Sexually Transmitted Infections

2 Sexually Transmitted Infections



HIV/AIDS




Case history


A 35-year-old European man is newly diagnosed HIV positive. He was tested because he had been feeling generally unwell over a 6-month period and had lost weight. He presents with a persistent cough, which has developed and worsened over the preceding 2 weeks.


On examination he has a temperature of 39°C, his pulse is 100/min and he has a respiratory rate of 20/minute.


There are signs of oral candidiasis. He is on no regular medication. You are the medical SHO on acute take.



What are the likely diagnoses and the immediate management?


Pneumocystis jiroveci pneumonia commonly has an insidious onset, often with worsening shortness of breath and deteriorating exercise tolerance; the cough is usually non-productive.



• Examination of the chest can yield few signs other than tachypnoea and tachycardia. Fine inspiratory crackles might be heard.


• The CXR is often normal or shows little, although bilateral perihilar interstitial shadowing with a bat-wing appearance is the characteristic abnormality.


• High-resolution CT of the lungs shows a characteristic ground glass appearance even when there is little to see on the plain CXR.


• Oxygen saturation characteristically falls on exercise. Arterial blood gas analysis might show hypoxia with a normal carbon dioxide and pH.


• The diagnosis is made on broncho-alveolar lavage.


The introduction of highly active anti-retroviral therapy (HAART) in HIV-infected people has led to a significant decline in pneumocystis and the infection is now most commonly seen in those not previously recognised as HIV infected. Pneumocystis infection occurs most frequently in the context of significant immunosuppression, when the CD4 count is < 200 cells/mm3. There may be clinical markers of poor immune function, such as candidiasis, as in this patient.


Primary prophylaxis (cotrimoxazole is first line) is recommended in those who are aware of their HIV status if their CD4 count falls into this range. This intervention alone has reduced the incidence of pneumocystis infection in HIV-infected populations. Pneumocystis pneumonia is an AIDS-defining diagnosis.



How would you treat this patient?


IV cotrimoxazole (trimethoprim 15 mg/kg/day + sulfamethoxazole 75 mg/kg/day) is the preferred first-line treatment, although a significant proportion of patients will develop allergy. IV pentamidine or dapsone plus pyramethamine are also used.


Treatment is given for 3 weeks. Systemic corticosteroids (IV methylprednisolone 40 mg × 4 daily for 5 days) are added in severe cases (PO2 less than 8 kPa). Patients with pneumocystis infection can develop respiratory failure and require ventilatory support. Pneumothorax is a further complication of pneumocystis.


The organism is not cleared by treatment and secondary prophylaxis (usually cotrimoxazole) is recommended. This can be withdrawn later if the patient starts HAART and the CD4 count remains consistently > 200 cells/mm3.


In a patient not already on HAART, initiation of therapy should be discussed with a specialist physician.



What other chest conditions are associated with HIV?



Mycobacteria tuberculosis (MTB)


An organism of high pathogenicity, MTB can develop relatively early in the course of HIV infection. It is particularly common in those who have lived in areas of the world with a high incidence of MTB, e.g. sub-Saharan Africa. Pulmonary infection presents with a cough (usually productive) and chest pain but, in the context of HIV infection, presentation is often insidious and non-specific, with fever, sweats, malaise and weight loss. History of contact with MTB should always be sought, along with details of any previous anti-tuberculous therapy, because in such patients there is a risk of multidrug-resistant tuberculosis (MDRTB). There might be generalised lymph node enlargement or hepatomegaly in addition to signs in the chest. In some cases pulmonary infection is coupled with CNS involvement – either TB meningitis or tuberculoma. The chest radiological changes are few and are frequently atypical, with lower zone changes without cavitation. Other radiological findings include hilar lymphadenopathy, pleural effusion or lobar consolidation.


In patients with HIV, the usual immunological reactions to MTB might be blunted or absent, making diagnosis more difficult. Mantoux tests are rarely helpful because immunosuppressed patients do not produce a normal delayed hypersensitivity reaction. Granuloma formation can be compromised, leading to atypical histological changes. Sputum smears may be negative in up to 50% of those with culture-proven TB. Diagnosis relies heavily on clinical suspicion backed by positive cultures from, e.g. sputum, broncho-alveolar lavage, blood, bone marrow, lymph nodes, as appropriate.


Treatment of TB in HIV co-infected patients presents specific challenges and requires input from a specialist physician. Treatment is similar to that for HIV-negative patients, although intermittent and short-course regimens are not advised.


Therapy should be initiated with four drugs – isoniazid, rifampicin, pyrazinamide and ethambutol – for 2 months. Once sensitivities are confirmed, pyrazinamide and ethambutol can be withdrawn and the other two drugs continued for 4 months, although this might be extended in some circumstances. The drug–drug interactions between anti-retroviral and anti-tuberculous medications are complex and are a consequence of enzyme induction or inhibition. There are interactions between rifampicin derivatives and the protease inhibitor class of anti-retroviral agents, leading to an increase in rifampicin toxicity and reduced protease efficacy. The non-nucleoside reverse transcriptase class also interacts variably with rifampicin, requiring dose alterations. Additionally, there are overlapping toxicities between HAART regimens and anti-tuberculous drugs, in particular hepatotoxicity, peripheral neuropathy and gastrointestinal side effects.



Remember


Any patient in whom the suspicion of TB is great enough to start anti-tuberculous therapy MUST be notified to the local consultant in communicable disease control (CCDC).

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Apr 3, 2017 | Posted by in GENERAL & FAMILY MEDICINE | Comments Off on Sexually Transmitted Infections

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