. In this unblinded trial, artesunate was associated with 14.7% mortality compared with 22.4% for quinine (ARR 7.8%, NNT 13, CI 9 to 26 – the abstract reports the relative reduction of 34.7% as the AR.)
Severe malaria was diagnosed as a positive blood film together with one or more of: a. GCS<11; b. shock (low BP and cool peripheries) ; c. Bicarb < 15 mmol/l; d. Urea > 17; e. glucose < 2.2; f. Respiratory rate > 32; g. Parasitaemia > 10%: h. Either jaundice or Hct < 20% with more than 100 000 parasites per microlitre.