Chapter 42 The immunosuppressed patient
Patients with immunosuppression present with emergencies related to their increased susceptibility to infection and to their underlying condition.
Failure of a component of the immune system leads to vulnerability to different infective agents.
B cell defects occur in haematological malignancies, myeloma, AIDS and congenital disorders such as common variable immune deficiency. Patients are predisposed to infection by encapsulated bacteria (Streptococcus pneumoniae, Haemophilus influenzae, Neisseria), staphylococci, giardia and enterovirus.
CANCER PATIENTS
Febrile neutropenia
Associated signs of infection may be present such as tachypnoea, tachycardia, altered mental state, dehydration and acidosis. Localising signs may be absent; however, a thorough examination of the lungs, oropharynx, skin, catheters, perineum and perianal area, sinuses and urinary tract is essential and may reveal the site of infection. Non-specific symptoms in the absence of fever may still indicate infection, especially if the patient is on high-dose corticosteroids.
Management
Antifungals
Antifungals are not routinely used in the initial treatment of febrile neutropenia, unless there is evidence of fungal infection such as sinusitis. They may be introduced when fever persists beyond 96 hours, especially in patients with pulmonary infiltrates.
NONINFECTIOUS COMPLICATIONS OF CANCER AND ITS TREATMENT
Spinal cord compression
Hypercalcaemia
Increased osteolysis releases calcium and phosphate into the circulation. This can be caused by primary (myeloma or leukaemia) or metastatic bone lesions (commonly breast or lung) or by the action of paraneoplastic hormone-like substances.
Hypokalaemia is common. The patient may be significantly dehydrated and have renal impairment.
Tumour lysis syndrome
Management
HIV INFECTION
Patients with HIV infection most commonly present with complications of immunosuppression and its treatment. With the improved prognosis of HIV in the era of highly active antiretroviral treatment (HAART), patients increasingly present with medical or surgical conditions unrelated to HIV and, while their treatment may be complicated by their HIV, their outcome and survival may be excellent.