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1st August 2023
Other Types of Infections
| Infection | Clinical features | Management |
|---|---|---|
| Pneumocystis jiroveci (fungal) | Most commonly causes pneumonia (PCP), characterised by the gradual onset of exertional shortness of breath, non-productive cough, fever, and malaise.
Patients may have normal oxygen saturations at rest but quickly desaturation on exertion. Chest x-ray shows characteristic bilateral perihilar infiltrates, and high-resolution CT shows ground glass changes. Diagnosis is confirmed through silver staining or bronchoalveolar lavage aspirate or PCR of fungal DNA from a serum sample. |
First line treatment is a 21 day course of intravenous co-trimoxazole, with intravenous pentamidine, dapsone or trimethoprim as alternatives.
Corticosteroids may be given in severe cases, and ventilation may also be required. Prophylaxis with oral co-trimoxazole is commonly given to HIV patients with a CD4 count of less than 200 and to renal transplant patients. |
| Cryptococcus (fungal) | Cryptococcal meningitis is the most common presentation in HIV patients, although it may also cause pneumonia.
Causes a gradual onset illness, beginning with fever, headache and nausea, before progressing to changes in level of consciousness. Seizures, focal neurology, neck stiffness and photophobia are less commonly seen. Indian ink staining of CSF from lumbar puncture visualises organisms and confirms the diagnosis. |
Treatment is with intravenous liposomal amphotericin B. |
| Candida (fungal) | Most commonly due to Candida albicans yeast. Oral candidiasis is very common in HIV patients – characteristic creamy-white plaques on the tongue and oral mucosa.
Oesophageal candidiasis presents with painful swallowing and reduced oral intake, and may be able to visualise plaques at the back of the throat (though endoscopy may be required). Concurrent oral thrush often occurs. Diagnosis is generally clinical, although swabs can be taken. |
Oral candidiasis is treated with oral nystatin as the first line, followed by oral fluconazole for severe cases.
Oesophageal candidiasis is treated with oral fluconazole. |
| Aspergillus (fungal) | Aspergillus spores are air-borne and hence spread through inhalation. Rare even in HIV patients unless they have comorbid respiratory illness or additional immunosuppression with medications.
Causes both pneumonia and upper respiratory tract infection – commonly sinusitis. |
Antifungal agent voriconazole is the first line treatment, with liposomal amphotericin B or caspofungin as alternatives. |
| Histoplasmosis (fungal) | Rare in the UK, it is most prevalent in the Americas – especially the Ohio and Mississippi river valleys.
Often indolent in healthy individuals, but in those who are immunocompromised causes a pneumonia-type illness. |
First line treatment is with liposomal amphotericin B. |
| Toxoplasmosis (protozoa) | Many people are infected with Toxoplasma gondii – found in undercooked meat, cat faeces and may be transmitted vertically. However, it only manifests disease in immunocompromised individuals and is associated with HIV.
Encephalitis and cerebral abscesses are the most common form (cerebral toxoplasmosis). Presents with fever, headache, confusion and seizures and may be associated with focal neurological deficits. Characteristic multiple ring-enhancing lesions on contrast CT head scans, which can be confirmed through MRI. |
Minimum six week course of pyrimethamine intravenously, combined with sulfadiazine and folinic acid. |
| Cryptosporidiosis (protozoa) | The infection leads to a self-limiting diarrhoeal illness in people with a healthy immune system, but in immunocompromised individuals can cause a severe watery diarrhoea associated with acute abdominal pain, vomiting, and weight loss.
Cysts are formed, which attach themselves to the wall of the small bowel and can be seen with Kinyoun acid-fast stain to confirm the diagnosis. |
Supportive treatment. |
| Leishmaniasis (protozoa) | Endemic in South America, tropical regions of Africa, and the Mediterranean – so should be considered in immunocompromised individuals who have travelled to these areas.
Causes non-specific illness with fever, malaise, diarrhoea and weight loss. Severe illness can lead to splenomegaly, anaemia and thrombocytopenia. No reliable diagnostic test. |
First line treatment is with liposomal amphotericin B. |
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