Respiratory tract viruses

Viral respiratory infections, including coronavirus, rhinovirus, adenovirus, respiratory syncytial virus, human metapneumovirus, parainfluenza viruses, and influenza viruses, are a substantial cause of morbidity and mortality worldwide, most notably the COVID-19 pandemic. Transmission occurs through direct contact, contaminated fomites, and large airborne droplets, with long-range transmission by small particle aerosols reported in at least some instances of influenza and severe acute respiratory syndrome. Clinical syndromes affect the upper and/or lower respiratory tract, including coryza, pharyngitis, croup, bronchiolitis, and pneumonia. Each syndrome can potentially be caused by several viruses, and each respiratory virus can be associated with different clinical syndromes. Measles is a major cause of lower respiratory tract infections and fatality in tropical countries.

Newly discovered viruses

Although humans are affected by an enormous range of microorganisms, almost all newly discovered emerging pathogens are viruses that are often zoonotic or vector-borne. These emerging viruses often have high baseline mutation rates, allowing them to adapt relatively easily to new hosts and enabling them to take advantage of new epidemiological opportunities provided by the changing environment. A range of apparently new human viral pathogens has been reported increasingly in international outbreak information over the last few years, most recently SARS-CoV-2 as the cause of the COVID-19 pandemic that started in Wuhan (China) in December 2019 and has now spread worldwide with devastating consequences. In addition to respiratory coronaviruses, emerging viruses that might be of particular global public health importance includeZika virus and severe fever and thrombocytopenia syndrome virus. Other emerging viruses of importance include bocavirus, Bufavirus, PARV4, human parechovirus, Itaya, Heartland, and Bourbon virus. The human pathogenicity of other emerging viruses is less certain.

Smoking cessation

Smoking is harmful to health. The main harms are cardiovascular disease, lung cancer, and chronic obstructive pulmonary disease. Most people who smoke start in their teens, and some become addicted. Stopping smoking may be prompted by public policy or price rises, and while physicians have a role in lobbying for these, the main opportunity a physician has to help their patients stop smoking is during the medical consultation. Advising the patient to stop has some effect, but is more likely to be effective when combined with practical help, the best form of which is regular face-to-face meetings to support the patient combined with drugs that reduce craving. Helping a patient to stop smoking greatly reduces their risk of illness and early death.

Personality disorders

People have characteristic ways of perceiving, thinking about, and responding to the world around them that are relatively stable over time and across situations; this is referred to as their personality. A diagnosis of personality disorder is made when the personality is extreme and maladaptive and causes difficulty or distress to the person themselves or to others. People with personality disorders are often encountered in medical settings, which may be because they have self-harmed, suffered problems from drug or alcohol use, or been injured because of unwise behaviour. Personality disorders also complicate the medical management of medical conditions, for example, by non-adherence to recommended treatment. The effective short-term management of personality disorders in medical settings requires: (a) recognition of the diagnosis; (b) creation of a management plan; and (c) consistent response to the problematic behaviours adhered to by all relevant staff.

The psychiatric assessment of the medical patient

Medically ill patients often have psychiatric illness. Physicians can and should detect and diagnose these illnesses during their standard medical assessment. All that is required is knowledge of key questions to ask patients, awareness of the clinical signs that may be observed, and an appreciation of the value of additional information from relatives, other clinicians, and the medical record. The aims are to detect and diagnose psychiatric disorders; assess the risk of self-harm or harm to others; establish the need for treatment or referral for a psychiatric opinion; provide the basis for clear and effective communication with a psychiatrist; and to communicate to the patient that you are interested in all aspects of their suffering and thereby establish a clinically effective relationship with them.

General introduction

All physicians experience situations in which they need the knowledge, skills, and attitudes commonly thought of as belonging to psychiatry. This section of the book aims to help physicians to acquire these. It includes: (1) guidance on how to assess medical patients for psychiatric illness; (2) information about psychiatric presentations and the differential diagnoses most relevant to general medical practice; (3) brief reviews of the psychiatric disorders most commonly seen in general medical practice and the practical management of these; (4) guidance on the use of psychotropic drugs and psychological treatments when given as part of general medical care; (5) evidence-based strategies for helping patients who are smoking, using alcohol excessively, or who are overweight.

Idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) (also called pseudotumour cerebri and, previously, benign intracranial hypertension) is a syndrome of raised intracranial pressure in the absence of an intracranial mass lesion, enlargement of the cerebral ventricles, or venous sinus thrombosis. IIH affects predominantly obese women of childbearing age (>90%). The condition has considerable morbidity from permanent visual loss (up to 25% of cases) and chronic disabling headaches, which result in poor quality of life. Patients presenting acutely with papilloedema must be evaluated urgently for secondary causes of raised intracranial pressure (e.g. space occupying lesion and venous thrombosis). After this, the priority is to assess accurately the threat to vision. In most patients, the condition becomes chronic and the disease burden is mostly from chronic headaches, which need active management, alongside visual monitoring. This chapter does not cover paediatric IIH.

Narcolepsy

Narcolepsy with cataplexy is a specific syndrome of daytime sleepiness, disrupted nocturnal sleep, and episodes of sudden loss of muscle tone—provoked by the anticipation of emotions (in particular laughter)—leading to a tendency to fall, mouth opening, dysarthria or mutism, and facial muscle jerking. It is associated with loss of hypocretin (orexin) neurons in the hypothalamus, hypocretin concentrations in the cerebrospinal fluid below 110 pg/ml, and the HLA genotype DQ B1*0602. A less common form of narcolepsy without cataplexy probably has a different, as yet unknown, pathogenesis. Once established, narcolepsy is lifelong; spontaneous recovery does not occur. Symptomatic treatment—which is essential for school performance, work, driving ability, and quality of life—is with stimulant (e.g. amphetamine) and anticataplectic (e.g. clomipramine) drugs. More recently, sodium oxybate, an anaesthetic, has been used to induce deep sleep overnight, resulting in improvements in all symptoms.

Investigation of central motor pathways: Magnetic brain stimulation

The ability to stimulate percutaneously the central nervous system of conscious humans without causing pain has opened up new areas for neurophysiological investigation in the early diagnosis of neurological disease, and has furthered the understanding of normal and abnormal motor control. Magnetic stimulators are now available that can excite both upper and lower limb areas of the motor cortex, as well as cranial nerves, motor roots, and deeply sited peripheral nerves. This chapter looks at their application in a clinical scenario, which include: measurement of central motor conduction time; assessment of completeness of spinal cord injury; and possibly evaluation of neurodevelopmental delay in children with neurodegenerative and other related diseases. The technique can be used serially to monitor progress of disease or after neurological injury or to examine the effects of drugs, and it can be used safely in neonates and children.

Cutaneous reactions to drugs

Adverse reactions to medications are common and important cause of iatrogenic illness. Severe cutaneous adverse drug reactions include toxic epidermal necrolysis, Stevens–Johnson syndrome, drug reaction with eosinophilia and systemic symptoms, and acute generalized exanthematous pustulosis, which together constitute 2% of all adverse drug reactions and may be life-threatening. Less severe drug-induced skin reactions such as exanthems, urticaria, lichenoid drug rashes, and fixed drug eruptions are more common, sometimes termed benign cutaneous adverse reactions, and generally resolve without sequelae. Drugs may also cause adverse events due to alteration of the normal function of the skin or its appendages. This may take the form of photosensitivity, abnormal pigmentation, or disrupted growth of hair or nails.